Nitrendipine treatment in women with polycystic ovarian syndrome: evidence for a lack of effects of calcium channel blockers on insulin, androgens, and sex hormone-binding globulin.

It has been shown that in vitro calcium channel blockers may regulate insulin secretion, and in vivo studies have demonstrated that they can reduce the degree of hyperinsulinemia and ameliorate the insulin-resistant state in subjects (particularly men) with obesity and hypertension. It is also commonly accepted that hyperinsulinemia may be an important factor responsible for the development of hyperandrogenism in obese women with polycystic ovarian syndrome (PCOS). We, therefore, investigated whether the administration of nitrendipine, a widely used calcium channel blocker, may improve both insulin levels and hyperandrogenism in a group of seven insulin-resistant hyperinsulinemic women with obesity and PCOS. They were treated for 7-8 days with oral nitrendipine (10 mg, twice daily) or placebo using a double blind, cross-over design. Before and after treatment, blood samples were obtained for androgen and sex hormone-binding globulin determinations, and an oral glucose tolerance test was performed, measuring glucose and insulin. Both nitrendipine and placebo failed to decrease basal and stimulated insulin levels. Moreover, no significant variations in testosterone, dehydroepiandrosterone sulfate, or sex hormone-binding globulin concentrations were observed after either treatment. Therefore, these data fail to support previous suggestions that calcium channel blockers may play a role in the treatment of hyperandrogenism and hyperinsulinemia in obese women with PCOS.

Insulin regulates testosterone and sex hormone-binding globulin concentrations in adult normal weight and obese men.

There are no studies in vivo on the effects of insulin on androgens and sex hormone-binding globulin (SHBG) in men. We, therefore, investigated the effects of insulin suppression on testosterone and SHBG in two groups of eight nondiabetic adult obese men and six healthy normal weight men who underwent diazoxide treatment (100 mg, three times daily) for 7 days. Blood samples for hormone determination were obtained before the subjects had been selected for the study, immediately before diazoxide administration, and on the last day of treatment. A 24-h oral glucose tolerance test was also performed for glucose, insulin, and C-peptide determinations before and on the last day of treatment. Only one subject experienced significant side-effects, and no significant changes in mean body weight were found during the treatment. Diazoxide administration worsened glucose tolerance in several subjects and reduced fasting and glucose-stimulated insulin levels by approximately 50% in both control and obese subjects. No significant difference was present between historical and pretreatment hormone values in either group. Moreover, there were no differences in pretreatment gonadotropin and SHBG concentrations between the two groups, whereas testosterone (free and total) levels were lower in the obese than in the control subjects. After diazoxide administration, testosterone (free and total) decreased slightly, but significantly, whereas LH and SHBG significantly increased in both groups. Diazoxide treatment increased estradiol levels in controls, but not in obese men. In conclusion, these results indicate that in vivo, insulin is capable of stimulating testosterone production and, simultaneously, of inhibiting SHBG concentrations in both normal weight and obese men.

Clinical and hormonal characteristics of obese amenorrheic hyperandrogenic women before and after weight loss.

We studied a group of obese hyperandrogenic amenorrheic women to determine the effects of weight loss on anthropometry, hormonal status, menstrual cycles, ovulation, and fertility. Fourteen women had polycystic ovaries, two the hyperandrogenism-insulin resistance-acanthosis nigricans syndrome, one hirsutism of adrenal origin, and three idiopathic chronic anovulation. The duration of amenorrhea before the study ranged from 3-17 months [mean, 8.6 +/- 4.5 (+/- SD)]. All women ate a hypocaloric diet for a period of 8.0 +/- 2.4 months. Weight loss ranged from 4.8 to 15.2 kg (mean, 9.7 +/- 3.1 kg; 1.35 +/- 0.56 kg/month) and the waist to hip ratio, which was used as a measurement of body fat distribution, decreased from 0.86 +/- 0.1 to 0.81 +/- 0.06 (P less than 0.0001). The women's mean plasma testosterone and LH concentrations decreased significantly (P less than 0.001 and P less than 0.005, respectively). A significant positive correlation was found between the decreases in plasma testosterone levels and the decreases in glucose-stimulated insulin levels. Moreover, the decreases in the waist to hip ratio correlated positively with the decreases in glucose-stimulated insulin levels and inversely with the decreases in plasma 17 beta-estradiol. No relationships were found between weight loss and the changes in plasma insulin, steroid, and gonadotropin concentrations. The responsiveness to the weight reduction program was evaluated by comparing the number of menstrual cycles during the study period with the number reported before it. Eight women had significantly improved menstrual cyclicity (responders), while 12 did not (nonresponders). The clinical characteristics and hormone values were similar in responder and nonresponder women. In the group as a whole, 33% of the menstrual cycles during the study were ovulatory, and 4 pregnancies occurred. Hirsutism improved significantly in more than half of the women, as did acanthosis nigricans when present. We conclude that weight loss is beneficial in all obese hyperandrogenic women regardless of the presence of polycystic ovaries, the degree of hyperandrogenism, and the degree and distribution of obesity.

