Prolactin and insulin ultradian secretion and adipose tissue lipoprotein lipase expression in severely obese women after bariatric surgery

Prolactin effects on the pathogenesis of diabetes mellitus

BACKGROUND

Prolactin (PRL) is a pituitary hormone promoting lactation in response to the suckling reflex. Beyond its well-known effects, novel tissue-specific and metabolic functions of PRL are emerging.

AIMS

To dissect PRL as a critical mediator of whole-body gluco-insulinemic sensitivity.

METHODS

PubMed-based search with the following terms 'prolactin', 'glucose metabolism', 'type 2 diabetes mellitus', 'type 1 diabetes mellitus', 'gestational diabetes mellitus' was performed.

DISCUSSION

The identification of the PRL-glucose metabolism network poses the basis for unprecedented avenues of research in the pathogenesis of diabetes mellitus type 1 or 2, as well as of gestational diabetes. In this regard, it is of timely relevance to define properly the homeostatic PRL serum levels since glucose metabolism could be influenced by the circulating amount of the hormone.

RESULTS

This review underscores the basic mechanisms of regulation of pancreatic β-cell functions by PRL and provides a revision of articles which have investigated the connection between PRL unbalancing and diabetes mellitus. Future studies are needed to elucidate the burden and the role of PRL in the regulation of glucose metabolism and determine the specific PRL threshold that may impact the management of diabetes.

CONCLUSION

A careful evaluation and context-driven interpretation of PRL levels (e.g., pregnancy, PRL-secreting pituitary adenomas, drug-related hyper- and hypoprolactinemia) could be critical for the correct screening and management of glucometabolic disorders, such as type 1 or 2 as well as gestational diabetes mellitus.

Improved Insulin Secretion Response and Beta-cell Function Correlated with Increased Prolactin Levels After Laparoscopic Sleeve Gastrectomy in Morbidly Obese Patients with Acanthosis Nigricans

OBJECTIVE

To explore insulin secretion patterns, β-cell function, and serum prolactin (PRL) concentrations in Chinese morbidly obese patients with Acanthosis nigricans (AN) and their alterations after laparoscopic sleeve gastrectomy (LSG).

METHODS

A total of 138 morbidly obese subjects undergoing LSG were categorized as simple obesity without AN (OB group, n = 55) and obesity with AN (AN group, n = 83). Oral glucose tolerance test (OGTT), PRL, and related metabolic indices were performed pre- and 12 months post-LSG. Insulin secretion patterns were derived from insulin secretion peak time during OGTT: type I (peak at 30 or 60 min) and type II (peak at 120 or 180 min).

RESULTS

Preoperatively, AN group showed significantly higher proportions of type II insulin secretion pattern, fasting insulin (FINS), and homeostatic model assessment of insulin resistance (HOMA-IR) whereas lower oral glucose insulin sensitivity (OGIS), insulinogenic index (IGI), and disposition index (DI) than OB group, which were improved significantly at 12 months postoperatively in both groups, more pronounced in AN group. Intriguingly, serum PRL declined substantially in AN group than OB group at baseline whereas elevated only in the AN group post-LSG. After adjusting for confounding factors, elevated PRL correlated significantly with increased IGI and DI, and decreased HOMA-IR in both genders, as well as increased OGIS in females, which was detected only in the AN group CONCLUSION: Morbidly obese patients with AN presented delayed insulin secretion response, impaired insulin secretion, and β-cell dysfunction, which were significantly improved by LSG and might benefit from elevated PRL.

