Endocrine function in human obesity

Regulation of GH and GH Signaling by Nutrients

Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.

The effects of obesity on the human body part III: Cardiovascular, digestive, excretory, endocrine, and reproductive

This third installment of The Effects of Obesity on the Human Body discusses the endocrine, digestive, reproductive, cardiovascular, and excretory systems. Obesity is known to upset hormonal balance, leading to widespread metabolic disorders involving organs such as the liver and pancreas. Furthermore, the hypersecretion of leptin from adipose tissue triggers various responses from the cardiovascular and gastrointestinal systems, with implications for energy and nutrient balance and uptake.

Comparing the Effects of Combined Oral Contraceptives Containing Progestins With Low Androgenic and Antiandrogenic Activities on the Hypothalamic-Pituitary-Gonadal Axis in Patients With Polycystic Ovary Syndrome: Systematic Review and Meta-Analysis

Background

Different products of combined oral contraceptives (COCs) can improve clinical and biochemical findings in patients with polycystic ovary syndrome (PCOS) through suppression of the hypothalamic-pituitary-gonadal (HPG) axis.

Objective

This systematic review and meta-analysis aimed to compare the effects of COCs containing progestins with low androgenic and antiandrogenic activities on the HPG axis in patients with PCOS.

Methods

We searched PubMed, Scopus, Google Scholar, ScienceDirect, and Web of Science databases (1980-2017) to identify randomized controlled trials or nonrandomized studies investigating the effect of COCs containing progestins with low androgenic and antiandrogenic activities, including the products containing desogestrel, cyproterone acetate, and drospirenone, on the HPG axis in patients with PCOS. In this meta-analysis, fixed and random effect models were used. Outcomes of interest were weighted mean differences (WMD) of hormonal parameters, including the follicle-stimulating hormone (FSH), luteinizing hormone (LH), LH-to-FSH ratio, estradiol, total testosterone, and sex hormone–binding globulin. Potential sources of heterogeneity were investigated using meta-regression and subgroup analyses. Subgroup analyses were performed based on the used progestin compound and treatment duration. We assessed quality of included studies and their risk of bias using Cochrane guidelines. Publication bias was assessed using Egger test and funnel plot.

Results

COC use was significantly associated with a decrease in gonadotropin levels, including FSH and LH. Use of products containing cyproterone acetate was associated with a decrease in FSH levels after 3 months (WMD=−0.48; 95% CI −0.81 to −0.15), 6 months (WMD=−2.33; 95% CI −3.48 to −1.18), and 12 months (WMD=−4.70; 95% CI −4.98 to −4.42) and a decrease in LH levels after 3 months (WMD=−3.57; 95% CI −5.14 to −1.99), 6 months (WMD=−5.68; 95% CI −9.57 to −1.80), and 12 months (WMD=−11.60; 95% CI −17.60 to −5.60). Use of COCs containing drospirenone for 6 months decreased FSH (WMD=−0.93; 95% CI −1.79 to −0.08) and LH (WMD=−4.59; 95% CI −7.53 to −1.66) levels. Data for products containing desogestrel were few, but this compound generally had no statistically significant influence on gonadotropin levels similar to that observed with COCs containing cyproterone acetate and drospirenone. Use of COCs was not associated with any significant change in LH-to-FSH ratio. COCs containing cyproterone acetate showed maximum effect on gonadotropin suppression. COCs containing cyproterone acetate significantly decreased estradiol concentrations, whereas those containing drospirenone exhibited no such effect. All COCs demonstrated improvement in androgenic profile and had the same effects on total testosterone and sex hormone–binding globulin concentrations. Progestin compound and treatment duration had no statistically significant effects on changing total testosterone and sex hormone–binding globulin levels.

Conclusions

COCs containing cyproterone acetate can effectively suppress gonadotropins, leading to a decrease in androgenic parameters. Although different products of COCs could significantly suppress the androgenic profile, it seems that products containing cyproterone acetate are more effective in suppressing gonadotropin and estradiol levels in patients with PCOS.

Dominance of the hypothalamus-pituitary-adrenal axis over the renin-angiotensin-aldosterone system is a risk factor for decreased insulin secretion

How the association between the hypothalamus-pituitary-adrenal (HPA) axis and the renin-angiotensin-aldosterone system (RAAS) affects glucose metabolism were not well examined in a general population. Participants of the population-based 2015 Iwaki study were enrolled (n: 1,016; age: 54.4 ± 15.1 years). Principal component (PC) analysis identified two PCs: PC1 represented levels of the HPA axis (serum cortisol) and the RAAS (plasma aldosterone) as a whole, and PC2 represented the HPA axis relative to the RAAS (HPA axis dominance). We examined the association between these PCs and glucose metabolism using homeostasis model assessment indices of reduced insulin sensitivity (HOMA-R) and secretion (HOMA-β). Univariate linear regression analyses showed a correlation between PC2 and HOMA-β (β = −0.248, p < 0.0001), but not between PC1 and HOMA-β (β = −0.004, p = 0.9048). The correration between PC2 and HOMA-β persisted after adjustment for multiple factors (β = −0.101, p = 0.0003). No correlations were found between the PCs and HOMA-R. When subjects were tertiled based on PC2, the highest tertile was at greater risk of decreased insulin secretion (defined as the lower one third of HOMA-β (≤68.9)) than the lowest tertile after adjustment for multiple factors (odds ratio, 2.00; 95% confidence interval, 1.35–2.97). The HPA axis dominance is associated with decreased insulin secretion in a Japanese population.

Safety, efficacy and weight effect of two 11β-HSD1 inhibitors in metformin-treated patients with type 2 diabetes

AIMS

We assessed safety and efficacy of two selective 11β-HSD1 inhibitors (RO5093151/RO-151 and RO5027383/RO-838) in this randomized, controlled study in metformin-treated patients with type 2 diabetes.

METHODS

Patients either received placebo (N = 21), RO-151 BID 5 mg (N = 24) or 200 mg (N = 20) or RO-838 QD 50 mg (N = 21) or 200 mg (N = 24) for 28 days. Metabolic assessments comprising of nine-point plasma glucose profiles, oral glucose tolerance tests and determination of metabolic biomarkers including insulin, C-peptide, glucagon, HbA1c and lipids were done at baseline and end of treatment.

RESULTS

Despite the short treatment duration, both RO-151 and RO-838 showed trends for improved HbA1c and consistent reductions in body weight (-0.86 to -1.67 kg) exceeding those observed with placebo (-0.28 kg, p = 0.019 for 200 mg RO-151 vs. placebo). Insulin sensitivity parameters (e.g. HOMA-IR and Matsuda-Index) improved non-significantly with 200 mg RO-151. Lipid parameters did not consistently improve with either compound, but RO-838 led to non-significant increases in triglycerides and VLDL-cholesterol versus placebo. Both compounds were well tolerated and showed inhibitory effects on 11β-HSD1 activity based on urinary corticosteroid excretion. As reported for other 11β-HSD1-inhibitors increased concentrations of ACTH and adrenal androgen precursors were found with RO-151, but not with RO-838.

CONCLUSIONS

Slight metabolic improvements were seen, in particular with RO-151 high dose, however, the observed changes often did not reach statistical significance and were not clearly dose dependent. Studies of longer duration are needed to further investigate potential benefits and risks of these compounds.

Changes in morphology and function of adrenal cortex in mice fed a high-fat diet

BACKGROUND/OBJECTIVES

Obesity is a major risk factor for the development of type 2 diabetes and other debilitating diseases. Obesity and diabetes are intimately linked with altered levels of adrenal steroids. Elevated levels of these hormones induce insulin resistance and cause cardiovascular diseases. The mechanisms underlying obesity-related alterations in adrenal steroids are still not well understood. Here, we investigated how diet-induced obesity affects the morphology and function of the mouse adrenal cortex.

METHODS

We fed animals either a high-fat diet (HFD) or a normal diet (60% kcal from fat or 10% kcal from fat, respectively) for 18 weeks. We then assessed various aspects of adrenal gland morphology and function, as well as basal plasma concentrations of steroid hormones and ACTH.

RESULTS

We show that adrenal glands of mice fed a HFD release more corticosterone and aldosterone, resulting in higher plasma levels. This increase is driven by adrenal cortical hyperplasia, and by increased expression of multiple genes involved in steroidogenesis. We demonstrate that diet-induced obesity elevates Sonic hedgehog signaling in Gli1-positive progenitors, which populate the adrenal capsule and give rise to the steroidogenic cells of the adrenal cortex. Feeding animals with a HFD depletes Gli1-positive progenitors, as the adrenal cortex expands.

CONCLUSIONS

This work provides insight into how diet-induced obesity changes the biology of the adrenal gland. The association of these changes with increased Shh signaling suggests possible therapeutic strategies for obesity-related steroid hormone dysfunction.

Tissue-specific dysregulation of cortisol regeneration by 11βHSD1 in obesity: has it promised too much?

Cushing's syndrome, caused by increased production of cortisol, leads to metabolic dysfunction including visceral adiposity, hypertension, hyperlipidaemia and type 2 diabetes. The similarities with the metabolic syndrome are striking and major efforts have been made to find obesity-associated changes in the regulation of glucocorticoid action and synthesis, both at a systemic level and tissue level. Obesity is associated with tissue-specific alterations in glucocorticoid metabolism, with increased activity of the glucocorticoid-regenerating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) in subcutaneous adipose tissue and decreased conversion of cortisone to cortisol, interpreted as decreased 11βHSD1 activity, in the liver. In addition, genetic manipulation of 11βHSD1 activity in rodents can either induce (by overexpression of Hsd11b1, the gene encoding 11βHSD1) or prevent (by knocking out Hsd11b1) obesity and metabolic dysfunction. Taken together with earlier evidence that non-selective inhibitors of 11βHSD1 enhance insulin sensitivity, these results led to the hypothesis that inhibition of 11βHSD1 might be a promising target for treatment of the metabolic syndrome. Several selective 11βHSD1 inhibitors have now been developed and shown to improve metabolic dysfunction in patients with type 2 diabetes, but the small magnitude of the glucose-lowering effect has precluded their further commercial development.This review focuses on the role of 11βHSD1 as a tissue-specific regulator of cortisol exposure in obesity and type 2 diabetes in humans. We consider the potential of inhibition of 11βHSD1 as a therapeutic strategy that might address multiple complications in patients with type 2 diabetes, and provide our thoughts on future directions in this field.