The hypothalamic-pituitary-adrenal axis in obese women with different patterns of body fat distribution.

To investigate whether obese subjects with abdominal obesity may be characterized by hyperactivity of the hypothalamic-pituitary-adrenal axis, we examined two groups of obese women with a waist to hip ratio (WHR) lower than 0.80 (n = 13), therefore having peripheral body fat distribution (P-BFD), or a WHR higher than 0.85 (n = 12), thus having abdominal body fat distribution (A-BFD). A group of seven normal weight healthy women served as controls. All subjects underwent the following protocol study that included 1) measurement of daily urinary free cortisol excretion rate; 2) a CRF test (human CRF, 1 microgram/kg BW, as iv bolus), with blood samples taken at regular intervals for ACTH and cortisol determination; and 3) an ACTH test, performed by administering two boli of ACTH (Synacthen, 0.2 microgram/kg BW, iv), at 90-min intervals, with blood samples taken for cortisol determination. Each woman also had a control saline study. Basal levels of both ACTH and cortisol rose significantly after CRF administration in all groups, but this increase was significantly higher in A-BFD than in P-BFD and control women. A significant correlation was found between the incremental area of cortisol and that of ACTH during the CRF test (r = 0.502), but not between these parameters and WHR values. Although the cortisol increase after the ACTH test was higher in A-BFD than in the other groups, these differences were only significant at 60 min during the test and when the analysis for repeated measures was applied. On the contrary, the incremental cortisol area after the ACTH test was not significantly different in the three groups. Moreover, it was not significantly correlated with the incremental cortisol area after CRF test or WHR values. Daily urinary free cortisol excretion rates (per g creatinine), however, were significantly higher in A-BFD than in P-BFD and control women. These results, therefore, suggest that obese women with A-BFD may have hyperactivity of the hypothalamic-pituitary-adrenal axis. This abnormality could be central in origin, due to hypersecretion of CRF or ACTH; alternatively, it could represent an adaptive phenomenon secondary to a state of functional cortisol resistance.

Protein metabolism in obese patients during very low-calorie mixed diets containing different amounts of proteins and carbohydrates.

To assess long-term nitrogen sparing capacity of very low-calorie mixed diets, we administered two isoenergetic (2092KJ) liquid formula regimens of different composition for 8 weeks to two matched groups of massively obese patients (group 1: proteins 60 g, carbohydrate 54 g; group 2: proteins 41 g, carbohydrates 81 g). Weight loss was similar in both groups. Daily nitrogen balance (g) during the second month resulted more a negative in group 2 with respect to group 1. However, within the groups individual nitrogen sparing capacity varied markedly; only a few in group 1 and one in group 2 were able to attain nitrogen equilibrium throughout the study. Daily urine excretion of 3-methylhistidine fell significantly in group 1 but did not change in group 2. Unlike total proteins, albumins, and transferrin, serum levels of retinol-binding protein, thyroxin-binding globulin, and complement-C3 fell significantly in both groups but per cent variations of complement-C3 were more pronounced in the first group. Prealbumin levels fell persistently in group 1 and transiently in group 2. The results indicate that even with this type of diet an adequate amount of dietary protein represents the most important factor in minimizing whole body protein catabolism during long-term semistarvation in massively obese patients. Moreover, they confirm the possible role of dietary carbohydrates in the regulation of some visceral protein metabolism.

Heterogeneity of the erythrocyte Na-K pump status in human obesity.