Hyperprolactinemia in the postmenopause: versions and contraversions

The prevalence of hyperprolactinemia in postmenopausal women is unknown and has been estimated as infrequent by many studies. Prolactinomas found after menopause are usually macroadenomas and remain unrecognized for a long time due to atypical clinical signs or their absence. The growth potential of prolactinomas persists after menopause, most of them are invasive and accompanied by high prolactin levels. Treatment with dopamine agonists is usually long-term, the goals of which are to reduce tumor size, normalize prolactin levels and the negative effects of hyperprolactinemia. Treatment with cabergoline makes it possible to achieve remission of the disease in the first years after discontinuation, however, the proportion of relapses in postmenopausal women increases 5 years after discontinuation of the drug. Remission of prolactinomas is not evident in postmenopausal women. The modern management of patients with prolactinoma and/or hyperprolactinemia does not have clear positions in the postmenopausal period. Controversial issues remain: an ambiguous relationship between prolactin levels and breast cancer, there are no convincing conclusions on the improvement of bone mineral density and/or a decrease in the risk of fractures with normalization of prolactin levels, there are no data on metabolic parameters after the end of treatment with dopamine agonists, conflicting information about the relationship of prolactin levels and the severity of the manifold manifestations of the climacteric syndrome. The use of estrogen-progestin drugs in women with hyperprolactinemia/prolactinomas is also not well understood. Thus, the problem of hyperprolactinemia in the perimenopausal and postmenopausal period is underestimated and requires additional research, as well as the development of diagnostic and therapeutic strategies for potential benefits in terms of weight loss, improving insulin sensitivity, reducing the risk of fractures, maintaining sexuality and psycho-emotional well-being.

Glucose-Lipid Metabolism in Obesity with Elevated Prolactin Levels and Alteration of Prolactin Levels After Laparoscopic Sleeve Gastrectomy

PURPOSE

We investigated the differences in metabolism between obesity with or without increased prolactin (PRL) and the change in PRL after laparoscopic sleeve gastrectomy (LSG).

METHODS

Patients were divided into two groups: obesity with normal PRL (NP, n = 123) and high PRL (HP, n = 108). Glucose-lipid metabolism and inflammation were measured. A total of 115 patients with obesity (NP, n = 64; HP, n = 51) underwent LSG were recruited, and PRL was measured at 12 months after LSG.

RESULTS

(1) Blood glucose (BG), total cholesterol (TCH), LDL, triglyceride, and TNF-α were lower in the HP than in the NP group in the cross-sectional study (all P < 0.05). (2) PRL was negatively associated with neck circumference, waist-to-hip ratio, systolic blood pressure, heart rate, basal metabolism rate (BMR), ALP, TCH, and LDL in all subjects. PRL levels were positively associated with weight, HC, and BMR in males but were negatively associated with ALT, AST, ALP, BG 30 min, BG 60 min, FFA, and TCH in females (all P < 0.05). (3) Regression analysis showed that PRL negatively correlated with ALP and LDL-C in the whole baseline (β = - 0.051, P = 0.002; β = - 1.372, P = 0.033). PRL was a negative factor for ALP in females and a positive factor for BMR2 in males (β = - 0.099, P = 0.041; β = 0.005, P = 0.006). (4) PRL decreased in the HP group and increased in the NP group at 12 months post-operation (all P < 0.05). Increased PRL was associated with a change in TCH in the NP group (P < 0.05).

CONCLUSION

Increased PRL resulted in improved glucose-lipid metabolism and chronic low-grade inflammation. LSG led to increased PRL in NP and decreased PRL in HP. Improved lipid was associated with increased PRL in NP after surgery.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR-OCS-12002381.

TarGo: network based target gene selection system for human disease related mouse models

Genetically engineered mouse models are used in high-throughput phenotyping screens to understand genotype-phenotype associations and their relevance to human diseases. However, not all mutant mouse lines with detectable phenotypes are associated with human diseases. Here, we propose the “Target gene selection system for Genetically engineered mouse models” (TarGo). Using a combination of human disease descriptions, network topology, and genotype-phenotype correlations, novel genes that are potentially related to human diseases are suggested. We constructed a gene interaction network using protein-protein interactions, molecular pathways, and co-expression data. Several repositories for human disease signatures were used to obtain information on human disease-related genes. We calculated disease- or phenotype-specific gene ranks using network topology and disease signatures. In conclusion, TarGo provides many novel features for gene function prediction.

Metabolic profile and prolactin serum levels in men with type 2 diabetes mellitus: Old-new rubric

Background:

Prolactin (PRL) is involved in the regulation of glucose metabolism since high PRL serum levels are associated with low incidence of type 2 diabetes mellitus (T2DM). Therefore, the aim of the present study was to assess the metabolic effects of PRL on glucose homeostasis in men with T2DM.