Overexpression of hepatic 5α-reductase and 11β-hydroxysteroid dehydrogenase type 1 in visceral adipose tissue is associated with hyperinsulinemia in morbidly obese patients

11-β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts cortisone to cortisol, mainly in the liver and visceral adipose tissue (VAT), and has been implicated in several metabolic disorders. The absence of systemic hypercortisolism in central obesity could be due to increased inactivation of cortisol to its tetrahydrometabolites by the hepatic enzymes 5α- and 5β-reductases. Our aim was to assess the expression of the reductases in the liver and of 11β-HSD1 in the liver and VAT in morbidly obese patients and to analyze their association with clinical, anthropometric, and biochemical parameters. Hepatic and VAT samples were obtained during bariatric surgery. 5α- and 5β-reductases, 11β-HSD1, and 18S expression was measured using real-time polymerase chain reaction. Anthropometric and biochemical variables were analyzed. Forty-one patients were recruited (age, 41.8 ± 10.6 years; body mass index, 42.1 ± 6.6 kg/m(2); 71% women). The expression of hepatic 5α- and 5β-reductases was positively correlated (r = +0.53, P = .004), and their expression levels were correlated with hepatic 11β-HSD1 expression (r = +0.61, P < .001 for 5α-reductase and r = +0.50, P < .001 for 5β-reductase). Hepatic 5α-reductase was associated with insulin (r = +0.34, P = .015). Visceral adipose tissue 11β-HSD1 expression was associated with glucose (r = +0.37, P = .025) and insulin (r = +0.54, P = .002). Our results showed that 5α-reductase and VAT 11β-HSD1 expressions were associated with insulinemia. These findings suggest that overexpression of 5α-reductase, through a higher inactivation of cortisol in the liver, could have a protective role in preserving hepatic sensitivity to insulin. The overexpression of liver reductases in obesity could be an adaptive response to an increase in cortisol production by the liver and visceral 11β-HSD1 to avoid systemic hypercortisolism.

A decrease in the dose of pegvisomant was needed for the treatment of acromegaly after adrenalectomy in a patient with coexisting preclinical Cushing's syndrome

We herein describe the case of a 47-year-old woman with pre-clinical Cushing's syndrome caused by a left adrenal adenoma, which was diagnosed 6 years after trans-sphenoidal selective removal of a pituitary adenoma for acromegaly at age 35. The patient was started on bromocriptine and then somatostatin analogues after the surgery; however, since her serum insulin-like growth factor-1 (IGF-1) values remained above the age-adjusted normal range, the treatment for acromegaly was switched from somatostatin analogues to pegvisomant (10 mg daily), before a left laparoscopic adrenalectomy. After the subsequent adrenalectomy, the dose of pegvisomant could be reduced gradually to once every 4 days without any increase in the serum IGF-1 values. This is the first report describing the need for a different dose of pegvisomant for the treatment of acromegaly before and after adrenalectomy for pre-clinical Cushing's syndrome.

Endocrinology of obesity

Obesity is a growing health concern in humans and companion animals. Obesity is highly associated with various endocrine abnormalities that are characterized by hormonal imbalance and/or resistance. Weight reduction generally normalizes these endocrine alterations, implicating obesity as a direct cause. Most data in this area have been derived from obese humans, with little data pertaining to hormonal changes in obese dogs and cats. Because the literature contains inconsistent results and because considerable hormone-hormone interactions occur, we have a limited understanding of the obesity-induced changes on the endocrine system in dogs and cats.

Reproductive axis function and gonadotropin microheterogeneity in a male rat model of diet-induced obesity

Obesity causes complex metabolic and endocrine changes that may lead to adverse outcomes, including hypogonadism. We herein studied the reproductive axis function in male rats under a high-fat diet and analyzed the impact of changes in glycosylation of pituitary LH on the bioactivity of this gonadotropin. Rats were fed with a diet enriched in saturated fat (20% of total calories) and euthanized on days 90 or 180 of diet. Long-term (180 days), high-fat feeding rats exhibited a metabolic profile compatible with insulin resistance and metabolic syndrome; they concomitantly showed decreased intrapituitary and serum LH concentrations, low serum testosterone levels, and elevated serum 17beta-estradiol concentrations. A fall in biological to immunological ratio of intrapituitary LH was detected in 180 days control diet-treated rats but not in high-fat-fed animals, as assessed by a homologous in vitro bioassay. Chromatofocusing of pituitary extracts yielded multiple LH charge isoforms; a trend towards decreased abundance of more basic isoforms (pH 9.99-9.0) was apparent in rats fed with the control diet for 180 days but not in those that were fed the diet enriched in saturated fat. It is concluded that long-term high-fat feeding alters the function of the pituitary-testicular axis, resulting in hypogonadotropic hypogonadism. The alterations in LH function found in these animals might be subserved by changes in hypothalamic GnRH output and/or sustained gonadotrope exposure to an altered sex steroid hormone milieu, representing a distinctly different regulatory mechanism whereby the pituitary attempts to counterbalance the effects of long-term obesity on reproductive function.

Growth hormone/insulin-like growth factor-I axis in obstructive sleep apnea syndrome: an update

Obstructive sleep apnea syndrome (OSAS) is a serious, prevalent condition that has significant mortality and morbidity when untreated. It is strongly associated with obesity and is characterized by changes in the serum levels or secretory patterns of several hormones. In particular, obese patients with OSAS show a peculiar reduction of both spontaneous and stimulated GH secretion coupled with reduced IGF-I concentrations and impaired peripheral sensitivity to GH. These endocrine abnormalities are more marked than those observed in non-apneic obese subjects, and are likely to be due to the effects of hypoxia and sleep fragmentation on hormone secretory pattern. The GH/IGF-I axis activity disruption can be responsible, at least in part, for metabolic alterations, which are common in OSAS and increase the risk of cardiovascular events as well as mortality. Effective assessment and management of OSAS may correct endocrine changes, improve quality of life, and prevent associated morbidity or death.

The associations between obesity, adipose tissue distribution and disease

Recent research has shown the marked differences in association with disease between obesity localized to the abdominal respectively to the gluteal-femoral regions. In this review systematic analyses were performed of the associations between obesity (body mass index, BMI) or abdominal obesity (increased waist-over-hip circumference ratio, WHR) on the one hand, and a number of disease end points, and their risk factors, as well as other factors on the other, WHR was associated with cardiovascular disease, premature death, stroke, non-insulin-dependent diabetes mellitus and female carcinomas. In contrast, BMI tended to be negatively correlated to cardiovascular disease, premature death, and stroke, but positively to diabetes. The established risk factors for these end points were found to correlate to WHR, while this was often not the case with BMI. BMI was positively correlated only to insulin, triglycerides and blood pressure. Together with diabetes mellitus, this seems to constitute a metabolic group of conditions which are thus associated with BMI. Androgens (in women), and perhaps cortisol, seem to be positively, and progesterone negatively correlated to WHR. The WHR was also positively associated with sick leave, several psychological maladjustments, psychosomatic and psychiatric disease. Attempts were made to interpret these findings. In a first alternative an elevation of FFA concentration, produced from abdominal adipose tissue, was considered to be the trigger factor for the pathologic aberrations associated with abdominal distribution of body fat. When obesity is added, the metabolic aberrations may be exaggerated. In a second alternative adrenal cortex hyperactivity was tested as the cause. When combined with the FFA hypothesis, this might explain many but not all of the findings. It seems possible to produce an almost identical syndrome in primates by defined experimental stress. Women with high WHR were found to have a number of symptoms of poor coping to stress. It was therefore suggested that part of the background to this syndrome might be a hypothalamic arousal syndrome developing with stress. It was concluded that obesity and abdominal distribution of adipose tissue constitute two separate entities with different pathogenesis, clinical consequences and probably treatment.

Catabolic effects of gastric bypass in a diet-induced obese rat model

PURPOSE OF REVIEW

In the USA, 8-10 million people are morbidly obese, which is associated with a high frequency of comorbidities. The most effective treatment is surgery. Of around 180,000 bariatric operations performed in 2005, 80% were Roux-en-Y gastric bypass, consisting of a small gastric pouch to minimize food intake and a Roux-en-Y of distal small bowel bypassing the upper gastrointestinal tract. The precise mechanisms whereby Roux-en-Y gastric bypass achieves sustained weight loss remain unknown. To gain insight into the catabolic events of sustained weight loss we developed a diet-induced obese Roux-en-Y gastric bypass rat model. We review our rat model data from the novel viewpoint of the catabolic state, comparing it with the limited human data available and the catabolic events occurring in cancer anorexia/cachexia syndrome.

RECENT FINDINGS

Current data suggest the involvement of mechanisms other than restrictive and malabsorptive factors of the Roux-en-Y gastric bypass, classically thought of as the mechanisms responsible for weight loss. Based on available data, gastrointestinal hormones and cytokines play a key role in reducing food intake and regulating energy homeostasis. Because of the cross talk between peripheral modulators and the hypothalamus, a critical role for their interaction in the outcome of Roux-en-Y gastric bypass is emerging.