The number of Na-K pump units, the Na-K-ATPase activity, the K transport turnover rate per pump unit and the intracellular Na and K concentrations were measured in the erythrocytes of 56 obese patients and 20 normal subjects. No differences were found between the two groups. In obese patients, we failed to observe any influence of dietary habits, age of onset, or family history of obesity on the Na pump status. On the other hand, we found that the number of pump units was not a close reflection of the membrane cation transport and in some patients with an abnormally high number of pump units, an inappropriately low Na-K-ATPase activity was observed. We also identified two small groups of obese patients with, respectively, abnormally high or low K transport turnover rate per pump unit. Our study seems to support the hypothesis that abnormalities in the erythrocyte Na-K pump system are not usual in the obese population but are probably present only in a limited number of selected patients.

Altered erythrocyte Na-K pump in anorectic patients.

The status of the erythrocyte sodium pump was evaluated in a group of patients suffering from anorexia nervosa and a group of healthy female control subjects. Anorectic patients showed significantly higher mean values of digoxin-binding sites/cell (ie, the number of Na-K-ATPase units) with respect to control subjects while no differences were found in the specific 86Rb uptake (which reflects the Na-K-ATPase activity) between the two groups. A significant correlation was found between relative weight and the number of Na-K-ATPase pump units (r = -0.66; P less than 0.0001). Anorectic patients showed lower serum T3 concentrations (71.3 +/- 53 ng/dL) with respect to control subjects (100.8 +/- 4.7 ng/dL; P less than 0.0005) and a significant negative correlation between T3 levels and the number of pump units (r = -0.52; P less than 0.003) was found. Our study therefore shows that the erythrocyte Na-K pump may be altered in several anorectic patients. We suggest that this feature could be interrelated with the degree of underweight and/or malnutrition.

Determinants of sex hormone-binding globulin blood concentrations in premenopausal and postmenopausal women with different estrogen status. Virgilio-Menopause-Health Group.

In women, sex hormone-binding globulin (SHBG) concentrations are the result of a balanced effect of stimulatory and inhibitory factors. Estrogens represent the principal stimulatory hormones, whereas androgens, insulin, excess body fat, and the pattern of body fat distribution have inhibitory effects. Menopause is characterized by major changes in blood sex steroid concentrations, notably a marked reduction of estradiol levels. In this study, we therefore investigated the relationship between hormonal and nonhormonal regulatory factors of SHBG and its blood levels in two groups of premenopausal and postmenopausal women characterized by normal-high or reduced estrogen concentrations. The data were obtained from an analysis of the cross-sectional database obtained during the first survey of the Virgilio-Menopause-Health Project, an epidemiologic longitudinal study aimed at investigating the impact of menopause on body weight, fat distribution, and related major metabolic, hormonal, and cardiovascular risk factors. A total of 329 women, 133 in premenopause and 196 in postmenopause without diabetes, thyroid diseases, or relevant cardiovascular, renal, and hepatic dysfunction, were included in the study. A clinical history (including dietary and physical-activity habits), anthropometry (body mass index [BMI], waist to hip ratio [WHR], and bioelectrical impedance analysis [BIA]), and morning blood samples in the fasting state for sex hormones, insulin, and biochemistry were available for all the women. Premenopausal and postmenopausal women showed no significant difference in SHBG concentrations (38.7 +/- 17.9 v 36.6 +/- 17.5 nmol/L, respectively). On the contrary, postmenopausal women were characterized by a marked reduction of estradiol levels and significantly lower levels of testosterone. After adjusting for age, insulin was lower and the glucose to insulin ratio was higher in postmenopause than in premenopause. Age-adjusted values for all anthropometric parameters were not significantly different in the two groups. In simple correlation models, SHBG was significantly and negatively correlated with BMI, WHR, and insulin and testosterone levels in both premenopausal and postmenopausal women, whereas estradiol levels correlated positively and significantly with SHBG only in the premenopausal group. A significant positive correlation between the glucose to insulin ratio and SHBG was present in both groups. Using multiple regression models, in the premenopausal group, SHBG levels were correlated positively with estradiol and negatively with testosterone and insulin, but not with the WHR. On the contrary, in the postmenopausal group, SHBG values had a significant negative correlation with the WHR, whereas the relationship with estradiol was not significant; moreover, the relationship with testosterone and insulin, although significant, became less marked. In conclusion, this study indicates that (1) there is no significant difference in SHBG blood concentrations between premenopause and postmenopause; (2) SHBG values are correlated positively with estradiol and negatively with insulin and testosterone concentrations, but the predictive value of these variabiles on SHBG appears to be different in premenopause and postmenopause; and (3) SHBG levels decrease with increasing WHRs, particularly in the postmenopausal group. Therefore, determinants of SHBG blood concentrations are likely to change on passing from premenopausal to postmenopausal status. In particular, there seems to be a threshold level for which estradiol is an important determinant of SHBG blood concentrations.

