Androgens and women's health: genetic and epidemiologic aspects of lipid metabolism

Hyperprolactinemia induced by hCG leads to metabolic disturbances in female mice

The metabolic syndrome is a growing epidemic; it increases the risk for diabetes, cardiovascular disease, fatty liver, and several cancers. Several reports have indicated a link between hormonal imbalances and insulin resistance or obesity. Transgenic (TG) female mice overexpressing the human chorionic gonadotropin β-subunit (hCGβ+ mice) exhibit constitutively elevated levels of hCG, increased production of testosterone, progesterone and prolactin, and obesity. The objective of this study was to investigate the influence of hCG hypersecretion on possible alterations in the glucose and lipid metabolism of adult TG females. We evaluated fasting serum insulin, glucose, and triglyceride levels in adult hCGβ+ females and conducted intraperitoneal glucose and insulin tolerance tests at different ages. TG female mice showed hyperinsulinemia, hypertriglyceridemia, and dyslipidemia, as well as glucose intolerance and insulin resistance at 6 months of age. A 1-week treatment with the dopamine agonist cabergoline applied on 5-week-old hCGβ+ mice, which corrected hyperprolactinemia, hyperandrogenism, and hyperprogesteronemia, effectively prevented the metabolic alterations. These data indicate a key role of the hyperprolactinemia-induced gonadal dysfunction in the metabolic disturbances of hCGβ+ female mice. The findings prompt further studies on the involvement of gonadotropins and prolactin on metabolic disorders and might pave the way for the development of new therapeutic strategies.

Gender Differences in the Association between Lipid Profile and Sexual Function among Patients with Coronary Artery Disease

BACKGROUND

Although several studies have been conducted on the association between lipid profile and sexual function among men with coronary artery disease, there is a paucity of knowledge about this association among women with coronary artery disease.

OBJECTIVES

Our study aimed to evaluate the link between lipid profile and sexual function in men and women with coronary artery disease.

METHODS

One hundred and twenty patients with documented coronary artery disease were consecutively sampled from an outpatient cardiovascular clinic. The patients were assessed for lipid profile and sexual relationship using the Relation and Sexuality Scale (RSS). In addition, the Hospital Anxiety and Depression Scale (HADS) was used to measure the symptoms of anxiety and depression. The characteristics of chest pain were also measured using the Rose Angina Questionnaire. The data were analyzed through linear regression analysis.

RESULTS

This study was conducted on 91 males (75.8%) and 29 females (24.2%). Multivariate analysis showed that low-density lipoprotein cholesterol was correlated with sexual function (B = 0.01, P = 0.010) and total sexual relationship (B = 0.01, P = 0.050). A correlation was also observed between the level of high-density lipoprotein and sexual frequency score (B = -0.02, P = 0.040). Gender moderated these correlations. Among males, serum cholesterol (r = 0.193, P = 0.047) and low-density lipoprotein (r = 0.224, P = 0.037) were correlated to sexual function. In females, however, low-density lipoprotein was correlated to the total sexual relationship (r = 0.426, P = 0.021) and high-density lipoprotein was correlated to sexual frequency (r = -0.334, P = 0.046).

CONCLUSIONS

The findings of this study showed a relationship between lipid profile and sexual relationship among both male and female patients with coronary artery disease. The link between lipid profile and sexual function of the patients with coronary artery disease is thus beyond just the effect of lipid profile on erectile dysfunction.

Effects of two different low-dose oral contraceptives on plasma homocysteine levels

OBJECTIVE

The aim of this study was to investigate the effects of two currently used low-dose combined oral contraceptives (COCs) (20 μg ethinyl estradiol [EE]/150 μg desogestrel [DSG] vs. 20 μg EE/100 μg levonorgestrel [LNG]) on plasma homocysteine levels.

METHODS

A total of 90 participants were enrolled in the study; 30 of them had not been using COC for at least 12 months prior to their enrollment, while 60 were on regular treatment within 12-18 months. Therefore, the control group consisted of 30 participants. Group DSG/EE consisted of 30 women and group LNG/EE consisted of 30 women. Serum samples of homocysteine profile were obtained during the early follicular phase.

RESULTS

Significantly lower serum homocysteine concentrations (Group DSG/EE: 7.2 +/- 1.3; Group LNG/EE: 9.1 +/- 3.2;

CONTROL GROUP

8.2 +/- 2.2; p<0.05) were observed in DSG/EE group compared to LNG/EE and control groups.

