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Query: UMLS:C0028754 (obesity)
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In recent years numerous studies have suggested insulin to be an important regulator of ovarian function and hyperinsulinemia to be associated with hyperandrogenism. An oral glucose-tolerance test was carried out in 240 women with polycystic ovary syndrome and, based on its result, 142 of the women (59.2%) were insulin resistant or hyperinsulinemic and 98 (40.8%) were normoinsulinemic. Compared with the normoinsulinemic group, the hyperinsulinemic group had a greater incidence of obesity (52.8 vs. 21.4%), secondary amenorrhea (24.6 vs. 9.2%), androgenic symptoms (85.9 vs. 67.4%) and, in particular, hirsutism with or without acne (71.8 vs. 48.0%). Moreover, the hyperinsulinemic group had significantly higher plasma levels of androstenedione, testosterone, free testosterone and insulin, and lower levels of luteinizing hormone, estradiol and sex hormone-binding globulin.
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PMID:Hyperinsulinemia in the polycystic ovary syndrome: a clinical, endocrine and echographic study in 240 patients. 891 61

The objective was to study the pathophysiology of the dyslipidaemia in polycystic ovarian syndrome (PCOS) patients, and to determine how it is related to hyperinsulinaemia, hyperandrogenism and dehydroepiandrosterone sulphate (DHEA-S) concentrations. The lipoprotein lipid profile, anthropometric measurements, endocrine profile and the presence of insulin resistance were evaluated in 31 PCOS patients and 20 age-matched healthy women, who served as controls. PCOS patients had higher fasting insulin concentrations, higher body mass indexes (BMI) and were hyperlipidaemic, with higher total cholesterol, low density lipoprotein (LDL) and triglyceride (TG) concentrations. There were no relationships between plasma lipids and anthropometric variables in the patient group as a whole. Insulin-resistant (IR) and non-IR (NIR) PCOS patients were then evaluated separately. Obesity with marked hyperandrogenism were the predominant features in patients with IR. NIR patients were not obese and had significantly less hyperandrogenism. The adrenal androgen DHEA-S was at the upper limit of its normal range in both groups. However, both PCOS subgroups exhibited similar significant abnormalities in terms of their lipid parameters. Insulin and DHEA-S concentrations were positively correlated with total cholesterol, LDL and TG, and negatively correlated with high density lipoprotein, in IR patients. In NIR subjects, insulin was not correlated with any of the lipids and DHEA-S was negatively related to cholesterol and LDL. Anthropometric variables were related to lipids in only the NIR patients. Thus PCOS subjects as a group exhibit dyslipidaemia, characterized by increased total cholesterol, LDL and TG concentrations. When divided into IR and NIR subjects, there were no differences in the degree of lipid abnormalities, despite significant variations in the BMI and androgen status. Thus, in PCOS subjects, dyslipidaemia may occur irrespective of insulin resistance. Insulin and DHEA-S concentrations were positively correlated with an atherogenic lipid profile in the IR group only. As distinct from syndrome X when IR was present, dyslipidaemia was not related to body weight or the waist:hip ratio. In the NIR group there was no relationship between lipids and insulin; DHEA-S, on the other hand, was negatively related to cholesterol and LDL concentrations. Thus, dyslipidaemia in PCOS patients may occur irrespective of insulin resistance, and may have different metabolic aetiologies depending on DHEA-S metabolism. It remains to be seen whether the two types of PCOS are associated with different risks for ischaemic heart disease.
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PMID:Dyslipidaemia in polycystic ovarian syndrome: different groups, different aetiologies? 892 Oct 52

Breast cancer incidence rates are high in societies with a Western lifestyle characterized by low levels of physical activity, and by an energy-dense diet rich in total and saturated fat and refined carbohydrates. Epidemiologic studies, so far mostly on postmenopausal women, have shown that breast cancer risk is increased in hyperandrogenic women, with decreased levels of plasma sex-hormone binding globulin, and with increased levels of testosterone and of free estrogens. This paper describes the role of hyperinsulinemia as a physiologic link between nutritional lifestyle factors, obesity, and the development of a hyperandrogenic endocrine profile, and reviews evidence that may or may not support the theory that chronic hyperinsulinemia is an underlying cause of breast cancer. An hypothesis is presented, stipulating that breast cancer risk is increased not only in hyperandrogenic postmenopausal women, but also in premenopausal women with mild hyperandrogenism and normal (ovulatory) menstrual cycles. The author suggests further investigation as to whether there is a positive association between risk of breast cancer before menopause and subclinical forms of the polycystic ovary syndrome (PCOS), and to what extent diet and physical activity during childhood, by modulating the degree of insulin resistance during adolescence, may or may not be determinants of a PCO-like hyperandrogenic endocrine profile persisting into adulthood.
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PMID:Nutrition, hormones, and breast cancer: is insulin the missing link? 893 15

