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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A physiological in vivo increase of plasma free fatty acid concentration after an overnight fast was found to be accompanied by a rise of the non-protein bound estradiol fraction. A similar increase was observed after lipase activation by the i.v. injection of 500 IU heparin in 5 healthy non-fasting subjects. In vitro studies showed a direct relationship between non-protein bound estradiol and the concentration of linoleate, linolenate, and arachidonate both in undiluted serum and in Ringer's solution containing human serum albumin (45 g/liter). Moreover, the estradiol sex hormone binding globulin complex bound to a solid concanavalin A-Sepharose matrix was markedly dissociated by oleate and even more by linoleate, linolenate, or arachidonate. These results suggest that physiological diurnal elevations in plasma free fatty acids which are amplified by high fat consumption, obesity, and stress may imply major proportional increases of available estradiol, exerting a promotional effect on breast and endometrial cancer over the years.
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PMID:Free fatty acid concentrations correlated with the available fraction of estradiol in human plasma. 369

Comparisons are made of the plasma binding capacity and concentration of sex hormone binding globulin. Concentration was measured by electroimmunodiffusion standardised in terms of mass of the protein and binding capacity by two methods measuring the binding of 5 alpha-dihydrotestosterone. Isolation of steroid bound by SHBG was by either ammonium sulphate precipitation or cellulose filter discs. Both binding methods correlate highly with electroimmunodiffusion indicating they respond similarly to changes in the plasma concentration of the protein. However, they do not equally reflect the actual concentration. Estimates of the molecular mass of the protein of 188000 and 100000 from the precipitation and disc methods respectively, suggest the former measures less of the protein present than does the latter. A parallel reduction in binding capacity and concentration is seen in obese post-menopausal females. This previously unreported finding suggests that the reduced plasma binding capacity of sex hormone binding globulin in obesity is not due to altered or impaired steroid binding.
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PMID:Comparative measurements of plasma binding capacity and concentration of human sex hormone binding globulin. 642 22

Twenty-three women considered to have polycystic ovarian disease (PCO) were studied in an effort to better understand the mechanism of inappropriate secretion (IGS) which is so characteristic of these women. Criteria for PCO included oligomenorrhea, infertility, an obesity index (ponderal index, PI) < 12, and an LH:FSH ratio > 3. The mean +/- SE weight and PI for this group were 175 +/- 7.5 lbs. and 11.2 +/- 0.2 respectively. Weight was not correlated with steroid levels in PCO or control women. The mean (+/- SE) of serum androgen concentrations (DHEA-S: 2.9 +/- 0.5 micrograms/ml; androstenedione: 2.6 +/- 0.3 ng/ml; and testosterone: 47 +/- 5 ng%) were all significantly higher than those in control women (p < .05). Total serum estradiol (E2) was comparable to those of controls in the follicular phase, while estrone (E1): E2 ratios averaged 2:1. Serum sex hormone binding globulin-binding capacity (SHBG-BC) averaged 56.8 +/- 4.2 nM which was significantly lower than that of controls (p < .05). The percent unbound E2 was significantly elevated in PCO (62% vs 37%). The mass of unbound E2 was also significantly higher in PCO women (40 +/- 3 pg/ml) than in controls (17 +/- 2 pg/ml) (p < .005). Serum LH:FSH ratios had a positive correlation with the relative and absolute concentration of unbound E2. In control women, unbound E2 correlated significantly with LH levels. This suggests that IGS characteristically found in PCO patients and exemplified by elevated LH;FSH ratios, is the result of the feedback response to elevated levels of unbound (i.e., biologically active) E2.
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PMID:Elevations in unbound serum estradiol as a possible mechanism for inappropriate gonadotropin secretion in women with PCO. 677 90