CONCLUSION

Although the decrease in homocysteine levels with 20 μg EE/150 μg DSG containing COC was statistically significant, the clinical relevance of our findings needs to be further investigated.

Hostility, testosterone, and vascular reactivity to stress: effects of sex

This study investigated the association of personality with cardiovascular stress reactivity (CVR) in men and women. Also, the degree to which testosterone and estradiol reactivity were related to personality and CVR measures was examined. Twenty-six men and 44 women completed the Cook-Medley Hostility Scale, the Beck Depression Inventory, and the Spielberger Trait Anxiety Inventory before speech, Stroop, and math stress. Testosterone (men) and estradiol (subset of women) were sampled once after an initial rest period and again after the last stressor. Cardiovascular reactivity, including cardiac output and total peripheral resistance (TPR), was assessed during stressors. For men, testosterone increased significantly with stress, and testosterone reactivity to stressors was significantly correlated with hostility. However, stepwise multiple regression revealed that hostility was the only independent predictor of CVR to speech, math, and Stroop stress in men, accounting for 13%-32% of the variance in TPR. Baseline systolic blood pressure explained 22% of the variance in TPR reactivity to speech preparation. No evidence was obtained to suggest that hostility, depressive mood, or anxiety predicted CVR in women, and estradiol did not show stress-sensitive effects. These data provide evidence that increased vascular reactivity may be one mechanism linking hostility to increased cardiovascular mortality in men and support the notion that hostility may have different implications for CVR in women.

Direct effects of sex steroid hormones on adipose tissues and obesity

Sex steroid hormones are involved in the metabolism, accumulation and distribution of adipose tissues. It is now known that oestrogen receptor, progesterone receptor and androgen receptor exist in adipose tissues, so their actions could be direct. Sex steroid hormones carry out their function in adipose tissues by both genomic and nongenomic mechanisms. In the genomic mechanism, the sex steroid hormone binds to its receptor and the steroid-receptor complex regulates the transcription of given genes. Leptin and lipoprotein lipase are two key proteins in adipose tissues that are regulated by transcriptional control with sex steroid hormones. In the nongenomic mechanism, the sex steroid hormone binds to its receptor in the plasma membrane, and second messengers are formed. This involves both the cAMP cascade and the phosphoinositide cascade. Activation of the cAMP cascade by sex steroid hormones would activate hormone-sensitive lipase leading to lipolysis in adipose tissues. In the phosphoinositide cascade, diacylglycerol and inositol 1,4,5-trisphosphate are formed as second messengers ultimately causing the activation of protein kinase C. Their activation appears to be involved in the control of preadipocyte proliferation and differentiation. In the presence of sex steroid hormones, a normal distribution of body fat exists, but with a decrease in sex steroid hormones, as occurs with ageing or gonadectomy, there is a tendency to increase central obesity, a major risk for cardiovascular disease, type 2 diabetes and certain cancers. Because sex steroid hormones regulate the amount and distribution of adipose tissues, they or adipose tissue-specific selective receptor modulators might be used to ameliorate obesity. In fact, hormone replacement therapy in postmenopausal women and testosterone replacement therapy in older men appear to reduce the degree of central obesity. However, these therapies have numerous side effects limiting their use, and selective receptor modulators of sex steroid hormones are needed that are more specific for adipose tissues with fewer side effects.

Effects of high carbohydrate and high fat diet on plasma metabolite levels and on i.v. glucose tolerance test in intact and neutered male cats

To elucidate the impact of dietary influence on carbohydrate and lipid metabolism and on the development of diabetes mellitus in the carnivorous cat, a 3 weeks feeding trial was carried out on six sexually intact and six neutered adult male cats. The effects of two isonitrogenic diets, differing in carbohydrate and fat content, were investigated on plasma metabolite levels in a 24-h blood sampling trial. Plasma leptin concentrations were also determined at the beginning and at the end of the 24-h trial. Glucose and insulin response was measured in an i.v. glucose tolerance test. A 5 days long digestion trial was also performed, which revealed a high digestion capacity of both fat and carbohydrates in cats. The high fat diet induced a significant rise in the plasma triglyceride, FFA, beta-hydroxybutyrate and cholesterol concentration, while the elevation in the glucose level did not reach significance. In the glucose tolerance test no significant difference was found between the neutered and intact cats. However, independently of the sexual state, the cats on the high fat diet showed a slightly elongated glucose clearance and reduced acute insulin response to glucose administration. This is indicative of diminished pancreatic insulin secretion and/or beta-cell responsiveness to glucose. The results of this preliminary study may be the impetus for a long-term study to find out whether it is rather the fat rich ration than carbohydrate rich diet that is expected to impair glucose tolerance and thus might contribute to the development of diabetes mellitus in cats. Whether the alteration in glucose metabolism is due to altered leptin levels remains to be determined.