Methods:

Eighty male patients with T2DM compared with 25 male healthy controls matched with patients for age and weight were divided into four groups: Group (A): patients with T2DM on metformin (n = 29), Group (B): patients with T2DM on glyburide (n = 30), Group (C): patients with T2DM on glyburide plus metformin (n = 21), and Group (D): healthy male subjects as control (n = 25). Body mass index (BMI) and blood pressure measurements were determined. Fasting blood glucose (FBG), glycated hemoglobin, total cholesterol, triglyceride (TG), high-density lipoprotein, low-density lipoprotein, atherogenic index, fasting serum insulin, insulin resistance (IR), and β-cell function of the pancreas were determined by homeostatic model assessment-2 (HOMA-IR). Furthermore, C-reactive protein and PRL serum level were determined in patients with T2DM and healthy control men.

Results:

BMI of T2DM patients was higher as compared with control (P = 0.003). Combination therapy (glyburide plus metformin) in patients with T2DM showed better effect on most of glycemic indices and lipid profile than glyburide or metformin monotherapy (P < 0.05). PRL serum level was higher in patients with T2DM as compared with control (P = 0.001). PRL serum level was high in glyburide-treated patients as compared with metformin-treated patients (P = 0.002).

Conclusion:

This study concludes that elevated PRL serum level in patients with T2DM is associated with diabetic complications. Diabetic pharmacotherapy mainly metformin reduced PRL serum level in patients with T2DM through amelioration of IR.

An investigation of the association between the level of prolactin in serum and type II diabetes

As a hormone secreted from the pituitary gland, prolactin (PRL) plays an important role in increasing beta cell proliferation, stimulating the secretion of insulin, preventing the activities of caspases on pathways that cause apoptosis in the Langerhans' islands, and moderating the immune system in regulating the whole body's sensitivity to insulin. Therefore, PRL level changes in type II diabetes and it can be concluded that PRL can play an important role in metabolic disorders of glucose. The present study is carried out in order to investigate the association between serum levels of PRL and type II DM. Blood samples were taken from 64 females affected by type II diabetes and 70 healthy ones, whose PRL level was measured using electrochemiluminescence (ECL) technique. It was a case-control study, and based on the definition dedicated to each group, subjects were assigned to two groups. The patient group included the subjects with type II diabetes while the control group included healthy samples. Data were analyzed using SPSS software (Mann-Whitney test, t-test, and spearman's rho correlation test). According to the results, PRL concentration in the serum of people affected by type II diabetes (5.32 ± 0.36) was significantly (P˂0.05) lower than that of control group (18.38 ± 2.3). The results also showed that in type II diabetes, the level of PRL changes so that the concentration of PRL in the serum of the patients was lower than that of healthy ones. Therefore, PRL concentration in the blood can be related to diabetes.

Decreased beta-cell function in breastfeeding obese and non-obese women: A prospective observational study

BACKGROUND & AIMS

Obesity is associated with lower breastfeeding rates. The underlying pathophysiological mechanisms are not well-understood, but there is increasing evidence on an association between parameters of maternal glucose metabolism and prolactin concentrations. In this cross-sectional observational study we investigate the relationship between breastfeeding, maternal obesity, and maternal glucose metabolism postpartum with beta cell function as a primary outcome measure.

METHODS

We investigated 106 women (44% obese) prospectively recruited during the pregnancy, who underwent a 75 g - 2 h oral glucose tolerance test (OGTT) between the 3rd and 5th months postpartum. At this time point, we tested the relationship between breastfeeding status, maternal prolactin concentrations, maternal obesity, and fasting and dynamic indices of glucose metabolism using multivariate logistic regression in a post hoc analysis of prospective observational data.