SUMMARY

In our Roux-en-Y gastric bypass rat model many of the changes in gastrointestinal hormones, adipokines and cytokines as well as in hypothalamic neuropeptides and neurotransmitters resemble the changes observed in the anorexia/cachexia rat model, suggesting that Roux-en-Y gastric bypass triggers a catabolic state responsible for loss of appetite and prolonged body weight reduction.

Hypersensitivity of the corticotropic axis to the serotoninergic agent clomipramine in obese women

Serotoninergic control of food intake has been shown to be abnormal in obese persons with a decrease in serotoninergic tone. The neuroendocrine effects of intravenous I.V. administration of clomipramine (CMI), a serotonin uptake inhibitor, were studied in normal-weight (n=7) and obese subjects before (n=12) and after (n=6) dietary restriction. Under double-blind, placebo-controlled conditions, a single 12.5 mg dose of CMI was administered. There was no difference in baseline values of prolactin (PRL), corticotropin (ACTH) and cortisol in non-obese controls, obese before and obese after weight loss. CMI led to significant increases of PRL, ACTH, and cortisol concentrations in the controls as well as the obese group. The ACTH and cortisol responses to CMI in obese subjects were somewhat greater than the responses in normal-weight subjects. The area under the curve AUC for ACTH after clomipramine was 6202 +/- 976 pg/ml x 150 minutes for tile obese before weight loss and 3274 +/- 512 pg/ml x 150 minutes for the controls and the difference was significant at the level of p=0.052. The cortisol peak value after clomipramine was 163.71 +/- 14.31 ng/ml in the non-obese and 214.66 +/- 12.59 ng/ml in the obese (p=0.025). However, there was no difference in the obese subjects before and after weight loss. These data support the assumption that obese women have an abnormal sensitivity to the serotoninergic control of the hypothalamic pituitary adrenal axis (HPA), and that a mild weight loss does not significantly modify their serotoninergic tone.

A perspective on the hormonal abnormalities of obesity: are they cause or effect?

Studies in our laboratory and elsewhere have demonstrated numerous abnormalities of steroid and polypeptide hormone secretion in obesity: hyperestrogenemia and hypogonadotropic hypogonadism in obese men; diminished SHBG levels in both sexes; elevated free testosterone and free estradiol in obese women; PCOS-like gonadotropin and sex-hormone abnormalities in obese women; elevated serum insulin in both sexes; blunted stimulability of prolactin, growth hormone, and vasopressin in both sexes; and elevated basal levels and blunted stimulability and suppressibility of beta-endorphin in both sexes. All of these abnormalities have been clearly shown to be partly or completely reversible with weight loss, with the exception of the endorphin abnormalities. In that area, four out of the five studies reported show no reversibility with weight loss. Reversibility of nearly all the hormonal abnormalities of obesity (i.e., all but the hyperendorphinemia) by weight loss suggests that none of them is causative of obesity. Nevertheless, some of the reversible abnormalities may secondarily amplify the morbidity associated with obesity: the hyperinsulinemia may be related to the increased risk of hypertension, hyperlipidemia, coronary disease, and Type II diabetes; the elevated levels of free estradiol in obese women may be related to their increased risk of breast and endometrial cancer. The role of hyperendorphinemia in obesity clearly requires further investigation, since it is the only observed hormonal abnormality that appears to be non-reversible by weight loss, and also since there seems to be increased sensitivity to beta-endorphin in obesity. The possibility that endorphin abnormalities may be causal in obesity cannot be ruled out.

In vivo activity of 11beta-hydroxysteroid dehydrogenase type 1 and free fatty acid-induced insulin resistance

INTRODUCTION

Free fatty acids (FFAs) induce hepatic insulin resistance and enhance hepatic gluconeogenesis. Glucocorticoids (GCs) also stimulate hepatic gluconeogenesis. The aim of this study was to investigate whether the FFA-induced hepatic insulin resistance is mediated by increased activity of hepatic 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), accompanied by elevated hepatic cortisol levels.

METHODS

Following a 10-h overnight fast, six healthy male volunteers were investigated. A euglycaemic hyperinsulinaemic clamp was performed during lipid or saline infusion. To assess hepatic 11beta-HSD1 activity, plasma cortisol levels were measured after oral administration of cortisone acetate during lipid or saline infusion. In addition, 11beta-HSD activities were determined in vivo by calculating the urinary ratios of GC metabolites.

RESULTS

Lipid infusion increased FFAs (5.41 +/- 1.00 vs. 0.48 +/- 0.20 mmol/l; P < 0.005) and significantly increased insulin resistance [glucose infusion rate (GIR) 6.02 +/- 2.60 vs. 4.08 +/- 2.15 mg/kg/min; P < 0.005]. After lipid and saline infusions no changes in 11beta-HSD1 activity were found, neither by changes in cortisone acetate to cortisol conversion nor by differences in urinary free cortisol (UFF) or cortisone (UFE), 5beta-tetrahydrocortisol (THF), 5alpha-THF, cortisone (THE), UFF/UFE and (5alpha-THF + THF)/THE ratios.

CONCLUSIONS

We found no change in hepatic and whole-body 11beta-HSD1 activity during acute FFA-induced insulin resistance. Further studies are necessary to clarify whether 11beta-HSD1 in muscle and adipose tissue is influenced by FFAs and whether 11beta-HSD1 is involved in other conditions of insulin resistance.

Malnutrition and nonthyroidal illness syndrome after stroke

In the present study, nonthyroidal illness syndrome (NTIS), which is characterized by reduction of serum triiodothyronine (T3) without elevation of thyroid-stimulating hormone (TSH), was induced by protein-energy malnutrition (PCM). Protein-energy malnutrition is a common condition and is associated with worse clinical outcome in stroke patients admitted to a rehabilitation service. However, little is known about NTIS in stroke patients. Therefore, we studied the effects of PCM and NTIS on functional dependence in 51 stroke patients. We examined thyroid function by measuring serum free T3 (free T3), free thyroxine (free T4), and TSH. We estimated whether patients had mild NTIS (reduction of only free T3) or serious NTIS (reduction of both free T3 and free T4), examined PCM by measuring serum albumin, calculated body mass index (BMI) from weight and height on admission, and examined disability by obtaining the functional independence measurement (FIM). The 51 patients were divided into 2 groups according to FIM score on admission (low and high). The low-FIM group was divided into 2 subgroups according to the change in FIM score during hospitalization (improved or non-improved). Hypoalbuminemia was observed in 57% of patients, underweight in 22%, and mild NTIS in 82%; serious NTIS was not observed in any patients. Albumin and BMI were significantly higher in the high-FIM group than in the low-FIM group. Serum albumin concentration and BMI significantly positively correlated with free T3. Free T3 (but not albumin or BMI) was significantly higher in the improved subgroup than in the non-improved subgroup. Nonthyroidal illness syndrome after stroke was common and was provoked by PCM, which occurred in a high proportion of functionally dependent patients. It appears that, once stroke patients develop NTIS, it is difficult to achieve functional improvement. Therefore, during the recovery period after stroke, it is important to determine whether NTIS is present and ensure proper intensive rehabilitation and nutritional management.

Gene expression profiles post Roux-en-Y gastric bypass

BACKGROUND

The hypothalamus is involved in regulation of food intake (FI) and fat deposition. Molecular mechanisms of weight loss after Roux-en-Y gastric bypass (RYGB) were studied by correlating changes in gene expression profiles in hypothalamic arcuate nucleus (ARC) and subcutaneous abdominal fat (SAF).

METHOD

Diet-induced obese rats were divided into RYGB, sham-operated (SO-Obese), and sham-operated pair-fed (PF) groups. A non-obese group on a regular chow diet served as control. Body weight (BW) and FI were measured. Rats were killed 10 days after the operation. Plasma was analyzed for biochemical indices, ARC and SAF were analyzed for gene expression profiles. Body SAF was also weighed. Data were analyzed by ANOVA and factor analysis.

RESULTS

BW and FI decreased in RYGB versus SO-Obese, as reflected by decreased SAF (53%). Genes similarly expressed in ARC and SAF after RYGB were limited to several genes that predominantly related to metabolic pathways of carbohydrate, fat, neuropeptide, and cytokines. These expression profiles were similar to those seen in chow control and to those seen in a comparison of PF and SO-Obese.

CONCLUSIONS

RYGB-induced weight loss is associated with changes in gene profile expressions that could influence metabolic changes, contributing to weight loss.

Diet affects nutrient digestibility, hematology, and serum chemistry of senior and weanling dogs123

The objective of this experiment was to determine the effects of age and diet on serum chemistry, hematology, and nutrient digestibility in healthy dogs. Twelve senior (11 yr old; six males and six females) and 12 weanling (age = 8 wk old; six males and six females) beagles were randomly assigned to one of two dietary treatments: 1) an animal product-based (APB) diet or 2) a plant product-based (PPB) diet. The APB diet was primarily composed of brewer's rice, chicken by-product meal, and poultry fat, whereas the primary ingredients of the PPB diet included corn, soybean meal, wheat middlings, and meat and bone meal. Dogs remained on experiment for 12 mo. A 4-d total fecal collection was performed to determine apparent macronutrient digestibilities after 3 and 10 mo. Blood samples were collected at baseline and after 3, 6, 9, and 12 mo on study. After 3 mo, dogs fed the APB diet had greater (P < 0.001) DM (6 percentage units) and OM (7 percentage units) digestibilities than dogs fed the PPB diet. Senior dogs had greater DM (2.5 percentage units; P = 0.07) and OM (3 percentage units; P < 0.01) digestibilities than young dogs. Dogs fed the PPB diet had a lower (P < 0.001) fecal DM percentage (7.5 percentage units) and greater (P < 0.001) fecal output (253 vs. 97 g/d, as-is basis). After 10 mo, age did not affect nutrient digestibility or fecal characteristics. However, the effect of diet after 10 mo was similar to that observed after 3 mo, as dogs fed the PPB diet had a lower (P < 0.001) fecal DM percentage (7 percentage units), lower OM (4 percentage units; P = 0.09) and fat (6 percentage units; P < 0.001) digestibilities, and greater (P < 0.005) fecal output (235 vs. 108 g/d, as-is basis). At baseline, most serum metabolites were different between age groups, with weanlings having several metabolite concentrations outside the reference ranges for adult dogs. Blood cholesterol, red blood cells, hemoglobin, hematocrit, creatinine, total protein, albumin, bilirubin, sodium, chloride, and alanine transaminase were present in greater (P < 0.05) concentrations in senior dogs, but weanling dogs had greater (P < 0.05) concentrations of glucose, platelets, Ca, P, K, and alkaline phosphatase. Over time, blood cholesterol concentrations were affected by age (P < 0.05) and diet (P < 0.01). Senior dogs had greater (P < 0.05) cholesterol concentrations than weanling dogs. Moreover, dogs fed the APB diet had greater (P < 0.05) cholesterol concentrations than dogs fed the PPB diet. Overall, although serum metabolite concentrations of weanlings were different from senior dogs at baseline, as weanlings matured into young adults, metabolite concentrations were similar to those of senior dogs. Diet had the largest effects on nutrient digestibilities and fecal characteristics. Canine age and diet must be considered when interpreting experimental and clinical data.