A relationship exists between obesity and non-insulin-dependent diabetes mellitus. Central, abdominal obesity carries a particularly high risk that is most likely associated with enlargement of visceral fat deposits. A multiple endocrine perturbation is associated with visceral obesity. This consists of a hypersensitive hypothalamic-pituitary-adrenal (HPA) axis, with resulting excess of cortisol secretion upon stimulation. Growth hormone levels in both sexes are diminished and testosterone concentrations in men are lower than normal. In women a moderate hyperandrogenism is often present. The elevated sensitivity of the HPA axis may be a primary event, followed by adrenal androgen production in women and by interaction at several levels, with inhibition of both the growth hormone and pituitary-gonadal axes. Together, these endocrine perturbations seem to be able to centralize body fat to visceral depots because of a high density of steroid hormone receptors. The endocrine perturbations are most likely followed by insulin resistance. Elevated cortisol levels, deficiencies in sex-specific steroid hormones and excess androgens result in insulin resistance. The endocrine abnormalities in visceral obesity are followed by insulin resistance, both directly and indirectly via contribution of excess free fatty acids from centralized body fat depots. The hyperactivity of the HPA axis may be due to frequent challenges and it is amplified by a deficient feedback inhibition. A depressive, helplessness reaction to stress may be involved. Such stress factors may be found in socioeconomic and psychosocial handicaps, as suggested by results of population studies. This hypothesis is strongly supported by the reproduction of an identical condition in non-human primates that react with a depressive reaction upon psychosocial types of stressors. The perturbations of the HPA axis may thus be in the centre of the syndrome. Studies of this axis in established non-insulin-dependent diabetes mellitus suggest similar perturbations, but the information is not conclusive.
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PMID:The origins and consequences of obesity. Diabetes. 901 75

Observations on body weight, circulating androstenedione concentrations and morphology of ovarian stroma were made in Scotophilus heathi during the period of delayed ovulation to make a comparison with polycystic ovarian syndrome in women. Body weight of bats increased from a level of 31.00 +/- 0.30 g in August and reached a peak of 45.00 +/- 0.46 g in November. This increase in body weight was due to accumulation of adipose tissue. The body weight declined gradually from December onwards and finally reached a basal level in March. The circulating androstenedione concentration showed a gradual increase from 36.80 +/- 15.54 ng/ml in August and reached a peak level of 220.50 +/- 50.10 ng/ml in November. Androstenedione concentration reached the lowest level in the March, just before ovulation. Morphological study showed extensive distribution of luteinized stromal cells or interstitial cells (ICs). Morphometric study showed that during the period of ovulatory delay, more than 75% area of the ovary was occupied by the ICs. Hyperandrogenism, anovulation, obesity (fat deposition) and stromal hyperthecosis present during delayed ovulation in S. heathi may serve as an experimental model for some aspects of the polycystic ovarian condition in women.
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PMID:Adiposity and androstenedione production in relation to delayed ovulation in the Indian bat, Scotophilus heathi. 908 Jun 76

The growth hormone (GH) response to stimulation tests is impaired in obesity. Moreover, obese patients exhibit a "paradoxical" increase of GH to GH-releasing hormone (GHRH) stimulation after food ingestion; this paradoxical response is reversed by naloxone infusion. On the other hand, beta-endorphin seems to exert profound effects on insulin release. Recent studies also demonstrated an impairment of GH response to several stimuli in polycystic ovary syndrome (PCOS), a condition associated with obesity, hyperinsulinism, and insulin resistance. Chronic inhibition of opioid tone by the opioid antagonist naltrexone (NTX) is able to reduce the insulin response to an oral glucose tolerance test (OGTT) in hyperinsulinemic PCOS patients. Since insulin and GH may reciprocally influence their secretion and the opioid system may have a role in the pathogenesis of hyperinsulinemia and reduced GH secretion, we have explored the involvement of these neuroendocrine mechanisms in essential obesity and in obesity associated with hyperandrogenism by a long-term treatment with an opiate antagonist. We tested seven obese patients affected by PCOS, seven matched women with essential obesity (EO), and five non-obese control subjects. All patients, in the follicular phase, underwent an OGTT (75 g) and basal hormone assay. Two days later, patients were subjected to a GHRH test. The patients then had 4 weeks of treatment with NTX 50 mg/d. Following continuation of the treatment, OGTT and GHRH tests were repeated. Insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) plasma concentrations were also determined in the basal condition before and after NTX treatment. NTX treatment reduced fasting insulin levels in patients with EO (P < .05) and restored a normal GH response to GHRH without affecting IGF-1 and IGFBP-3 levels. In PCOS subjects, NTX reduced the insulin response to a glucose load and failed to modify the blunted GH response to GHRH. Our data suggest a significant difference in opioid system function in PCOS and EO subjects, indicating a particular form of obesity in PCOS. The opiate antagonist treatment in EO may act through the reduction of negative insulin feedback on GH secretion. In PCOS patients, the failure to improve GH secretion in obese hyperandrogenized patients may be related to a high opioidergic tone or to the inhibitory predominance of other neurotransmitters.
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PMID:Impact of long-term naltrexone treatment on growth hormone and insulin secretion in hyperandrogenic and normal obese patients. 916 Aug 21