RESULTS

During the study visit at a mean of 122 (SE 9.3) days after delivery, 47% of obese women and 68% of non-obese women were breastfeeding (p < 0.05). Lactation and higher prolactin concentrations were associated with lower prepregnancy weight and lower postpartum insulin concentrations. Prehepatic beta-cell function was decreased in both obese (mean (SD); 0.16 (0.04) vs. 0.19 (0.05), p < 0.05) and non-obese (0.12 (0.05) vs. 0.16 (0.06), p < 0.01), lactating women. Obese lactating women have significantly lower first (1135.1 (306.7) pmol/L vs. 1517.3 (475.8) pmol/L, p < 0.01) and second phase insulin secretion (mean (SD), 300.2 (70.7) pmol/L vs. 393.1 (115.5) pmol/L, p < 0.01) as shown by Stumvoll indices when comparing to obese non-lactating women. Prehepatic beta-cell function and Stumvoll 1st phase insulin secretion index, but not BMI, were independently and negatively associated with breastfeeding and circulating prolactin concentrations.

CONCLUSIONS

Beta-cell function during lactation relates to breastfeeding and circulating prolactin concentrations independently of obesity. The well-known positive effects of lactation on maternal and offspring outcomes might reflect a causative relationship of higher breastfeeding rates in metabolically healthier women.

Decreased Levels of Circulating Cancer-Associated Protein Biomarkers Following Bariatric Surgery

BACKGROUND

Epidemiological studies have identified obesity as a major risk factor for cancer in humans, and trials have demonstrated a significant reduction in the incidence of cancer after bariatric surgery. The rapidity of weight loss after bariatric surgery provides an opportunity to identify the molecular changes associated with effective obesity treatment. Indirectly, this may provide some insights into the mechanisms that drive the association between obesity and cancer. We sought to measure circulating cancer-associated proteins before and after laparoscopic sleeve gastrectomy (LSG).

METHODS

We prospectively enrolled 15 patients undergoing LSG. Thirty-four plasma protein biomarkers thought to be associated with cancer processes were analyzed at baseline and following successful weight loss at 12 weeks using a multiplex bead-based assay.

RESULTS

Mean excess body weight loss was 44 % at 12-week follow-up. After LSG, a significant reduction in circulating plasma levels was observed for half (17/34) of the proteins assessed: VEGF-A, VEGF-C, VEGF-D, endoglin, PLGF, sFASL, IGFBP-1, IL-18, prolactin, EGF, TGFα, sCD40L, IL-18, TNFα, IL-6, HB-EGF, and PAI-1. Nonsignificant decreases were found for the remaining proteins.

CONCLUSIONS

Circulating cancer-related biomarker levels were reduced by surgical weight loss, and this benefit was achieved as early as 3 months after operation. The observed reduction in cancer biomarkers may be related to the reported decrease in cancer incidence following bariatric surgery.

Spanish consensus on the risks and detection of antipsychotic drug-related hyperprolactinaemia

INTRODUCTION

Iatrogenic hyperprolactinaemia (IHPRL) has been more frequently related to some antipsychotic drugs that provoke an intense blockade of dopamine D2 receptors. There is a wide variation in clinical practice, and perhaps some more awareness between clinicians is needed. Due to the high frequency of chronic treatment in severe mental patients, careful attention is recommended on the physical risk. IHPRL symptoms could be underestimated without routine examination.

METHODOLOGY

An intense scientific literature search was performed in order to draw up a multidisciplinary consensus, including different specialists of psychiatry, endocrinology, oncology and internal medicine, and looking for a consensus about clinical risk and detection of IHPRL following evidence-based medicine criteria levels (EBM I- IV).

RESULTS

Short-term symptoms include amenorrhea, galactorrhoea, and sexual dysfunction with decrease of libido and erectile difficulties related to hypogonadism. Medium and long-term symptoms related to oestrogens are observed, including a decrease bone mass density, hypogonadism, early menopause, some types of cancer risk increase (breast and endometrial), cardiovascular risk increase, immune system disorders, lipids, and cognitive dysfunction. Prolactin level, gonadal hormones and vitamin D should be checked in all patients receiving antipsychotics at baseline although early symptoms (amenorrhea-galactorrhoea) may not be observed due to the risk of underestimating other delayed symptoms that may appear in the medium term. Routine examination of sexual dysfunction is recommended due to possible poor patient tolerance and low compliance. Special care is required in children and adolescents, as well as patients with PRL levels >50ng/ml (moderate hyperprolactinaemia). A possible prolactinoma should be investigated in patients with PRL levels >150ng/ml, with special attention to patients with breast/endometrial cancer history. Densitometry should be prescribed for males >50 years old, amenorrhea>6 months, or early menopause to avoid fracture risk.