Obese patients with obstructive sleep apnoea syndrome show a peculiar alteration of the corticotroph but not of the thyrotroph and lactotroph function

OBJECTIVE

Obstructive sleep apnoea syndrome (OSAS) is strongly associated with obesity (OB) and is characterized by several changes in endocrine functions, e.g. GH/IGF-I axis, adrenal and thyroid activity. It is still unclear whether these alterations simply reflect overweight or include peculiar hypoxia-induced hormonal alterations. Hormonal evaluations have been generally performed in basal conditions but we have recently reported that OSAS is characterized by a more severe reduction of the GH releasable pool in comparison to simple obesity. We aimed to extend our evaluation of anterior pituitary function to corticotroph, thyrotroph and lactotroph secretion under dynamic testing in OSAS in comparison with simply obese and normal subjects.

SUBJECTS AND METHODS

In 15 male patients with OSAS [age, mean +/- SEM 43.5 +/- 1.6 years; body mass index (BMI) 39.2 +/- 3.1 kg/m2; apnoea/hypopnoea index, (AHI) 53.4 +/- 8.7], 15 male patients with simple obesity (OB, age 39.7 +/- 1.2 years; BMI 41.2 +/- 2.0 kg/m2; AHI 3.1 +/- 1.2 events/h of sleep) and in 15 normal lean male subjects (NS, age 38.2 +/- 1.4 years; BMI 21.2 +/- 0.8 kg/m2; AHI 1.9 +/- 0.8 events/h of sleep) we evaluated: (a) the ACTH and cortisol responses to CRH [2 microg/kg intravenously (i.v.)] and basal 24 h UFC levels; (b) the TSH and PRL responses to TRH (5 microg/kg iv) as well as FT3 and FT4 levels.

RESULTS

Twenty-four-hour UFC levels in OSAS and OB were similar and within the normal range. Basal ACTH and cortisol levels were similar in all groups. However, the ACTH response to CRH in OSAS (Deltapeak: 30.3 +/- 3.8 pmol/l; DeltaAUC: 682.8 +/- 128.4 pmol*h/l) was markedly higher (P < 0.001) than in OB (Deltapeak: 9.3 +/- 1.4 pmol/l; DeltaAUC 471.5 +/- 97.3 pmol*h/l), which, in turn, was higher (P < 0.05) than in NS (Deltapeak: 3.3 +/- 0.9 pmol/l; DeltaAUC 94.7 +/- 76.7 pmol*h/l). On the other hand, the cortisol response to CRH was not significantly different in the three groups. Basal FT3 and FT4 levels as well as the TSH response to TRH were similar in all groups. Similarly, both basal PRL levels and the PRL response to TRH were similar in the three groups.

CONCLUSIONS

With respect to patients with simple abdominal obesity, obese patients with OSAS show a more remarkable enhancement of the ACTH response to CRH but a preserved TSH and PRL responsiveness to TRH. These findings indicate the existence of a peculiarly exaggerated ACTH hyper-responsiveness to CRH that would reflect hypoxia- and/or sleep-induced alterations of the neural control of corticotroph function; this further alteration is coupled to the previously described, peculiar reduction of somatotroph function.

Saturated free fatty acids, palmitic acid and stearic acid, induce apoptosis by stimulation of ceramide generation in rat testicular Leydig cell

In men, obesity has generally been associated with reduced plasma testosterone levels and with elevation of the plasma free fatty acids (FFAs). In this study, we investigated the effects of saturated FFAs including palmitic acid (PA) and stearic acid (SA), and polyunsaturated FFA arachidonic acid (AA) on the survival of rat testicular Leydig cell cultured in vitro. PA and SA markedly suppressed Leydig cell survival in a time- and dose-dependent manner. In contrast, AA stimulated the cell proliferation at 5-10 times of physiological concentration. The suppressive effect of PA and SA on cell survival was caused by apoptosis evidenced by DNA ladder formation and Annexin V-EGFP/propidium iodide staining of the cells. The apoptotic effect of PA was possibly mediated by ceramide generation because it could be completely blocked by ceramide synthase inhibitor fumonisin B1 and exogenous ceramide itself could directly induce apoptosis in vitro. Surprisingly, the apoptosis induced by PA could be partly prevented by AA. These results indicate that PA and SA induce apoptosis in testicular Leydig cells by ceramide production and these apoptotic effects may be a possible mechanism for reproductive abnormalities in obese men, and AA can partly prevent the apoptotic effect induced by saturated FFA.

Serum adrenal androgens in women with primary operable breast cancer and their relationship with age and body mass index

Several studies have found elevated levels of adrenal androgens in postmenopausal women and depressed levels in premenopausal women with breast cancer, suggesting a role for adrenal androgens in the aetiology of breast cancer. We have measured serum dehydroepiandrosterone sulphate and androstenedione in 81 women with primary operable breast cancer and 62 age-matched controls. Results showed that serum levels of both adrenal androgens fell significantly with age in women with breast cancer (P=0.003). However, no relationship was observed between serum adrenal androgen levels and body mass index in either women with breast cancer or controls. Dehydroepiandrosterone sulphate levels were elevated in postmenopausal women with breast cancer compared to controls, and this was not due to preoperative stress. No differences were observed in androstenedione levels between premenopausal or postmenopausal women with breast cancer and controls, nor were dehydroepiandrostenedione sulphate levels significantly different between premenopausal women with breast cancer and controls. These results suggest that dehydroepiandrosterone sulphate has a role in the aetiology of postmenopausal breast cancer.

11Beta-hydroxysteroid dehydrogenase type 1 in differentiating omental human preadipocytes: from de-activation to generation of cortisol

In humans, glucocorticoids are important regulators of adipose tissue distribution and function but circulating cortisol concentrations are normal in most patients with obesity. However, intracellular glucocorticoid levels can be modified by a microsomal enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) expressed mainly in the liver and adipose tissue. Locally generated cortisol within human adipose tissue can induce preadipocyte differentiation, but the relationship between 11beta-HSD1 expression and adipogenesis is unknown. Our present study has shown that in intact, undifferentiated omental (OM) but not subcutaneous (SC) preadipocytes, 11beta-HSD1 acts primarily as a dehydrogenase inactivating cortisol to cortisone. When preadipocytes become "committed" to adipocyte differentiation, oxo-reductase activity predominates generating cortisol. Since glucocorticoids are not only essential for OM preadipocyte differentiation but also inhibit cell proliferation, we postulate that 11beta-HSD1 dehydrogenase activity in "uncommitted" OM preadipocytes may provide an autocrine mechanism to protect preadipocytes from differentiation, in turn facilitating their proliferation. Once early differentiation is initiated, a "switch" to 11beta-HSD1 oxo-reductase activity generates cortisol, thus promoting adipogenesis. The differences in set-point of 11beta-HSD1 activity between OM and SC human adipose tissue may be an important factor in the pathogenesis of visceral obesity.

Glucagon administration elicits blunted GH but exaggerated ACTH response in obesity

Reduction in both spontaneous and stimulated GH secretion in obesity has been clearly demonstrated. Mild hyperactivity of hypothalamus-pituitary-adrenal (HPA) axis has been also reported. Glucagon, at least after im administration, induces clear increase in either GH or ACTH and F levels but its effect on somatotroph and corticotroph secretion in obesity has never been studied. In 7 patients with abdominal obesity (OB, aged 24-42 yr, BMI: 29.1-43.9 kg/m2, waist/hip ratio [WHR]: 0.86-1.00) we studied the GH, ACTH and F responses to the im administration of glucagon (0.017 mg/kg at 0 min). The results in OB were compared with those in a group of 6 age-matched controls normal subjects (Ns aged 26-32 yr, BMI 19.7-22.5 kg/m2). In Ns glucagon administration induced clear increase in GH (peak vs baseline, mean+/-SE: 11.6+/-3.4 vs 3.3+/-0.7 microg/l, p<0.02), and ACTH (52.9+/-15.2 vs 19.0+/-1.5 pg/ml, p<0.02) levels which peaked at +150 and +165 min, respectively. Increase in F levels (222.3+/-23.8 vs 158.3+/-7.0 ng/ml, p<0.05) was also recorded but peaked at +180 min. In OB glucagon administration induced GH response (7.4+/-2.3 vs 0.8+/-0.6 microg/l) lower (p<0.05) than that recorded in Ns; when the GH responses were evaluated by co-variance analysis, a significant difference between the 2 groups was recorded in term of peaks but not of AUCs. On the other hand, the ACTH response to glucagon in OB was higher than that in Ns (11452.6+/-2447.7 vs 4892.2+/-719.4 pg/ml x min, p<0.05). The F response to glucagon in OB and Ns was, however, similar (24057.9+/-4109.1 vs 29835.9+/-1566.0 ng/ml x min). In conclusion, this study demonstrates that in obese patients the im administration of glucagon elicits blunted GH response but exaggerated ACTH increase which is uncoupled with the adrenal response. These findings agree with the existence of concomitant GH insufficiency and altered corticotroph function in obesity.