At menopause, several abnormalities in oestrogen metabolism have been reported, which may increase the likelihood of cancer development in the breast or uterus following oestrone or oestradiol-17 beta supplementation. Occult hypothyroidism reduces the rate of oestrogen inactivation by C2 hydroxylation, and 15-20% of women have low rates of C16 hydroxylation to oestriol. Reduced sex hormone binding globulin concentration occurs in association with obesity, thereby increasing the biologically active unbound fraction of oestradiol in plasma. Since oestriol undergoes minimal metabolism after absorption, does not bind to sex hormone binding globulin, and has an anti-oestradiol action by decreasing the duration of nuclear binding of oestradiol-receptor proteins, it is less likely to induce proliferative changes in target organs of cancer-prone women than oestrone or oestradiol. Intermittent non-conjugated oestriol treatment has demonstrated the most significant anti-mammary carcinogenic activity of 22 tested compounds as well as anti-uterotropic activity in intact female Sprague Dawley rats fed either of two dissimilar carcinogens (7, 12 dimethylbenz(a) anthracene, procarbazine) and followed for their natural life span. The protective effect was specific for mammary carcinomas only and has been decreased in rats with a 20% increase in growth curves. Clinical experience thus far with oral oestriol therapy of post-menopausal women has indicated little hazard of cancer development.
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PMID:Pathophysiologic considerations in the treatment of menopausal patients with oestrogens; the role of oestriol in the prevention of mammary carcinoma. 699 3

A prospective study was carried out on 158 anovulatory women for the purpose of finding parameters that might predict the clomiphene dose at which ovulation would occur. Both body weight and obesity were positively correlated with the dose required to achieve ovulation (P less than 0.05). Once ovulation occurred, obesity did not affect the ability to conceive. Fifty-eight women who ovulated with various doses of clomiphene, including six women who failed to ovulate, had hormonal measurements performed prior to treatment. Compared with normally ovulating controls, serum luteinizing hormone (LH), the ratio of LH to follicle-stimulating hormone (FSH), serum androgens, unbound testosterone, and unbound estradiol were elevated and sex hormone binding globulin-binding capacity (SHBG-BC) significantly lower in women receiving clomiphene. Although the ovulatory dose of clomiphene was positively correlated with both weight and obesity, neither weight nor any laboratory parameter could accurately predict the clomiphene response.
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PMID:Clinical and laboratory predictors of clomiphene response. 719 84

Levels of serum androgens and sex hormone binding globulin (SHBG) were measured in 20 obese Pima Indian females aged 19-44 and compared with those of normal-weight Caucasians aged 20-46. The Pima exhibited significantly decreased SHBG compared to Caucasians, but a strong effect of age on androgen levels rendered mean comparisons useless. Androstenedione (A) and dehydroepiandrosterone-sulfate (DHEA-S) decreased significantly, and testosterone (T) declined slightly with age in the Pima, whereas these androgens showed no significant decreases in Caucasians for this age range. A possible relationship of androgens to the Pima female's propensity for android obesity as well as possible effects of obesity on SHBG, and aging is discussed.
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PMID:Serum Androgens and sex hormone binding globulin in obese Pima indian females. 719 23

Type IIB muscle fibres are among the most insulin-insensitive muscle fibres and are not adapted to oxidation of fat during muscle work. The first characteristic of this type of muscle fibre most probably reflects or contributes to further development of insulin resistance contribute to further perpetuation of obesity and to the channeling of excess free fatty acids to the liver followed by secondary deterioration of its function. The impaired functioning of the liver is epitomized, among other changes, by impairment of insulin extraction. The increasing hyperinsulinaemia is followed by inhibition of synthesis of specific proteins such as carrier proteins for transporting testosterone (sex hormone binding globulin, SHBG). This results in an increased free testosterone concentration which induces androgenization in women and may further increase insulin insensitivity in abdominal obesity in women. The poor capillarization and changed muscle morphology in spite of great interindividual variety is observed in several pathological conditions characterised by insulin sensitivity (stroke, PCO, hypertension, diabetes, obesity). It is suggested that, in addition to the previous concept of the main role of intraabdominal adipose tissue, even muscles and liver are also important organs contributing to the pathogenesis and development of the metabolic syndrome.
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PMID:Role of muscle morphology in the development of insulin resistance and metabolic syndrome. 783 Dec 32