Importance of cannulated prolactin test in the definition of hyperprolactinaemia

PURPOSE

Recent guidelines suggest that a single prolactin measurement is adequate to confirm hyperprolactinaemia. This may lead to unnecessary investigation of artefactual hyperprolactinaemia. Prolactin measurement drawn from an indwelling cannula after rest removes stress as a confounding variable. The objective was to determine the frequency of true hyperprolactinaemia amongst patients referred following a single prolactin measurement.

METHODS

A cannulated study was considered if prolactin on referral ('Referral Prolactin') was <5,500 mU/L (260 ng/mL) but >410 mU/L (19 ng/mL) in males or >510 mU/L (24 ng/mL) in females, irrespective of clinical context. Case-notes of 267 patients undergoing cannulated prolactin measurement over a 10-year period (2000-2010) were reviewed. Pre-existing pituitary disease, dopamine antagonist use, and macroprolactinaemia were excluded. Morning ante-cubital vein cannulation was followed immediately by withdrawal of 'Repeat Prolactin' sample. After 120-min bed-rest, 'Resting Prolactin' was withdrawn through the cannula.

RESULTS

235 patients were included for analysis. 64 (27%) were within normal range; following Repeat Prolactin in 41 (17%) and Resting Prolactin in 23 (9%) cases. Referral Prolactin was higher in patients with true hyperprolactinaemia, 1,637 ± 100 mU/L (77.2 ± 4.7 ng/mL) than with artefactual hyperprolactinaemia, 1,122 ± 68 mU/L (52.9 ± 3.2 ng/mL; P < 0.001) but there was substantial overlap. 21 out of 171 cases (12%) with true hyperprolactinaemia had a macroadenoma. Presenting symptoms did not predict true hyperprolactinaemia. Referral Prolactin of 2,000 mU/L (94 ng/mL) had 97% specificity to identify true hyperprolactinaemia.

CONCLUSIONS

Reliance on a single, non-rested prolactin value may lead to over-diagnosis of hyperprolactinaemia. A resting sample should be considered with random values <2,000 mU/L (94 ng/mL).

Adipose tissue macrophages (ATM) of obese patients are releasing increased levels of prolactin during an inflammatory challenge: a role for prolactin in diabesity?

BACKGROUND

Obesity, characterized by low grade inflammation, induces adipose tissue macrophage (ATM) infiltration in white adipose tissue (AT) in both humans and rodents, thus contributing to insulin resistance. Previous studies have shown altered prolactin secretion in obesity, however, studies linking ATM infiltration and prolactin (PRL) secretion to the pathogenesis of the metabolic syndrome, obesity and diabetes are lacking.

METHODS/RESULTS

In vivo, qPCR and Western blot analysis demonstrated that prolactin expression was increased in AT of obese rats and also in human AT from obese, obese pre-diabetic and obese diabetic compared to lean counterparts. Immunohistochemistry of obese rat and human AT sections demonstrated a specific expression of prolactin in macrophages. In vitro, we demonstrated that hyperglycemia and inflammation stimulated macrophages (human THP-1 cell line and sorted rat ATM) to express PRL, when challenged with different glucose concentrations with or without IL1β. In in vivo and in vitro experiments, we assessed the expression of Pit-1 (PRL-specific transcription factor) and found that its expression was parallel to PRL expression.

CONCLUSIONS

In this study, we show that rodent and human macrophages synthesize prolactin in response to inflammation and high glucose concentrations.

GENERAL SIGNIFICANCE

Our data shed new light on the potential role of macrophages in the physiopathology of diabesity via the PRL expression and on its expression mechanism and regulation.

Prolactin in obese children: a bridge between inflammation and metabolic-endocrine dysfunction

OBJECTIVE

Adipocytes, regulated by insulin, represent the major peripheral source of prolactin (PRL), which play a pivotal role in energy balance, acting on adipogenesis and lipolysis. The aim of this study was to investigate whether PRL was associated with obesity-related inflammatory status and metabolic parameters. The diagnostic and prognostic role of PRL for metabolic syndrome (MS) was assessed. The effects of short-term lifestyle therapy on PRL levels were evaluated.