Body mass index in relation to ovarian cancer: a multi-centre nested case-control study

The incidence of ovarian cancer is up to 10 times higher in Western countries than in rural Asia and Africa. One common consequence of a Western lifestyle is the development of excessive body weight and obesity. A multi-centre prospective study was conducted to investigate the association between body mass index (BMI) and ovarian cancer risk. A case-control study was nested within 3 prospective cohorts in New York (USA), Umeå (Sweden) and Milan (Italy). Information on anthropometry, demographic characteristics, medical history and lifestyle was obtained at the time of subjects' recruitment in each cohort. Women diagnosed with primary, invasive epithelial ovarian cancer from the 3 cohorts (n = 122) diagnosed 12 months or later after recruitment into the respective cohort served as case subjects. For each case subject, 2 control subjects that matched the case subject on cohort, menopausal status, age and date of recruitment were randomly identified. Data were analyzed by conditional logistic regression. There was an inverse association between BMI and ovarian cancer risk. For increasing quartiles of BMI above the lowest, the ORs were 0.62 (0.32-1.21), 0.59 (0.30-1.17) and 0.46 (0.23-0.92), p = 0.03. Analyses limited to women diagnosed 3 or more years after recruitment into the cohorts did not alter these findings. When obese women (BMI > 30) were compared to lean women (BMI < or = 23), the inverse association became stronger, with an OR of 0.38 (0.17-0.85), p < 0.02. There was some evidence of direct association of ovarian cancer with height, which was limited to cancers diagnosed before age 55. Our data suggest that increasing body weight may confer a protection against ovarian cancer.

A switch in dehydrogenase to reductase activity of 11 beta-hydroxysteroid dehydrogenase type 1 upon differentiation of human omental adipose stromal cells

As exemplified in patients with Cushing's syndrome, glucocorticoids play an important role in regulating adipose tissue distribution and function, but circulating cortisol concentrations are normal in most patients with obesity. However, human omental adipose stromal cells (ASCs) can generate glucocorticoid locally through the expression of the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) type 1 (11 beta-HSD1), which, in intact cells, has been considered to be an oxoreductase, converting inactive cortisone (E) to cortisol (F). Locally produced F can induce ASC differentiation, but the relationship between 11 beta-HSD1 expression and adipocyte differentiation is unknown. Primary cultures of paired omental (om) and sc ASC and adipocytes were prepared from 17 patients undergoing elective abdominal surgery and cultured for up to 14 d. Expression and activity of 11 beta-HSD isozymes were analyzed together with early (lipoprotein lipase) and terminal (glycerol 3 phosphate dehydrogenase) markers of adipocyte differentiation. On d 1 of culture, 11 beta-HSD1 activity in intact om ASCs exceeded oxoreductase activity in every patient (78.9 +/- 24.9 vs. 15.8 +/- 3.7 [mean +/- SE] pmol/mg per hour, P < 0.001), and in sc ASCs, relative activities were similar (40.6 +/- 12.2 vs. 36.9 +/- 8.8). Conversely, in freshly isolated om adipocytes, reductase activity exceeded dehydrogenase activity (23.6 +/- 1.5 vs. 6.2 +/- 0.8 pmol/mg per hour, P < 0.01). Following 14 d of culture in serum-free conditions with addition of 10 nM insulin (Ctr) or insulin with 100 nM F (+F), lipoprotein lipase/18S RNA levels increased in both the Ctr- and +F-treated ASCs, but glycerol 3 phosphate dehydrogenase increased only in the +F cultures. In both cases, however, 11 beta-HSD1 oxoreductase activity exceeded dehydrogenase activity (Ctr: 53.3 +/- 9.0 vs. 32.4 +/- 10.5, P < 0.05; +F: 65.6 +/- 15.6 vs. 37.1 +/- 11.5 pmol/mg per hour, P < 0.05), despite no significant changes in 11 beta-HSD1 mRNA levels. In sc ASCs, dehydrogenase activity was similar to reductase activity in both Ctr- and +F-treated cells. Type 2 11 beta-HSD expression was undetectable in each case. These data show that in intact, undifferentiated om ASCs, 11 beta-HSD1 acts primarily as a dehydrogenase, but in mature adipocytes oxoreductase activity predominates. Because glucocorticoids inhibit cell proliferation, we postulate that 11 beta-HSD1 activity in uncommitted ASCs may facilitate proliferation rather than differentiation. Once early differentiation is initiated, a "switch" to 11 beta-HSD1 oxoreductase activity generates F, thus promoting adipogenesis. Site-specific regulation of the set-point of 11 beta-HSD1 activity may be an important mechanism underpinning visceral obesity.

Central and peripheral glucocorticoid receptor function in abdominal obesity

Abdominal obesity seems to be associated with a moderately deranged feedback regulation of the hypothalamic-pituitary-adrenal (HPA) axis where central glucocorticoid receptors (GR) are involved. Therefore, functions of central and peripheral GR were compared in this study. Furthermore, since trinucleotide repeats in early exons of steroid hormone receptor genes influence transcription, and therefore may influence receptor density, this was also studied. Ten middle-aged men, 5 with abdominal obesity and 5 controls, were studied. The suppression of dexamethasone (dex) on serum cortisol was used in dose-response tests to assess the function of central GR. Abdominal adipose tissue biopsies were incubated and exposed to cortisol in different concentrations, and the function of the peripheral GR assayed as induction of lipoprotein lipase (LPL) activity. Aberrant expansion of exonic trinucleotide repeats in the first coding exon of the GR gene was studied by sequencing of genomic DNA. Results showed that men with abdominal obesity showed less inhibition of serum cortisol by dex, particularly at lower concentrations, while in the controls cortisol secretion was inhibited in an apparent dose-response manner. LPL activity in adipose tissue was lower in abdominal obese men than in controls. However, the sensitivity to cortisol was not different between the groups. There was no evidence for expansion of trinucleotide repeats. These results suggest that the central GR and the peripheral GR in adipose tissue exhibit functional differences in abdominal obesity.

Does obesity diminish the positive effect of oral contraceptive treatment on hyperandrogenism in women with polycystic ovarian syndrome?

Polycystic ovarian syndrome (PCOS) is an obvious indication for long-term treatment. Combined oral contraceptives (COC) remain the first choice for the treatment of hyperandrogenism in most patients. However, differences in endocrine and metabolic parameters between obese and lean patients have been postulated. This is the first study evaluating the effect of COC treatment in obese versus non-obese PCOS patients. In total, 28 lean [body mass index (BMI) <25 kg/m(2))] and 15 obese (BMI >30 kg/m(2)) women patients were enrolled in the study. The concentrations of androgens, sex hormone-binding globulin (SHBG) and lipids were measured before and after 6 months of treatment with COC containing low-androgenic progestins. Clinical androgenic symptoms were monitored. There was a lower concentration of SHBG in obese patients, but there were no differences in androgen concentrations between both groups before the study. Highly significant changes in concentrations of testosterone (P < 0.001), androstenedione (P < 0.0001), SHBG (P < 0.001) and LH (P = 0.01) were demonstrated in lean patients, with only less significant changes in SHBG (P < 0.01) and testosterone (P < 0.05) in obese patients during the study. Clinical androgenic symptoms improved significantly (P = 0.05) only in the group of lean women. No reduction in low-density lipoprotein-cholesterol/high-density lipoprotein-cholesterol ratio was observed in either group. In conclusion, the positive effect of COC treatment on androgen production, serum androgen binding capacity, and clinical androgenic symptoms was negatively influenced by an increased BMI.

Relationship of the metabolic syndrome and obesity to polycystic ovary syndrome: a controlled, population-based study

OBJECTIVE

Although hyperinsulinemia seems to be an essential feature of polycystic ovary syndrome, the frequency of gynecologic disorders related to polycystic ovary syndrome at a population level in women with evident metabolic syndrome is not known.

STUDY DESIGN

We conducted a cross-sectional, population-based study. Participants (N = 204) were recruited from a random sample of women in 5 age groups (range, 35-54 years) living in a defined area. Metabolic syndrome was considered to be present if 3 of the following 8 criteria were fulfilled: (1) first-degree relative with type II diabetes, (2) body mass index > or = 30 kg/m2, (3) waist/hip ratio > or = 0.88, (4) blood pressure > or = 160/95 mm Hg or drug treatment for hypertension, (5) fasting serum triglyceride level > or = 1.70 mmol/L, (6) high-density lipoprotein cholesterol value < 1.20 mmol/L, (7) abnormal glucose metabolism, and (8) fasting insulin value > or = 13.0 mU/L. The frequency of metabolic syndrome was 106 (19.5%) of 543 cases. The control group consisted of 62 overweight women without central obesity or metabolic syndrome and 53 healthy lean women (body mass index < 27 kg/m2.

RESULTS

The group with metabolic syndrome differed from the other women according to most of the selection criteria and also had the highest free testosterone concentration. However, there were no differences between the groups regarding parity, infertility problems, or obstetric outcome. However, oligomenorrhea appeared to be more common in women with metabolic syndrome, especially in those with more severe symptoms (46.2%), than in obese (25.4%) and lean (15.1%) control subjects. Polycystic-like ovaries were detected by vaginal ultrasonography with similar frequency (13.1%, 15.3%, and 13.2% in women with metabolic syndrome, obese women, and lean women, respectively).