Hypertension is often accompanied by a host of metabolic defects. Investigations have shown an association between insulin resistance, hyperinsulinemia, central/visceral obesity, and hypertension. Recent interest has focused on the fact that untreated hypertensive individuals have compensatory hyperinsulinemia, are resistant to insulin-mediated glucose uptake, and frequently have coexisting lipid abnormalities. Data from prospective studies appear to indicate that fasting hyperinsulinemia is an independent predictor of coronary artery disease. Additionally, there is evidence that hyperinsulinemia and diabetes eliminate the normal sex differences in the prevalence of coronary artery disease. The salutary effects of ovarian hormones on the prevalence of hypertension and cardiovascular disease in postmenopausal women are well established. Hyperandrogenism, in particular elevated serum levels of dehydroepiandrosterone sulfate, is believed to be a risk factor promoting sex-specific impairments of glucose and lipid metabolism, obesity, and hypertension in women. Clinical and epidemiologic evidence have linked elevated blood pressure to disturbances in lipoprotein metabolism, fibrinolytic activity, plasminogen activation inhibitor levels, and dyslipidemia. This review briefly presents the current understanding of various metabolic disturbances associated with hypertension, the pathophysiologic mechanisms involved, and the significance of the interplay between them relative to the complications of this disease.
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PMID:Metabolic abnormalities in hypertension. 926 63

Polycystic ovary syndrome (PCOS) is a heterogeneous clinical entity that is defined as the association of hyperandrogenism with chronic anovulation in women without specific underlying diseases of the adrenal or pituitary glands. PCOS is also associated with a metabolic disturbance (insulin resistance). The nature of the complex interrelation of obesity, insulin resistance and endocrine abnormalities in PCOS remains unresolved. However, several studies link obesity, body fat distribution and nutritional habitus with the hormonal and metabolic profiles of PCOS. Moreover, intervention studies have suggested that reducing weight and/or hyperinsulinaemia either by diet alone or by a combination of diet and drugs improves hirsutism, fertility and the hormonal and metabolic profiles of PCOS. In fact, the evaluation of nutritional factors in PCOS is helpful for the screening of metabolic abnormalities and the management of women with PCOS. A point of particular interest in the management of PCOS is that the choice of contraception remains difficult in these high cardiovascular risk women. The impact of pills with ethinyl oestradiol on weight, body fat distribution and carbohydrate metabolism in women with PCOS has not been thoroughly evaluated. The lack of prospective studies to evaluate long-term metabolic and cardiovascular tolerance necessitates care and the assessment of other hormonal possibilities.
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PMID:Influences of weight, body fat patterning and nutrition on the management of PCOS. 940 23

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.
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PMID:Weight control and its beneficial effect on fertility in women with obesity and polycystic ovary syndrome. 940 24

It is now clear that PCOS is often associated with profound insulin resistance as well as with defects in insulin secretion. These abnormalities, together with obesity, explain the substantially increased prevalence of glucose intolerance in PCOS. Moreover, since PCOS is an extremely common disorder, PCOS-related insulin resistance is an important cause of NIDDM in women (Table 3). The insulin resistance in at least 50% of PCOS women appears to be related to excessive serine phosphorylation of the insulin receptor. A factor extrinsic to the insulin receptor, presumably a serine/threonine kinase, causes this abnormality and is an example of an important new mechanism for human insulin resistance related to factors controlling insulin receptor signaling. Serine phosphorylation appears to modulate the activity of the key regulatory enzyme of androgen biosynthesis, P450c17. It is thus possible that a single defect produces both the insulin resistance and the hyperandrogenism in some PCOS women (Fig. 19). Recent studies strongly suggest that insulin is acting through its own receptor (rather than the IGF-I receptor) in PCOS to augment not only ovarian and adrenal steroidogenesis but also pituitary LH release. Indeed, the defect in insulin action appears to be selective, affecting glucose metabolism but not cell growth. Since PCOS usually has a menarchal age of onset, this makes it a particularly appropriate disorder in which to examine the ontogeny of defects in carbohydrate metabolism and for ascertaining large three-generation kindreds for positional cloning studies to identify NIDDM genes. Although the presence of lipid abnormalities, dysfibrinolysis, and insulin resistance would be predicted to place PCOS women at high risk for cardiovascular disease, appropriate prospective studies are necessary to directly assess this.
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PMID:Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis. 940 43


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