SUBJECTS

Prolactin was assessed in 94 obese patients and compared with 40 healthy children (HS).Patients were followed up for 1 year. Receiver operating characteristics (ROC) analysis was employed to find the best cut-off values capable of identifying MS in obese children for PRL, IL-6 and TNF-α. Kaplan-Meier curves were also generated. Adjusted risk estimates for MS were calculated using Cox proportional hazard regression analysis. An obesity intervention programme was administered for 12 months.

RESULTS

Prolactin levels were lower in obese patients than controls (P < 0·0001). PRL was found to be inversely correlated with BMI, IL-6 and HOMA-IR, whereas a direct correlation was found with HDL values. At ROC analysis, PRL showed higher sensitivity and specificity than IL-6 and TNF-α in identifying MS in obese children. Cox proportional hazard regression analysis showed that PRL predicted MS independently of other potential confounders. The lifestyle intervention improved PRL and metabolic parameters.

CONCLUSIONS

Prolactin represents a prognostic marker for obese children and a predictive factor for progression to MS. PRL measurement may be useful as part of the endocrine work-up of obese children.

Serum prolactin concentrations as risk factor of metabolic syndrome or type 2 diabetes?

BACKGROUND

To investigate potential associations of serum prolactin concentration (PRL) with metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), previously observed in small and selected study samples, in a large population-based cohort.

METHODS

Data from 3,993 individuals (2,027 women) aged 20-79 years from the population-based Study of Health of Pomerania (SHIP) were used to analyse cross-sectional and longitudinal associations of PRL with MetS and T2DM risk in age- and multivariable-adjusted Poisson regression models. PRL were log-transformed and modelled as continuous (per standard deviation (SD) increase) and categorical predictor (sex-specific quartiles) variable, separately for men and woman.

RESULTS

Cross-sectional analyses showed an inverse association between low PRL concentrations and prevalent T2DM risk in men and women after multivariable-adjustment (men: Q1 vs. Q4: relative risk (RR), 1.55; 95% confidence interval (CI), 1.13 - 2.14; women: Q1 vs. Q4: RR, 1.70; 95% CI, 1.10 - 2.62). Likewise, higher PRL concentrations were associated with significantly lower T2DM risk (RR per SD increase in log-PRL: 0.83; 95% CI, 0.72 - 0.95 in men, and 0.84; 95% CI, 0.71 - 0.98 in women, respectively). An inverse association between PRL and MetS risk was not retained after multivariable adjustment. Longitudinal analyses yielded no association of PRL with incident MetS or T2DM.

CONCLUSION

The present study is the first large population-based study reporting a cross-sectional inverse association between PRL and prevalent T2DM in both genders. But the absent longitudinal associations do not support a causal role of PRL as a risk factor of incident MetS or T2DM.

Insulin resistance and bariatric surgery

The objective of this article is to systematically review the changes in insulin resistance after various types of bariatric surgical procedures. A Pubmed and EMBASE search for studies measuring insulin resistance before and after bariatric surgery was done and all original research articles from 1980 to present (2011) were included. Only the currently widely performed bariatric procedures were included. A meta-analysis of change in HOMA-IR was conducted, grouping studies with similar duration of follow-up. The percentage decrease in HOMA-IR at <=2 weeks, 1 month, 3 months, 6 months, 12 months and >16-18 months was found to be (mean ± standard error) -33.48 ± 5.78, -46.43 ± 6.99, -38.79 ± 9.64, -58.62 ± 7.38, -44.91 ± 7.98 and -67.04 ± 10.78%, respectively. RYGB (gastric bypass) and BPD (biliopancreatic diversion) produced a significant decrease in insulin resistance at 2 weeks after surgery, while LSG (sleeve gastrectomy) was strongly trending. LSG produced an earlier decrease in insulin resistance when compared to LAGB (gastric banding). RYGB, BPD and LSG produce an early decrease in insulin resistance through yet unknown mechanisms.