Comparative effects of oral esterified estrogens with and without methyltestosterone on endocrine profiles and dimensions of sexual function in postmenopausal women with hypoactive sexual desire

OBJECTIVE

In some women, a decline in sexual interest accompanies a relative androgen insufficiency after menopause. We sought to characterize the hormonal effects of the combination of oral esterified estrogens and methyltestosterone and to investigate whether this regimen improves hypoactive sexual desire.

DESIGN

Double-blind randomized trial.

SETTING

Healthy volunteers in a multicenter research environment.

PATIENT(S)

Postmenopausal women taking estrogen therapy who were experiencing hypoactive sexual desire.

INTERVENTION(S)

4 months of treatment with 0.625 mg of esterified estrogens (n = 111) or the combination of 0.625 mg of esterified estrogens and 1.25 mg of methyltestosterone (n = 107).

MAIN OUTCOME MEASURES

Baseline and end-of-study measurements of total and bioavailable testosterone and sex hormone-binding globulin (SHBG), and mean change in level of sexual interest or desire as rated on the Sexual Interest Questionnaire.

RESULT(S)

Treatment with the combination of esterified estrogens and methyltestosterone significantly increased the concentration of bioavailable testosterone and suppressed SHBG. Scores measuring sexual interest or desire and frequency of desire increased from baseline with combination treatment and were significantly greater than those achieved with esterified estrogens alone. Treatment with the combination was well tolerated.

CONCLUSION(S)

Increased circulating levels of unbound testosterone and suppression of SHBG provide a plausible hormonal explanation for the significantly improved sexual functioning in women receiving the combination of esterified estrogen and methyltestosterone.

Relationship between insulin resistance, sex hormones and sex hormone-binding globulin in the serum lipid and lipoprotein profiles of Japanese postmenopausal women

The purpose of the present study was to investigate the relationship between insulin resistance, sex hormones and sex hormone-binding globulin (SHBG) in regard to the serum lipid and lipoprotein profiles of 82 Japanese postmenopausal women. A multiple regression analysis for lipids, lipoproteins, and apoproteins as dependent variables was performed. All regression models included the following variables as potential independent variables; BMI, percentage of body fat, waist-hip ratio, free testosterone (Free T) and SHBG. In addition, model A included insulin resistance evaluated by HOMA-R and model B included fasting insulin (FIRI). In model A, both Free T and HOMA-R were independent predictors of total-C (TC)/high-density lipoprotein-C (HDL-C) and low-density lipoprotein-C (LDL-C)/HDL-C. The BMI was independently associated with HDL-C. The Free T was a single independent predictor of TC and LDL-C. Both BMI and HOMA-R were independent predictors of triglyceride (TG). In addition, SHBG was also independently associated with apoprotein B (Apo B) and Apo B/Apo AI. In model B, FIRI was an independent predictor of lipid metabolism with similar results to those observed in model A. These results suggest that the lipid characteristics in postmenopausal women might be associated with insulin resistance and/or hyperinsulinemia, and relative hyperandrogenicity which thus induces an increase in the amount of Free T and a decrease in the SHBG within physiological ranges.

The medicalization of menopause: critique and consequences

Menopause is in the process of becoming medicalized. Midlife and older women are being told that natural menopause is actually a deficiency condition requiring replacement hormones to maintain health and increase longevity. The three major diseases that are being linked with the lower estrogen levels of midlife and older women are heart disease, osteoporosis and, most recently, Alzheimer's disease. Primary prevention of these diseases is the rationale used for urging healthy women to take long-term hormones. Although there have been many challenges to these links and warnings against the widespread use of hormones, they have been either ignored or trivialized. In this article, the author examines mortality and morbidity statistics across and within nations and over time, critiques the major arguments used to support the notion that menopause places women at an increased risk of disease and that exogenous hormones reduce this risk, and discusses the adverse consequences of defining all midlife and older women as hormonally deficient and in need of medical intervention.