Body fat distribution has weight-independent effects on clinical, hormonal, and metabolic features of women with polycystic ovary syndrome.

This study was performed to investigate whether different patterns of body fat distribution may have distinct effects on the clinical, hormonal, and metabolic features of women with clinical hyperandrogenism such as polycystic ovary syndrome (PCOS). Ninety-seven consecutive women with PCOS were included in the study after assessment of gynecological and obesity history and careful clinical examination. Women were divided into three tertile groups based on the waist to hip ratio (WHR). Those with peripheral body fat distribution (P-BFD) had a WHR of less than 0.80, those with intermediate body fat distribution (I-BFD) had a WHR of 0.81 to 0.90, and those with abdominal body fat distribution (A-BFD) had a WHR exceeding 0.90. Baseline blood and urine samples were obtained for several hormone and lipid determinations, and the response of glucose, insulin, and C-peptide to a glucose oral challenge (75 g) was investigated. In the PCOS group, WHR values were higher than those used to define P-BFD and A-BFD in the normal female population. As WHR values increased, a significantly greater prevalence of obesity and acanthosis nigricans and a lower prevalence of acne was present. No significant differences were present in any of the other clinical features between the three groups. Ovarian morphology and volumes were similar in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum leptin in obese women with polycystic ovary syndrome is correlated with body weight and fat distribution but not with androgen and insulin levels.

Leptin is a hormone produced in the adipose tissue and its concentrations in peripheral blood are significantly correlated with the amount of body fat. Whether other factors, including the pattern of body fat distribution and several hormones (such as insulin, sex steroids, and glucocorticoids), may be involved in the regulation of circulating blood leptin levels is controversial. Women with the polycystic ovary syndrome (PCOS) are hyperandrogenic and most of them are characterized by hyperinsulinemia, insulin resistance, and obesity, particularly the visceral phenotype. To assess the potential contribution of anthropometric factors, androgens, and insulin in determining leptin levels, we examined their relationship with body-mass index (BMI), visceral (VAT) and subcutaneous (SAT) adipose tissue areas, basal androgen levels, and fasting and glucose-stimulated (AUC) insulin in different groups of obese women with PCOS (n = 23) and of age-matched obese (n = 16) and non-obese (n = 10) otherwise healthy controls. The VAT/SAT ratio was measured as a parameter of body fat distribution. Serum leptin levels were significantly higher in obese PCOS women than in obese and normal-weight healthy controls and, within the controls, in the obese than in the non-obese group. In all women considered together, and in each group separately, leptin concentrations were highly significantly correlated with BMI. In addition, after adjusting for BMI, both VAT and the VAT/SAT ratio were positively and significantly correlated with leptin. Partial correlations with the VAT/SAT ratio remained significant in both the obese PCOS group and in controls considered separately, whereas the correlation with the SAT value was significant only in the control group. After adjusting for BMI, no correlation between leptin, androgens and fasting or stimulated (like AUC) insulin was found. These findings indicate that leptin levels in obese women with PCOS are higher than those observed in obese and non-obese controls. Moreover, they suggest that, other than BMI, the pattern of body fat distribution may be an independent factor related to circulating leptin levels, which, on the contrary, do not appear to be related to either androgen or insulin concentrations.

The role of the opioid peptides in the development of hyperinsulinemia in obese women with abdominal body fat distribution.