Prolactin secretion in healthy adults is determined by gender, age and body mass index

Background

Prolactin (PRL) secretion is quantifiable as mean, peak and nadir PRL concentrations, degree of irregularity (ApEn, approximate entropy) and spikiness (brief staccato-like fluctuations).

Hypothesis

Distinct PRL dynamics reflect relatively distinct (combinations of) subject variables, such as gender, age, and BMI.

Location

Clinical Research Unit.

Subjects

Seventy-four healthy adults aged 22–77 yr (41 women and 33 men), with BMI 18.3–39.4 kg/m².

Measures

Immunofluorometric PRL assay of 10-min samples collected for 24 hours.

Results

Mean 24-h PRL concentration correlated jointly with gender (P<0.0001) and BMI (P = 0.01), but not with age (overall R² = 0.308, P<0.0001). Nadir PRL concentration correlated with gender only (P = 0.017) and peak PRL with gender (P<0.001) and negatively with age (P<0.003), overall R² = 0.325, P<0.0001. Forward-selection multivariate regression of PRL deconvolution results demonstrated that basal (nonpulsatile) PRL secretion tended to be associated with BMI (R² = 0.058, P = 0.03), pulsatile secretion with gender (R² = 0.152, P = 0.003), and total secretion with gender and BMI (R² = 0.204, P<0.0001). Pulse mass was associated with gender (P = 0.001) and with a negative tendency to age (P = 0.038). In male subjects older than 50 yr (but not in women) approximate entropy was increased (0.942±0.301 vs. 1.258±0.267, P = 0.007) compared with younger men, as well as spikiness (0.363±0.122 vs. 0463±2.12, P = 0.031). Cosinor analysis disclosed higher mesor and amplitude in females than in men, but the acrophase was gender-independent. The acrophase was determined by age and BMI (R² = 0.186, P = 0.001).

Conclusion

In healthy adults, selective combinations of gender, age, and BMI specify distinct PRL dynamics, thus requiring balanced representation of these variables in comparative PRL studies.

A morbid obese Japanese woman with a body mass index of 83.2 kg/m2: before and after sleeve gastrectomy

A 34-year-old Japanese woman presented at our institution weighing 182.7 kg, 148.2 cm tall, and with a body mass index of 83.2 kg/m(2). She had been overweight since childhood, but no abnormality was found to explain her obesity. Treatments, including mazindol, bofu-tsusho-san, dietary restriction, and BioEnterics Intragastric Balloon, did not result in improvement of her obesity. Finally, we performed sleeve gastrectomy, and she has maintained her weight within 130-140 kg without rebounding for 2 and a half years. We followed the clinical changes before and after the operation. This case provides potentially interesting information regarding operative treatment for morbid obesity in Japanese.

High fructose diets increase 11β-hydroxysteroid dehydrogenase type 1 in liver and visceral adipose in rats within 24-h exposure

The increased prevalence of overweight and obesity in the United States during the past three decades coincides with a trend of increased sugar intake, especially fructose, leading to speculation that the two trends may be linked. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), that regulates intracellular tissue-specific glucocorticoid levels, is increased in adipose and suppressed in liver of obese humans and animals. Hexose-6-phosphate dehydrogenase (H6PDH) is colocalized with 11β-HSD1 and generates nicotinamide adenosine dinucleotide phosphate, the required cofactor for 11β-HSD1 reductase activity that converts inert glucocorticoid metabolite into active hormone. We examined the acute effects of ad lib access to 16% solutions of sucrose, fructose, or glucose and chow and water. Diets high in fructose, but not glucose or sucrose increased 11β-HSD1 mRNA within 24 h in liver and adipose by greater than two- and threefold, respectively (P ≤ 0.05). After 1 week, hepatic 11β-HSD1 mRNA and protein were suppressed by >60% in all sugar-fed groups, a phenomenon not previously reported in the absence of obesity. Sucrose- and fructose-fed rats had higher plasma triglycerides than did control or glucose-fed rats at both 24 h and 1 week (P ≤ 0.02), consistent with previously reported effects of fructose on lipid metabolism. We conclude that high-sugar diets initiate glucocorticoid dysregulation associated with obesity prior to the onset of phenotypic changes, and that high fructose diets specifically induce changes in 11β-HSD1 within 24-h exposure.