Interrelationship between the body mass index (BMI), the waist-hip ratio (WHR) and serum concentration of immunoreactive insulin (IRI), C-peptide and sex hormone binding globulin (SHBG) was investigated in adolescents with obesity. Significant positive correlations were found between BMI and IRI, between BMI and C-peptide and there was a negative correlation between BMI and SHBG. WHR did not correlate with IRI, C-peptide and SHBG. IRI, C-peptide and SHBG in the group of central and gluteal obesity differentiated by WHR did not differ significantly. These results suggest that use of WHR to differentiate central and gluteal obesity does not help in adolescent period, possibly because of somatic changes of puberty.
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PMID:[Value of the waist-hip ratio in adolescent obesity]. 805

Obesity is a product of welfare. About 1/3 of our population has got excessive weight, 6 to 8% is truly obese and in 0.1% we may speak of pathologic obesity. Obesity is not only an esthetic problem, but is goes together with higher morbidity and mortality. In men with a body mass index (BMI = W (kg)/L2 (m)) of more than 35, the glucose metabolism was disturbed in 70%, the lipid spectrum had a clearly atherogenic profile, the average (free) testosterone level was significantly diminished and there was also a certain degree of hypogonadism. A short term treatment (4 to 6 weeks) based on a hypocaloric diet (400) and rich in proteins normalized the glucose metabolism in a very great number of patients, while the insulinemia fell with 40% and the lipidogram always became normal, but for the HDL-C, which showed a slight drop, while the testosterone levels became normal with a strong rise of the sex hormone binding globulin. And yet, at that very moment the patients were still definitely obese: this suggests that the metabolic disturbances are not the consequence of obesity in itself, but may be related to the dietary habits of the patients. Concerning the mechanism of hypogonadism, the cause of its disturbance seems to be situated in the hypothalamo-hypophyseal area and be characterized by a lower amplitude of LH-pulses, which are correlated with the testosterone levels. This hypothalamic disorder is however not limited to the LH-secretion, but the amplitude of growth hormone- and of ACTH-pulses is also reduced. Our study suggests that not obesity itself, but dietary factors might be responsible for the detected abnormalities. This might have important implications. Indeed, it is well known that in population groups, whose diet contains fewer calories and less fat--such as the Chinese and the Japanese--sex hormone binding globulin exists in far higher concentrations whereas free testosterone is found in a lower concentration. In these populations the prevalence of clinically obvious prostate cancer--which is androgen-sensitive--is much lower than in Western countries: it seems obvious to look for a correlation between both observations. Another remarkable phenomenon is the difference in testosterone metabolism between the Eastern and Western people; this leads us to the remarkable findings that in Asian people the same amount of androgens nearly always produces azoospermia and infertility, whereas this appears in only 2/3 of the cases among Western people.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Metabolic effects of obesity in men]. 812 79

The prevalence of obesity is increasing in the developed as well as underdeveloped countries. Obesity in women is associated with reproductive disorders. The levels of estrone and androgens are higher in obese women along with a reduction in the levels of sex hormone binding globulin ( SHBG ). The pituitary secretion of hormones is altered either due to a deficient peripheral feedback regulation or a concomitant central defect in the obese. Luteinizing hormone ( LH ) level may increase in some of the obese subjects. The secretion of LH in response to luteinizing hormone releasing hormone ( LHRH or GnRH ), clonidine and naloxone may be altered in obese women. The levels of circulating prolactin may fall along with a delay in the nocturnal surge of the hormone. The secretion of prolactin in response to thyrotropin releasing hormone ( TRH ), insulin-induced hypoglycemia, arginine and chlorpromazine is altered. Similarly growth hormone secretion in response to growth hormone releasing hormone ( GHRH ), clonidine, naloxone and arginine is also altered in obesity. The literature suggests an alteration in the autonomic nervous system activity and the metabolism of carbohydrates and fats in the obese. Steroid hormones could affect the distribution of fat in the various regions of the body, and the distribution of body fat is linked with the severity of hyperandrogenism and metabolic disorders in obese subjects. However, it is heartening to note that many of the endocrinological and reproductive disorders are reversible with weight reduction in the obese subjects.
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PMID:Reproductive functions in obese women. 837 28


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