CONCLUSIONS

Surprisingly few women with metabolic syndrome had symptoms suggestive of polycystic ovary syndrome, in comparison with obese and lean women. Our results suggest that at the population level polycystic ovary syndrome only accounts for a distinct subgroup of a much wider problem, metabolic syndrome.

Decreased androgen levels in massively obese men may be associated with impaired function of the gonadostat

OBJECTIVE

In obese men, sex hormone-binding globulin (SHBG) as well as total testosterone (TT) levels are decreased. Data concerning serum free testosterone (FT) levels in obese men are discordant. FT levels are decreased in only some morbidly obese men, consistent with an impairment of the feedback regulatory mechanism. In this study we aimed to verify serum levels of TT and FT in two groups of obese men (BMI < 35.0 kg/m2 and BMI > 35.1 kg/m2) before and after weight loss.

DESIGN

Two groups of obese men (group 1: BMI < or = 35 kg/m2; and group 2: BMI > or =35.1 kg/m2) were studied before and after 6 months of a low energy diet (1200 kcal/day). Every patient received a therapeutic prescription of dexfenfluramine (15 mg b.i.d.) that was maintained for 6 months.

SUBJECTS

Thirty-seven obese men and 20 normal weight men.

MEASUREMENTS

Serum sex hormones (TT and FT), serum luteinizing hormone (LH) and insulin were analyzed by RIA assays. Plasma insulin levels, serum TT, FT and LH concentrations were obtained before and after weight loss.

RESULTS

Moderately obese men (BMI = 32.3+/- 1.9 kg/m2) presented significantly decreased TT levels (390+/-120ng/dl) as well as FT (mean+/-s.d.:16.0+/-4.8pg/ml) as compared with normal controls. FT serum levels had a significant and negative correlation with body mass index (BMI), whereas for TT concentrations this correlation was not significant. Serum LH concentrations (4.5+/-2.9mlU/ml) were normal. Insulin levels were elevated in all patients (46.3+/-30.1 microU/ml). After weight loss there was a significant (P< 0.01) increase in TT, FT and LH levels, whereas insulin concentrations significantly decreased. In massively obese men (BMI = 43.0 6.7 kg/m2), TT (320+/-110ng/dl), FT (11.0+/-2.1 pg/ml) and LH (3.1+/-1.3mlU/ml) were decreased and significantly lower as compared with the previous group and normal controls. As expected, after weight loss TT, FT and LH levels increased significantly while insulin concentrations decreased.

CONCLUSIONS

We concluded that FT levels are dependent on the degree of obesity, massively obese men (BMI > or =35.1 kg/m2) being considered as candidates for consistently low FT levels. A functional decrease of LH pulse amplitude and serum LH levels as well as a possible negative action of excess of circulating leptin on the steroidogenesis may be related to the decreased androgens levels in massively obese men.

Effects of changes in body weight on carbohydrate metabolism, catecholamine excretion, and thyroid function

BACKGROUND

Weight gain and loss increases and decreases energy expenditure, respectively, out of proportion to changes in metabolic mass.

OBJECTIVE

We hypothesized that changes in energy expenditure associated with weight gain or loss were due in part to changes in catecholamine release, thyroid hormones, carbohydrate utilization, or a combination thereof.

METHODS

Urinary catecholamine excretion, serum thyroid hormone concentrations, and results of 3-h oral-glucose-tolerance tests were examined in obese and never-obese subjects at their usual weights, during weight loss or gain, and at stable weights 10-20% below or 10% above usual.

RESULTS

Urinary norepinephrine excretion decreased significantly during and after weight loss and increased during and after weight gain. Serum concentrations of reverse triiodothyronine increased significantly during and after weight loss, whereas serum concentrations of triiodothyronine increased significantly (by approximately 0%) during and after weight gain. Serum insulin and glucose concentrations during the oral-glucose-tolerance test increased significantly after weight gain in obese subjects. The percentage change in urinary norepinephrine excretion and in serum concentrations of triiodothyronine were significantly correlated with percentage changes in energy expenditure and with each other.

CONCLUSIONS

Changes in body weight were associated with changes in catecholamine excretion and thyroid hormones, which might-by virtue of the effects on energy expenditure-have favored a return to usual body weight. Weight gain induced more apparent insulin resistance in the obese than the never-obese subjects, suggesting a threshold effect of total body fat on this phenomenon.

Oral glucose tolerance testing but not intravenous glucose administration uncovers hyper-responsiveness of hypothalamo-pituitary-adrenal axis in patients with adrenal incidentalomas

OBJECTIVE

Modern imaging techniques are detecting adrenal incidentalomas with increasing frequency. Recent data suggests food-dependent hypercortisolism in a subgroup of patients with bilateral macronodular hyperplasia due to aberrant adrenal responsiveness to gastric inhibitory polypeptide (GIP). We studied the putative influence of food intake on the hypothalamo-pituitary-adrenal (HPA) axis in patients with adrenal incidentalomas and possible mediation by GIP.

PATIENTS AND MEASUREMENTS

We examined 15 mildly obese patients with adrenal incidentalomas, eight healthy, lean subjects, and seven obese patients with the metabolic syndrome, who were matched for body weight and age. Each individual underwent oral glucose tolerance testing (OGTT, 75 g glucose), i.v. glucose administration (IVGTT, 30 g glucose over 1 h) and i.v. glucose plus GIP infusion (body weight adapted leading to physiological postprandial GIP serum levels) on three occasions. Plasma glucose, ACTH and cortisol were measured from blood samples taken every 15 minutes from time - 30 minutes to + 75 minutes.

RESULTS

OGTT, i.v. glucose administration and GIP infusion led to comparable glucose values within the groups. In contrast to normal subjects and patients with the metabolic syndrome, patients with adrenal incidentalomas had significantly higher mean cortisol values after oral glucose intake as compared to i.v. glucose administration or GIP infusion. The increase in cortisol levels was preceded by a corresponding ACTH increase. No significant effect of GIP administration on cortisol or on ACTH secretion could be detected.

CONCLUSIONS

Patients with adrenal incidentalomas showed an abnormal responsiveness of the pituitary-adrenal axis to oral glucose administration. The cortisol peaks in these patients seemed to be ACTH-mediated and were not induced by GIP.

Low serum testosterone level as a predictor of increased visceral fat in Japanese-American men

OBJECTIVE

To examine the association between baseline testosterone levels and changes in visceral adiposity in Japanese-American men.

DESIGN

Prospective observational study.

SUBJECTS

Second-generation Japanese-American males enrolled in a community-based population study.

MEASUREMENTS

At baseline, 110 men received a 75g oral glucose tolerance test (OGTT), and an assessment of body mass index (BMI); visceral adiposity measured as intra-abdominal fat area (IAF) using computed tomography (CT); fasting insulin and C-peptide levels; and total testosterone levels. IAF was re-measured after 7.5 y. Subcutaneous fat areas were also measured by CT in the abdomen, thorax and thigh. The total fat (TF) was calculated as the sum of IAF and total subcutaneous fat areas (SCF).

RESULTS

After 7.5y, IAF increased by a mean of 8.0 cm2 (95% CI: 0.8, 15.3). Baseline total testosterone was significantly correlated with change in IAF (r= -0.26, P= 0.006), but not to any appreciable degree with change in BMI, TF, or SCF. In a linear regression model with change in IAF as the dependent variable, baseline testosterone was significantly related to this outcome while adjusting for baseline IAF, SCF, BMI, age, diabetes mellitus status (OGTT by the WHO diagnostic criteria) and fasting C-peptide (regression coefficient for baseline testosterone [nmol/l] = -107.13, P = 0.003).

CONCLUSIONS

In this Japanese-American male cohort, lower baseline total testosterone independently predicts an increase in IAF. This would suggest that by predisposing to an increase in visceral adiposity, low levels of testosterone may increase the risk of type 2 diabetes mellitus.

[The evaluation of the efficacy of a multidisciplinary treatment in a group of obese patients with a BMI > or = 35 and a change in lung function]

OBJECTIVE

To assess the efficacy of an interdisciplinary protocol for treating obesity in a group of patients with BMI > or = 35 and with altered respiratory function that was not necessarily related to obesity or not.

PATIENTS AND METHOD

Forty obese individuals between 18 and 60 years of age with altered respiratory function were enrolled. Spirometric values, plethysmograph volumes, arterial blood gases, and nighttime respiratory polygraphs were recorded. Following psychological and nutritional evaluation, the patients commenced year-long treatment for obesity involving a personalized diet and psychological counseling. Follow-up was weekly and individualized at first; in later sessions, patients were grouped. Lung function tests were repeated after loss of 5 kg. Sleep polygraphy was repeated after loss of 10 kg.

RESULTS

Weight loss over 15 kg was achieved by 48.6% of the patients. Respiratory function variables: FVC, FEV1, RV, ERV, PaO2 and SatO2 after treatment changed significantly from initial levels. Significant differences were also seen in the severity of sleep apnea and pressures needed for continuous positive airway pressure. Uric acid, glucose and triglyceride blood levels became normal in 89%, 61% and 50% of the patients, respectively, after weight loss. No characteristic psychological profile was identified for severe obesity, although levels of anxiety, eating behavior, marital adjustment and perception of body image were aspects that were fundamentally altered.

CONCLUSIONS

In the difficult group of obese patients with BMI > or = 35, interdisciplinary treatment has proven effective for achieving substantial weight loss, while improving respiratory function and severity of sleep disorder. This therapy, which is at present viable for few centers, deserves consideration in the interest of benefiting the increasing number of obese patients.