Effects of two low-dose oral contraceptives containing ethinylestradiol and either desogestrel or levonorgestrel on serum lipids and lipoproteins with particular regard to LDL size

This study was designed to determine the effects of two low-dose oral contraceptives, most frequently given in our area, monophasic desogestrel/ethinylestradiol (DG/EE) and triphasic levonorgestrel/ethinylestradiol (LNG/EE), on lipoprotein parameters, especially LDL particle size and HDL subclass distribution (determined by lipid-stained 2%-20% polyacrylamide gradient gel electrophoresis) in 37 healthy normolipidemic women aged 19 to 27 years. Lipid and lipoprotein parameters were measured before the start of treatment and in the third month of oral contraceptive use. Results reflected the estrogen-progestin balance. As compared with baseline values, with both formulations, plasma total cholesterol, phospholipids, and HDL3 cholesterol increased, and LDL-predominant peak size decreased, with a translation of LDL pattern A towards pattern I. With DG/EE, plasma triglycerides, apolipoproteins AI and B increased. With LNG/EE, LDL cholesterol increased, and HDL2 cholesterol decreased. All these modifications were moderate, within threshold limits. Estrogen-dominant monophasic DG/EE appears to be more favorable than progestin-dominant triphasic LNG/EE, since the reduction in LDL-predominant peak size is not associated with an increase in LDL cholesterol or with a decrease in HDL2 cholesterol.

Gene structure and promoter for Crad2 encoding mouse cis-retinol/3alpha-hydroxysterol short-chain dehydrogenase isozyme

Cis-retinol/androgen dehydrogenase type 2 (CRAD2) has been shown to catalyze the dehydrogenation of retinols, including 9-cis retinol, and also to exhibit 3alpha- and 17beta- hydroxysteroid dehydrogenase activities. To examine the function of this enzyme and regulation of its gene, the Crad2 gene was cloned from a mouse genomic DNA library and characterized. The complete mouse CRAD2-coding region was found in four exons spanning an approximately 5kb region. The nucleotide sequences of the exons encoding 316 amino acids were identical to those of the previously reported mouse Crad2 cDNA. Primer extension analysis and RNase protection assay were used to map the major transcription initiation sites to the positions lying 87 and 89 base pairs upstream of the ATG translation start codon. The region proximal to the initiation sites exhibited the absence of both TATAA and CAAT boxes. This region had hepatocyte nuclear factor binding sites, consistent with its predominant expression in the liver. Computer analysis of an approximately 7.5kb 5'-flanking region also suggested the presence of binding sites for AP-1, SREBP1, HSF2, c-Rel, c-Myc, CREBP, GATA, Ets, E2F, and Oct-1, suggesting that various factors including retinoic acid, cholesterol, various kinds of stress, the cell cycle, and cyclic AMP may regulate the expression of this gene. Fluorescence in-situ hybridization analysis showed that Crad2 is located at the terminus of mouse chromosome 10, an area that corresponds to band 10D3, suggesting that RDH-related SDRs may be located together in the cluster locus. Northern blot hybridization and RT-PCR analysis demonstrated that CRAD2 was expressed not in early embryonic stages, and not in embryonic stem cells, but instead in the gastrointestinal tract during later embryonic development and adult stage. In conclusion, we have presented the first complete structural analysis, including that of the promoter and chromosomal location, of a member of the retinol/androgen dehydrogenase subfamily of the group of the short-chain dehydrogenase/reductase (SDR) isozymes. Our findings will provide the basis for in-vitro or in-vivo studies concerning the regulation of retinol and androgen metabolism and enable determination of the mechanism of diseases related to retinol, retinal, retinoic acid, and androgen.

The use of androgens in menopause

Recent increase in the potential role for androgen supplementation in the menopause, as well as the availability of nontraditional, over-the-counter food supplements containing DHEA, currently touted for postmenopausal health, have raised the need for clinicians to have a working knowledge of both potential benefits and risks of androgen replacement as a supplement to traditional hormone replacement therapy. There is compelling evidence that androgen levels are reduced after bilateral oophorectomy. The degree of androgen reduction after natural menopause may be less, and the onset of this decrease more gradual in this population. A decrease in androgen levels has been proposed as one etiology for decreased libido, and there is some evidence to support androgen use in oophorectomized women suffering from diminished libido. Such evidence is mixed, however, in naturally menopausal women. Androgen replacement may provide additional relief of menopausal symptoms in some patients, but this evidence is also inconsistent. Initial studies seem to support a perceived enhancement in psychological well-being, but confirmatory, long-term studies are still needed. Available evidence suggests a positive impact on bone density with the use of some androgen preparations, but no consistent benefit from DHEA has been demonstrated. Although androgen therapy can induce decreases in HDL cholesterol levels, the clinical impact of this is not yet known. Currently, there is little support for the routine use of androgen supplementation in the menopause. Additionally, a number of adverse events may be associated with androgen use. Careful patient selection, with comprehensive evaluation to sort out other possible medical or psychological conditions, should be undertaken before the initiation of androgen replacement. Currently available preparations are limited in number and flexibility in dosing, but there is ongoing effort to develop new delivery systems and therapeutics so that options available in the future may allow for enhanced availability and efficacy.