In this study, we investigated the hypothesis that increased opioid activity may be involved in the development of hyperinsulinemia in women with obesity and abdominal body fat distribution. Two groups of nine obese body (body mass index [BMI], 30 to 40 kg/m2) women with abdominal (A-ob) (waist to hip ratio [WHR] greater than 0.85) or gluteo-femoral (F-ob) (WHR greater than or equal to 0.80) fat distribution were examined and compared with eight normal-weight controls. Basal beta-endorphin levels were higher in the A-ob group than in the other groups. Each woman underwent two oral glucose tolerance tests (OGTT, 75 g glucose). A bolus of naloxone (0.8 mg) followed by a constant infusion of naloxone (0.04 mg/kg/h) or saline was also administered during the glucose challenge in random order, and blood samples for glucose, insulin, and C-peptide were collected at regular times after glucose administration. No difference was observed in basal or stimulated glucose concentrations between the three groups, nor between the saline or naloxone study. However, basal and stimulated insulin levels were significantly higher in obese women (particularly in the A-ob group) than in controls. Naloxone administration, however, did not significantly modify insulin and C-peptide glucose-stimulated concentrations in controls and in the F-ob group, whereas it significantly reduced (by approximately 47%) insulin levels in the A-ob group. Partial correlation coefficients showed a significant negative correlation between percent variation of glucose-stimulated insulin incremental areas during the naloxone study and the WHR in all women considered together (r = .544, P less than .025).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of acute hyperinsulinemia on testosterone serum concentrations in adult obese and normal-weight men.

In a previous study performed in adult obese and normal-weight male subjects, we found that suppression of insulin levels by diazoxide reduced testosterone and increased sex hormone-binding globulin (SHBG) blood concentrations. These and other data suggested that insulin may have a regulatory capacity in testosterone secretion and/or metabolism in men, similar to what has already been demonstrated in women. In this study, we investigated the effects of acute hyperinsulinemia on major androgen levels, including testosterone, in two groups of normal-weight in = 11) and obese (n = 9) men. Acute hyperinsulinemia was obtained by the euglycemic-hyperinsulinemic clamp technique. Relationships between the degree of insulin resistance (ie, total glucose disposal [M value]) and testosterone levels were also evaluated. Basal testosterone levels in obese subjects (10.40 +/- 3.02 nmol/L) were significantly lower than in normal-weight controls (15.50 +/- 4.65 nmol/L, P < .01), whereas no difference was present in androstenedione and dehydroepiandrosterone sulfate (DHEA-S) concentrations. During the clamp study, testosterone was significantly increased in the obese group (11.79 +/- 3.64 nmol/L, P < .05) but not in the control group (15.81 +/- 4.54 nmol/L, P = NS). The other two androgens did not significantly change in either the obese or control group. There was a highly significant correlation between baseline testosterone concentrations, with M values suggesting a relationship between impaired peripheral insulin sensitivity and reduced plasma testosterone concentrations. It should be pointed out that there was a certain discrepancy in the testosterone variations, particularly in the control group, in which two thirds of the subjects had no change or some decrease in testosterone levels, whereas in the remainder testosterone increased over the values of the assay variation coefficient. These findings are consistent with the hypothesis that insulin may regulate testosterone blood levels also in male subjects. Whether these effects are primarily due to increased hormone secretion or reduced clearance needs to be investigated.

Effect of obesity and body fat distribution on sex hormones and insulin in men.

To investigate the relationship between body fat distribution, sex hormones, and hyperinsulinemia in male obesity, we examined 52 obese men (body mass index [BMI], 35.0 +/- 6.1, mean +/- SD) and 20 normal-weight controls. Their waist to hip circumference ratio (WHR), which was used as an index of fat distribution, was 0.985 +/- 0.052 and 0.913 +/- 0.061 (P less than .005), respectively. Compared with controls, obese men presented significantly lower levels of total (357 +/- 132 v 498 +/- 142 ng/dL; P less than .005) and free testosterone (14.2 +/- 2.9 v 17.1 +/- 2.6 pg/mL; P less than .05) and sex hormone-binding globulin (SHBG; 41.7 +/- 31.9 v 66.2 +/- 18.6 nmol/L; P less than .001) without any significant difference on the other sex steroid or on gonadotropin concentrations. Fasting and glucose-stimulated insulin and C-peptide levels were significantly higher in obese than in controls, and in obese with the WHR value greater than 0.97 (corresponding to the distribution median) than in those with WHR lower or equal to 0.97. BMI was negatively correlated with testosterone (P less than .005), free testosterone (P less than .01), and SHBG (P less than .001) and positively with fasting (P less than .001) and glucose-stimulated (P less than .005) C-peptide concentrations, whereas no relationship was found between these variables and WHR values. On the contrary, WHR was significantly correlated with fasting and post-glucose insulin levels (P less than .05), but not with those of sex steroids.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypothalamic-pituitary-adrenal axis activity and its relationship to the autonomic nervous system in women with visceral and subcutaneous obesity: effects of the corticotropin-releasing factor/arginine-vasopressin test and of stress.