A função gonadal do homem obeso

Em homens obesos, os níveis séricos de globulina ligadora de hormônios sexuais (GLHS), bem como de testosterona total, (TT) estão diminuídos. Dados relativos aos níveis séricos de testosterona livre (TL) são controversos. Homens com obesidade mórbida apresentam valores plasmáticos de testosterona livre diminuídos, levando à alteração dos mecanismos de retro-regulação. O decréscimo funcional da amplitude do pulso de LH, bem como a diminuição dos níveis de LH, seriam a causa do hipoandrogenismo. Estudamos dois grupos de homens obesos: Grupo 1 (IMC <FONT FACE=Symbol>£</FONT> 35kg/m²) e Grupo 2 (IMC > ou = 35kg/m²) antes e após seis meses de dieta hipocalórica (1.200Kcal/dia). Todos os pacientes utilizaram dexfenfluramina (15mg 2x ao dia) durante todo o período do estudo. Níveis plasmáticos de insulina, bem como valores séricos de testosterona total, testosterona livre e LH foram dosados antes e após a perda de peso. Pacientes com obesidade moderada (IMC = 32,3 ± 1,9kg/m²) apresentaram diminuição significativa na concentração sérica de TT (390 ± 120ng/dL), bem como de TL (média ± DP 16,0 ± 4,8pg/mL) quando comparados a normais. A concentração de LH sérico (4,5 ± 2,9mlU/mL) foi considerada normal. Níveis de insulina mostravam-se elevados em todos os pacientes (46,3 ± 30,1miU/mL). Após a perda de peso, notou-se aumento significante (p < 0,01) dos níveis séricos de LH, TT e TL concomitante à queda da concentração de insulina plasmática. Em homens com obesidade de grande porte (IMC = 43,0 ± 6,7kg/m²), os níveis de TT (320 ± 110ng/dL), TL (11,0 ± 2,1pg/mL) e LH (3,1 ±1,3mlU/mL) mostraram-se significativamente menores quando comparados ao Grupo 1 e aos controles normais. Como esperado, após a perda de peso, os níveis séricos de TT, TL e LH aumentaram significativamente enquanto a concentração plasmática de insulina diminuiu. Concluímos que os níveis de TL são dependentes do grau de obesidade: homens com obesidade de grande porte (IMC > ou = 35kg/m²) são considerados como candidatos a apresentarem baixos valores séricos de TL.

The insulin resistance syndrome and the binding capacity of cortisol binding globulin (CBG) in men and women

BACKGROUND

Both insulin resistance and cortisol binding globulin (CBG) capacity have been found to correlate with plasma free fatty acid (FFA) concentration.

OBJECTIVE

To examine the changes in CBG binding with varying degrees of insulin resistance and plasma FFA levels.

SUBJECTS AND METHODS

Anthropometric parameters, serum cortisol levels, plasma CBG, CBG binding and insulin sensitivity (using the frequently sampled intravenous glucose tolerance test with minimal model analysis) were measured in a group of 38 healthy subjects (19 men, mean age 36.2 +/- 1.9; body mass index (BMI) 28.8 +/- 1.2, range 22.2-35.7), and 19 women, age 34.9 +/- 1.4; BMI 28.1 +/- 0.8, range 19-37.9)].

RESULTS

Plasma CBG levels did not differ between men and women. In men, CBG binding was associated with several parameters of the insulin resistance syndrome, including area under the curve for glucose during an oral glucose tolerance test (MBG, r = 0.45, P = 0.04), fasting insulin (r = 0.66, P = 0. 002), plasma triglycerides (r = 0.75, P < 0.0001), VLDL-triglycerides (r = 0.59, P = 0.007), fasting FFA (r = 0.72, P = 0.002), uric acid (r = 0.57 (P = 0.01) and insulin sensitivity (SI, r = - 0.58, P = 0.008). Free cortisol (estimated as the ratio of cortisol to CBG) was not associated with waist-to-hip ratio (WHR) or parameters of insulin sensitivity. In contrast to men, CBG binding was not associated with MBG, fasting insulin, plasma triglycerides, VLDL-triglycerides, FFA, uric acid or SI (all P = NS) in women. Serum free cortisol, however, correlated positively with WHR (r = 0. 62, P = 0.02) and negatively with SI (r = - 0.68, P = 0.01) in obese women. A multiple linear regression to predict CBG binding was constructed, with plasma CBG concentration and insulin sensitivity as independent variables. In this model, only SI entered the equation at a statistically significant level (P = 0.0012) contributing to 52% of the variance in CBG binding in men. When plasma FFA levels were added to the model, both SI (P = 0.04) and FFA levels (P = 0.039) contributed to 66% of the variance of CBG binding in men. In women, both plasma CBG concentration (P = 0.0005) and insulin sensitivity (P = 0.047) entered the equation at a statistically significant level, contributing to 60% of the variance in CBG binding. When plasma FFA levels were added to the model, only plasma CBG concentration (P = 0.043) was found to significantly contribute to 38% of the variance in CBG binding. The latter finding suggests that FFA levels constituted a confounding variable in the association between SI and CBG binding in women.

CONCLUSIONS

Both plasma free fatty acid and insulin sensitivity influence cortisol binding globulin binding capacity in men. Whether cortisol binding globulin binding is a factor implicated in the pathophysiology of insulin resistance or represents an adaptative tool in this situation awaits further studies.

Leptin and androgens in male obesity: evidence for leptin contribution to reduced androgen levels

Leptin circulates in plasma at concentrations that parallel the amount of fat reserves. In obese males, androgen levels decline in proportion to the degree of obesity. Recently, we have shown that in rodent Leydig cells leptin inhibits hCG-stimulated testosterone (T) production via a functional leptin receptor isoform; others have found that leptin inhibits basal and hCG-induced T secretion by testis from adult rats. In this study, we further investigated the relationship linking leptin and androgens in men. Basal and hCG-stimulated leptin and sex hormone levels were studied in a large group of men ranging from normal weight to very obese (body mass index, 21.8-55.7). Initial cross-sectional studies showed that circulating leptin and fat mass (FM) were inversely related with total and free T (r = -0.51 and r = -0.38, P < 0.01 and P < 0.05, respectively). Multiple regression analysis indicated that the correlation between leptin or FM and T was not lost after controlling for SHBG and/or LH and/or estradiol (E2) levels and that leptin was the best hormonal predictor of the lower androgen levels in obesity. Dynamic studies showed that in obese men the area under the curve of T and free T to LH/hCG stimulation (5000 IU i.m.) was 30-40% lower than in controls and inversely correlated with leptin levels (r = -0.45 and r = -0.40, P < 0.01 and P < 0.05, respectively). Also, LH/hCG-stimulation caused higher increases in 17-OH-progesterone to T ratio in obese men than in controls, whereas no differences were observed between groups either in stimulated E2 levels or in the E2/T ratio. In all subjects, the percentage increases from baseline in the 17-OH-progesterone to T ratio were directly correlated with leptin levels or FM (r = 0.40 and r = 0.45, P < 0.01), but not with E2 or other hormonal variables. In conclusion, our studies, together with previous in vitro findings, indicate that excess of circulating leptin may be an important contributor to the development of reduced androgens in male obesity.

Circulating levels of free insulin-like growth factors in obese subjects: the impact of type 2 diabetes

BACKGROUND

Obese subjects show major abnormalities in the growth hormone (GH)/insulin-like growth factor (IGF) system. Furthermore, they are prone to develop Type 2 diabetes, but the impact of diabetes plus obesity on the GH/IGF system remains unknown.

METHODS

We compared overnight fasting serum levels of free and total (extractable) IGF-I and -II, IGF-binding protein (IGFBP) -1, -2 and -3, and the high affinity GH-binding protein (GHBP) in matched groups of lean subjects (n=26) and obese subjects without (n=24) and with (n=29) Type 2 diabetes. Two groups (n=7) of healthy and Type 1 diabetic subjects were also studied.

RESULTS

Non-diabetic obese subjects had increased free IGF-I and -II, total IGF-II, IGFBP-3 and GHBP, reduced IGFBP-1 and -2 (p<0.05), but normal total IGF-I, when compared to lean subjects. In obese Type 2 diabetics free IGF-I was insignificantly reduced by 9% (p=0.3), when compared to non-diabetic obese subjects. However, the concentration was not significantly elevated when compared to that of lean controls (p=0.13). Also IGFBP-1 and total IGF-I were normal in obese Type 2 diabetics, whereas free and total IGF-II and IGFBP-3 remained elevated to a similar extent as in simple obesity (p<0.05). In contrast, GHBP was further increased and IGFBP-2 further reduced in obese Type 2 diabetics (p<0.05). In Type 1 diabetics total IGF-I and -II, and IGFBP-3 were normal. In contrast, free IGF-I and -II and GHBP were markedly reduced, whereas IGFBP-1 and -2 were increased (p<0.05).

CONCLUSIONS

Simple obesity was associated with marked changes in the GH/IGF system. Many of these abnormalities were unaffected by the concomitant presence of Type 2 diabetes (total IGF-I, free and total IGF-II and IGFBP-3). However, some changes became accentuated (GHBP and IGFBP-2), while others (free IGF-I and IGFBP-1) were no longer present. Notably, the impact of Type 1 diabetes on the GH/IGF system was clearly different from that of Type 2 diabetes.