Prevention of development of dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in the rat by the new nonsteroidal antiestrogen EM-800 (SCH57050)

The effect of EM-800, a new non-steroidal antiestrogen having pure antiestrogenic activity, was studied on chemical carcinogenesis induced by dimethylbenz(a)anthracene (DMBA) as well as on serum lipids and bone mass in the rat. Treatment with EM-800 orally, once daily, for 282 days (9 months), starting 3 days before DMBA administration, decreased the incidence of tumors from 95% in control animals to 60% (p < 0.01), 38% (p < 0.01), and 28% (p < 0.01) at the daily doses of 25 microg, 75 microg, and 250 microg, respectively. The average number of tumors per animal decreased from 4.5 +/- 0.5 tumors in the control group to 0.9 +/- 0.2 (p < 0.01), 0.5 +/-0.2 (p < 0.01), and 0.3 +/- 0.1 (p < 0.01) tumors in the rats treated with the above-indicated doses of the anti-estrogen. In addition, treatment with the increasing doses of EM-800 reduced serum cholesterol levels to 64%, 56%, and 48% of control, while serum triglycerides decreased to 31%, 28%, and 30% of control. Bone mineral content (BMC) and bone mineral density (BMD) of total skeleton, femur, and lumbar spine were not significantly affected following 282 days of treatment with EM-800. However, treatment with EM-800 inhibited the urinary ratio of hydroxyproline to creatinine (HP/Cr) from 14.0 +/- 3.90 micromol/mmol in controls to 7.6 +/-0.8 (p < 0.05), 6.8 +/- 0.8 (p < 0.01), and 6.8 +/- 1.1 (p < 0.01) micromol/mmol, respectively, while the same treatment had no effect on serum total alkaline phosphatase (tALP) activity or urinary calcium and phosphorus excretion. The 25 microg, 75 microg, and 250 microg daily doses of EM-800 inhibited uterine weight by 35% (p < 0.01), 62% (p < 0.01), and 66% (p < 0.01), while vaginal weight was reduced by 8% (p < 0.05), 30% (p < 0.01), and 38% (p < 0.01), respectively. In agreement with the 27% increment (p < 0.05) in ovarian weight at the highest anti-estrogen dose used, serum androstenedione (p < 0.05), androst-5-ene-3beta,17beta-diol (p < 0.01), testosterone (p < 0.05), and estradiol (p < 0.01) levels were increased. The present data show that EM-800 prevents the development of DMBA-induced mammary tumors while simultaneously inhibiting uterine and vaginal weight, reducing serum cholesterol and triglyceride levels, and having no adverse effect on bone mass following 9 months of treatment in the rat.

The association of low plasma testosterone level with coronary artery disease in Chinese men

The incidence rate and mortality of coronary heart disease (CHD) is obviously higher in men than in women, which may be related to the influence of plasma lipoprotein metabolism by endogenous sex hormones. We determined plasma testosterone (TTT), estradiol, total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), HDL2-C, HDL3-C, apolipoprotein (Apo) AI, Apo B100 and lipoprotein (a) [Lp(a)] in 201 subjects, among them 102 patients with CHD and 99 healthy subjects. It was found that, mean plasma TTT levels in patients with CAD (252+/-125 ng/ml) was significantly lower than in the healthy subjects (412+/-309 ng/ml). There was a negative association between plasma TTT level and plasma TG level (r=-0.239; P<0.001) and Lp(a) (r=-0.163, P<0.05), and a positive association between plasma TTT level and HDL-C (r=0.301, P<0.001) and HDL3-C (r=0.328, P<0.001). The results in the present study suggest that low plasma TTT level may be a risk factor for CHD, which may relate to the influence of plasma lipoprotein metabolism by endogenous testosterone.