In a previous study, we demonstrated that premenopausal women with visceral obesity have hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, characterized by an exaggerated hormone response to corticotropin-releasing factor (CRF) and corticotropin (ACTH) stimulation. The hypothalamic peptide flow that stimulates the pituitary, particularly after a physiological stress challenge, involves not only CRF, but also arginine-vasopressin (AVP), which synergizes the CRF capacity to stimulate pituitary hormone secretion. Previous studies in humans have demonstrated that combining AVP with CRF permits maximal stimulation of the pituitary, providing a more appropriate method of assessing pituitary hormone reserve. We therefore investigated the response of the HPA axis to combined CRF and AVP stimuli in obese women with different obesity phenotypes. Moreover, we examined hormonal and cardiovascular responses to several mental stress tasks, according to previously standardized procedures. Two groups of age-matched premenopausal eumenorrheic obese women with visceral (V-BFD) or subcutaneous (S-BFD) body fat distribution and a group of normal-weight healthy controls were investigated. All women randomly underwent the following protocol: (1) a combined CRF/AVP test (100 micrograms plus 0.3 IU intravenously [IV], respectively); (2) a standardized stress test, which consisted of completing two puzzles and a mental arithmetic test; and (3) a control saline test. Blood samples for ACTH and cortisol determinations were obtained before and during each test, and measurements of arterial blood pressure and pulse rate were made at regular intervals during the stress test. After combined CRF/AVP administration, ACTH and cortisol were significantly higher in V-BFD than in the other two groups. In contrast, no significant hormonal variation was found in either group during stress tasks. During the stress test, pulse rate (but not arterial blood pressure) significantly increased after 8 and 15 minutes in the V-BFD group, whereas no significant variation was found in S-BFD and control women. A significant correlation was present between the pulse rate and change in cortisol level during the stress test at minutes 8 (r=.54, P<.05) and 15 (r=.57, p<.01) in all women considered together. Subjective emotional involvement during stressful tasks was measured by a two-dimensional short verbal scale, which revealed that the stress section had a more significant impact in obese V-BFD than in S-BFD and control women. These data therefore confirm that women with visceral obesity have hyperactivity of the HPA axis, and that the combined CRF/AVP stimulation may offer a good tool for investigating pituitary reserve in this obesity phenotype. Moreover, the results indicate that these women probably have a hyperreactive sympathetic response to acute stress that seems interrelated to that of the HPA axis.

[Obesity and adipose tissue distribution in men: relation to sex steroids and insulin]. / Obesità e distribuzione del tessuto adiposo nell'uomo: relazione con gli steroidi sessuali e l'insulina.

The aim of this study was to assess the correlation between the distribution of adipose tissue, sexual hormones and hyperinsulinemia in male obesity. Fifty-two obese males, aged 40.0 +/- 10.9 years old and with a body mass index (BMI) of 35.0 +/- 6.1 (m +/- SD), not suffering from diabetes or any other endocrine disease, were included in the study. A group of 20 subjects aged 30.5 +/- 7.9 (p less than 0.005 vs obese subjects) and with a BMI of 23.0 +/- 2.0 were used as controls. Body fat distribution was assessed using the waist/hip ratio (w/h ratio): 0.985 +/- 0.052 in obese subjects and 0.913 +/- 0.061 in controls (p less than 0.005). In comparison to control subjects, significantly lower levels of total (T) (357 +/- 132 vs 498 +/- 142 ng/dl; p less than 0.005) and free testosterone (FT) (14.2 +/- 2.9 vs 17.1 +/- 2.6 pg/ml; p less than 0.05) were found in the obese group, as well sex hormone binding globulin (SHBG) (41.7 +/- 31.9 vs 66.2 +/- 18.6 nmol/l; p less than 0.001). None of the other steroids (androstenedione, dehydroepiandrosterone-sulphate, estrone, 17 beta-estradiol, dihydrotestosterone) or FSH and LH gonadotropins assayed differed between the two groups. Significantly higher levels of insulin and C-peptide, both fasting and after a oral glucose tolerance test, were also found in obese subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of guar on plasma lipids and on the biological activity of insulin in patients with type 2 diabetes mellitus]. / Effetto del guar sui lipidi plasmatici e sulla attività biologica dell'insulina nei pazienti con diabete tipo 2.