Assessment of GH/IGF-I axis in obesity by evaluation of IGF-I levels and the GH response to GHRH+arginine test

The GH response to provocative stimuli in obese is often as low as in panhypopituitaric patients with severe GHD; however, IGF-I levels are normal or slightly reduced. In 53 patients with simple obesity (11 M and 42 F, age: 40.3+/-1.6 yr, BMI: 39.1+/-1.0 Kg/m2), we evaluated the GH response to GHRH (1 microg/kg iv)+arginine (ARG, 0.5 g/kg iv), and total IGF-I levels. The mean (+/-SE) GH peak after GHRH+ARG was markedly lower (74% reduction, p<0.0001) in obese (16.8+/-2.0 microg/l) than in normal subjects (62.7+/-4.3 microg/l). IGF-I levels in obese patients (134.0+/-7.6 microg/l) were lower (33% reduction, p<0.001) than in normal subjects (200.8+/-5.7 microg/l). Taking into account the 3rd centile limit of normal response, the GH response to GHRH+ARG was reduced in 62.3% (33/53) of the obese patients, and 21.2% (7/33) of them had low IGF-I levels. Assuming the 1st centile limit, it was reduced in 33.9% (18/53) obese subjects, and 22% (4/18) of them had low IGF-I levels. Considering 3.0 microg/L as arbitrary cut-off, the GH response was reduced in 5.7% (3/53) of the obese patients, and still one of them had low IGF-I levels. Our findings: a) confirm that the secretory capacity of somatotroph cells is often deeply impaired in obesity; b) demonstrate that IGF-I assay generally rules out severe impairment of GH/IGF-I axis in obese patients with marked reduction of the GH secretion; c) indicate that the percentage of obese patients with concomitant reduction of GH secretion and IGF-I levels is not negligible. Thus, IGF-I assay should be routinely performed in obese patients; those presenting with low IGF-I levels should undergo further evaluation of their hypothalamo-pituitary function and morphology, particularly in the presence of empty sella.

Neuroendocrine control of growth hormone secretion

The secretion of growth hormone (GH) is regulated through a complex neuroendocrine control system, especially by the functional interplay of two hypothalamic hypophysiotropic hormones, GH-releasing hormone (GHRH) and somatostatin (SS), exerting stimulatory and inhibitory influences, respectively, on the somatotrope. The two hypothalamic neurohormones are subject to modulation by a host of neurotransmitters, especially the noradrenergic and cholinergic ones and other hypothalamic neuropeptides, and are the final mediators of metabolic, endocrine, neural, and immune influences for the secretion of GH. Since the identification of the GHRH peptide, recombinant DNA procedures have been used to characterize the corresponding cDNA and to clone GHRH receptor isoforms in rodent and human pituitaries. Parallel to research into the effects of SS and its analogs on endocrine and exocrine secretions, investigations into their mechanism of action have led to the discovery of five separate SS receptor genes encoding a family of G protein-coupled SS receptors, which are widely expressed in the pituitary, brain, and the periphery, and to the synthesis of analogs with subtype specificity. Better understanding of the function of GHRH, SS, and their receptors and, hence, of neural regulation of GH secretion in health and disease has been achieved with the discovery of a new class of fairly specific, orally active, small peptides and their congeners, the GH-releasing peptides, acting on specific, ubiquitous seven-transmembrane domain receptors, whose natural ligands are not yet known.

Plasma growth hormone secretion is impaired in obesity-prone rats before onset of diet-induced obesity

Sprague-Dawley rats, which become obese (obesity prone) when fed a moderately high-fat (MHF; 32.5% of kcal as fat) diet, have decreased growth hormone (GH) concentrations compared with obesity-resistant rats fed the same diet. To determine whether plasma GH concentrations are different in obesity-prone rats compared with obesity-resistant rats before diet-induced obesity occurs, total integrated GH concentrations were determined in male Sprague-Dawley rats before exposure to the MHF diet. After initial blood sampling, rats were fed an MHF diet for 15 wk, over which time the animals were separated into two discrete populations based on body weight gain. Analysis of GH in episodic blood samples showed that the obesity-prone group had a GH secretion deficit before the onset of obesity (115.2 +/- 12.9 ng . ml-1 . 200 min-1) compared with obesity-resistant rats (237.2 +/- 47.1 ng . ml-1 . 200 min-1). The GH concentration difference was due to a decrease in mean GH peak height in rats that later became obese (34.8 ng/ml) compared with rats that remained lean (74.2 ng/ml). The results suggest that GH secretion impairment exists before dietary challenge or onset of obesity and may contribute to the susceptibility to obesity observed in these animals.

Serum concentrations of insulin, insulin-like growth factor(IGF)-I, IGF binding protein (IGFBP)-1 and -3 and growth hormone binding protein in obese children: fasting IGFBP-1 is suppressed in normoinsulinaemic obese children

OBJECTIVE

Simple obesity is characterized by normal or accelerated growth in the presence of reduced serum levels of GH, whereas its detailed mechanism remains unknown. We, therefore, evaluated interrelationships among serum levels of insulin, IFG-I, IGF binding protein (IGFBP)-1 and -3 and growth hormone binding protein (GHBP) in prepubertal obese children.

SUBJECTS

Prepubertal 20 obese children and 20 age-matched control children were included in the study.

RESULTS

Serum levels of insulin, IGF-I and IGFBP-3 in obese children did not differ from those in controls. The serum level of IGFBP-1 was significantly lower in obese children (22.1 +/- 18.4 micrograms/l, P < 0.001) than in control children (76.0 +/- 62.9 micrograms/l). No relationship was found between the serum levels of insulin and IGF-I, IGFBP-1, or IGFBP-3 in obese subjects. The serum level of GHBP in obese children was significantly elevated as compared with that in controls and was positively correlated with body mass index (BMI). No relationship was found between the serum levels of GHBP and IGF-I in obese subjects.

CONCLUSIONS

The present study showed for the first time that the fasting IGFBP-1 level was suppressed in prepubertal obese children with fasting normoinsulinaemia. We speculate that the hyperinsulinaemia which cannot be detected in the fasting state may have suppressed hepatic production of IGFBP-1. Alternatively, the reduced IGFBP-1 is likely to be a compensatory response to impaired insulin sensitivity. Thus, the IGFBP-1 level may be a useful predictor for the early identification in the development of insulin resistance in prepubertal obese children.

Long-term drug treatment of obesity in a private practice setting

This study evaluated the long-term efficacy and safety of the combination of phentermine and fenfluramine for the treatment of obesity in a private practice setting. A total of 1388 consecutive, qualified patients presenting to a private general internal medicine practice in Charlotte, NC, were enrolled with eligibility criteria including: age 18 years to 60 years, 20% over "desirable" bodyweight or body mass index > 27, no serious medical or psychiatric disease, and no contraindications to drug therapy. Patients were instructed in diet, exercise, and behavior modification techniques and received phentermine (15 mg/day to 30 mg/day) and fenfluramine (20 mg/day to 60 mg/day) continuously for over 3 years. Average duration of treatment was 15.9 months, and average weight loss at the last visit was 11.6 kg, or 11.7% of initial bodyweight. For patients completing 1 year of drug treatment, mean weight loss was 16.5 kg, or 16% of initial weight. Weight loss persisted for 2 years, but partial regain was seen at 3 years. The dropout rates were 18% at 6 months, 39% at 1 year, 68% at 2 years, and 78% at 3 years. At 1 year, blood pressure of hypertensive patients fell from 151/95 mm Hg to 127/78 mm Hg, and serum cholesterol and triglycerides of hyperlipidemic patient fell by 0.750 mmol/L (29 mg/dL) and 0.937 mmol/L (83 mg/dL), respectively. Adverse events were modest. We conclude that, in a private practice setting, long-term treatment of obesity with the combination of phentermine, fenfluramine, and a weight maintenance program is generally safe and effective. More research is needed to determine efficacy and safety for longer than 3 years.

Influences of obesity and weight loss on thyroid hormones. A 3-3.5-year follow-up study on obese subjects with surgical bilio-pancreatic by-pass

The effects of changing body size, energy intake and substrate oxidation on serum T4, FT4, T3, FT3 and TSH were investigated in ten morbidly obese subjects (4 men/6 women; age: 37 +/- 6 years; BMI: 53.8 +/- 6.5 kg/m2; mean +/- SD) who had undergone a surgical bilio-pancreatic by-pass in order to reduce their body weight. The starting value of serum FT3 was inversely related to the BMI (r = -0.63; p < 0.05). After 1-3 months, all the subjects were losing weight and their intake of carbohydrates was almost negligible; at this time a significant reduction of T3 (-14.6%; p < 0.0001), T4 (-19.5%; p < 0.0001), and FT3 (-10.5%; p < 0.001) was observed. Nine to 16 months after surgery, all the subjects were still losing weight, although there was no carbohydrate restriction; T3, T4, and FT3 were lower than prior to surgery but were beginning to increase. Finally, after 36-42 months the body weight of all the patients had been stable for at least the previous six months (final BMI: 32.9 +/- 4.1) and their body composition, as assessed by bio-impedance, was almost normal; only the concentrations of FT3 proved to be significantly lower than the basal value (-11.2%; p < 0.03). The change in FT3 proved to be independently influenced by the degree of fat malabsorption but not by changes in any of the physical characteristics considered. All values were always in the normal range; FT4 and TSH did not change significantly during the whole period of study. The final concentrations of TSH proved to be independently related to the postabsorptive protein oxidation (g/24h) (TSH = 2.37-0.018* protein oxidation). These results would suggest that nutritional factors have some influence on the blood levels of thyroid hormones, especially of FT3, while the removal of obesity does not seem to have any independent effect in the long-run.

Serum levels of insulin-like growth factor-I and insulin-like growth factor binding protein-3 in obese children

Growth hormone (GH) and insulin-like growth factor-I (IGF-I) metabolism may be disturbed in obese children. We investigated serum GH, IGF-I, IGF-binding protein-3 (IGFBP-3) levels in 42 obese and 40 non-obese healthy children aged 6-14 years. GH stimulation tests with L-dopa and insulin were performed. Serum IGF-I levels were studied by immunoradiometric assay (IRMA) and IGFBP-3 levels by radioimmunoassay (RIA). IGF-I levels were significantly higher in the obese group (p < 0.05), but IGFBP-3 levels were not different from the control group. IGF-I and IGFBP-3 levels were significantly higher in the obese pubertal children than in the obese prepubertal ones (p < 0.05). A positive linear correlation was found between body mass index (BMI) and IGF-I levels (r = 0.51, p < 0.05). These results suggest that obesity may have a considerable effect on IGF-I.