10 patients with type 2 diabetes mellitus, in stable weight and diet therapy, followed a 2 months nutritional supplementation with guar, 15 g/day. Their previous nutritional and pharmacological therapy was not modified throughout the study. No changes occurred in body weight or major parameters of metabolic control. However, a significant fall occurred in fasting plasma, total and LDL cholesterol, and apolipoprotein B concentrations. Insulin sensitivity, measured by the "steady state plasma glucose", obtained after a 150 min glucose-insulin-somatostatin infusion, improved in all patients but two. A significant correlation was observed between steady state plasma glucose variations, the glycosylated haemoglobin A1c (r = 0.70; p less than 0.005), total (r = 0.77; p less than 0.001), and LDL cholesterol (r = 0.69; p less than 0.005) and apolipoprotein B concentrations (r = 0.75; p less than 0.005).

Weight control and its beneficial effect on fertility in women with obesity and polycystic ovary syndrome.

Obesity may be an important pathogenetic factor involved in the development of hyper-androgenism in women with polycystic ovary syndrome (PCOS). Among several other mechanisms, hyperinsulinaemia plays a fundamental role, due to its gonadotrophic function, which has been demonstrated both in vitro and in vivo. Therefore, not surprisingly, weight loss may be expected to have several beneficial effects upon clinical, endocrinological and metabolic features of obese women presenting both PCOS. In particular, weight loss appears to be associated with a significant improvement in menses abnormalities, ovulation and fertility rates, and with a reduction of hyperandrogenism, hyperinsulinaemia, and altered gonadotrophin pulsatile secretion. The central role of improved insulin concentrations and insulin-resistant state is emphasized by the fact that similar effects can be achieved by both short- and long-term administration of metformin, an insulin-lowering drug which ameliorates peripheral insulin action in non-diabetic insulin resistant states. We therefore recommend weight loss as a first-line therapeutic option in all women with obesity and PCOS.

Characterization of obese women with reduced sex hormone-binding globulin concentrations.

Factors influencing sex-hormone binding globulin (SHBG) concentrations in obesity are poorly understood. Preliminary observations suggest that dietary lipids may be involved and there are data confirming a direct inhibiting effect of insulin. Since only some obese subjects show lowered SHBG levels, we performed this study with the aim of defining obese women with low SHBG (LSO) (2 SD above normal values) in comparison with those presenting normal globulin concentrations (NSO). These groups were selected from a larger group of obese women with a history of normal menses and aged less than 40 years. An age-matched group of normal weight healthy women served as controls. Both LSO and NSO had similar body mass index and percentage body fat, but the waist to hip girth ratio (WHR), an index of body fat distribution, was significantly higher in LSO (0.88 +/- 0.04) than in NSO (0.81 +/- 0.09; P less than 0.05). Gonadotropin and androgen concentrations were similar in both groups, whereas estrone (E1) levels were higher in LSO (32.8 +/- 15.8 pg/ml) than in NSO (19.4 +/- 6.2 pg/ml; P less than 0.05; controls: 23.5 +/- 7.8 pg/ml; P less than 0.05). Moreover, compared to NSO, LSO women had significantly higher glucose-stimulated insulin and C-peptide levels. Partial regression analysis revealed significant correlation coefficients between SHBG, stimulated insulin values (r = -0.38; P less than 0.05) and WHR (r = 0.40; P less than 0.005). Therefore, compared to NSO, LSO women have distinctive clinical and endocrine characteristics, namely more pronounced hyperinsulinemia, higher E1 concentrations and a central type body fat distribution.

Erythrocyte Na+-ATPase in obese patients.

Na+-K+-ATPase activity, as measured by erythrocytic 86Rb uptake and number Digoxin Binding Sites were evaluated in 34 obese patients and in 39 control subjects. No differences were found in 86Rb uptake and Digoxin Binding Sites between obese and controls. Likewise no differences were found between obese patients on their spontaneous caloric intake and those studied during various hypocaloric regimens. Finally, no relationship between thyroid hormone serum concentrations and ATPase activity was found in the group of obese patients.