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

The present study attempted to replicate and extend two recent studies that implicated aberrant brain 5-HT neurotransmission in the etiology of overeating and BW grain. Adult female rats received 25 mg/kg of desipramine hydrochloride 30--45 min prior to an intracisternal injection of 200 microgram (free base) of 5,7-DHT creatinine sulfate or its 1% ascorbic acid aqueous vehicle. After 7 weeks of measuring food intake, water intake, and BW change, rats from both groups received radiofrequency lesions of the MH or sham surgery. After 5 additional weeks of intake and BW measurements, all rats were tested for 24-hr acceptance of varying sucrose and quinine solutions and for 25-day acceptance of a high-fat replacement diet. While 5,7-DHT depleted brain 5-HT by 45%, it did not induce overeating and BW gain alone nor did it modify the overeating, obesity, or "finickiness" produced by hypothalamic injury. Several factors that relate to specificity, sufficiency, and compatibility with other 5-HT depletory techniques were discussed, as were factors of similarity and dissimilarity between this and the previous experiments that we attempted to replicate.
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PMID:Effects of central 5,7-dihydroxytryptamine on the medical hypothalamic syndrome in rats. 28 Feb 59

The hyperphagia characteristic of some types of obesity may result from a deficiency in one or more components of the systems controlling satiety which in rats may include the gastrointestinal hormone cholecystokinin (CCK). Obesity may also influence responsivity to often used central nervous system (CNS)-acting drugs and combination of drugs. In these experiments it was shown that: (1) Zucker fatty rats were less sensitive than lean to intraperitoneal injections of 20 U/kg CCK after a 6-hr fast and when reduced were less sensitive than lean and less sensitive than when obese to injections of 5 U/kg CCK; (2) Although fatties were equally sensitive as leans to injections of 0.5 and 1.0 mg/kg d-amphetamine sulfate, when reduced, they were less sensitive; (3) Injections of 1.25 and 2.5 mg/kg diazepam produced smaller increases in food intake after a 6-hr fast in fatty and reduced fatty than lean rats; (4) Combination of diazepam with cholecystokinin in both fatty and lean rats produced feeding similar to that following injection of carrier; and (5) A similar additive effect was obtained in both fatty and lean rats when diazepam was combined with amphetamine; however, the fatty appeared to be more sensitive to the amphetamine than the diazepam effect. Thus the Zucker fatty rat appears to be less sensitive to these chemicals which affect food intake, which supports the contention that their CNS is generally less responsive.
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PMID:Cholecystokinin, amphetamine and diazepam and feeding in lean and obese Zucker rats. 44 Oct 98

Published studies have shown that overproduction of very low density lipoproteins is a major factor leading to hypertiglyceridemia in obesity. Few systematic studies of triglyceride removal or postheparin lipoprotein lipase activity (LPLA) in obesity have appeared. We have examined heparin-released lipoprotein triglyceride hydrolase activities in 12 lean and 12 obese age- and sex-matched volunteers after overnight fasting. Heparin doses were calculated to compensate for the disproportionality between body mass and plasma volume in obesity. Triglyceride hydrolase activities of hepatic (HTGLA) and extrahepatic (LPLA) origin were distinguished by in vitro inhibition of LPLA with protamine sulfate. Incremental heparin doses were given to each subject to determine lipase activities under conditions of maximal release and to define sensitivity to heparin-facilitated lipase release. Maximal postheparin LPLA and HTGLA (u/ml plasma or u/total plasma vol) were similar in lean and obese individuals despite a nearly three-fold increase in calculated adipose tissue mass in the obese. Since adipose tissue LPLA has been reported to increase in proportion to adipocyte size, the lack of difference in maximal postheparin LPLA was expected. There was an inverse correlation between plasma triglyceride concentration and LPLA/kg adipose tissue. These empirical observations may reflect relatively decreased heparin-releaseable (functional) LPLA in relation to adipose organ mass in obese subjects. The mechanism of this relationship has not been established.
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PMID:Postheparin plasma lipase activities in obesity: failure to increase with adipose organ enlargement. 68 71

To explore recent suggestions that genetically obese Zucker rats show less anorexia when brain gamma-aminobutyric acid (GABA) is elevated, obese vs. lean littermates received 100, 50 and 0 micrograms of the GABA-transaminase inhibitor, ethanolamine-O-sulfate (EOS), intra-cisternally in a longitudinal design where their feeding patterns were monitored 24 h daily. Obese rats were refractory to EOS-induced anorexia as evidenced by less suppression of daily food intake and fewer alterations to both meal size and meal frequency, particularly in the night. This effect was not due to an inability of EOS to increase brain GABA since equivalent, specific dose-dependent increments were seen in the brains of separate obese vs. lean rats after analysis of endogenous GABA and seven other amino acids. An unexpected finding was elevated levels of brain taurine for obese rats regardless of EOS dosage, implying a hitherto unknown neurochemical trait whose potential significance is unclear. The primary data obtained provide further support for recent hypotheses that obese Zucker rats possess altered brain GABAergic mechanisms that may serve as one contributor to their over-eating.
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PMID:Effects of increasing brain GABA on the meal patterns of genetically obese vs. lean Zucker rats. 132 68

A well-established epidemiologic association exists between hyperinsulinemia and macrovascular disease. However, the mechanism or mechanisms by which hyperinsulinemia promotes atherogenesis is unknown. Recent evidence indicates that the adrenal steroid dehydroepiandrosterone (DHEA) exerts multiple antiatherogenic effects and also suggests that hyperinsulinemia may reduce serum DHEA and DHEA-sulfate levels by decreasing production and enhancing metabolic clearance. We advance the hypothesis that hyperinsulinemia promotes macrovascular disease in part by reducing serum DHEA and DHEA-sulfate levels and illustrate how this may be the case in two clinical conditions characterized by hyperinsulinemic insulin resistance: aging and obesity.
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PMID:Dehydroepiandrosterone: the "missing link" between hyperinsulinemia and atherosclerosis? 138 59

Disorders of the adrenal cortex and medulla can result in glucose intolerance or overt diabetes mellitus. Cushing's syndrome, characterized by excessive secretion of glucocorticoids, impairs glucose tolerance primarily by causing insulin resistance at the post-receptor level. On the other hand, phaeochromocytoma and hyperaldosteronism, via the respective actions of catecholamines and hypokalaemia on the pancreatic beta-cell, impair glucose tolerance primarily by inhibiting insulin release. The glucose intolerance associated with these adrenal disorders is usually only mild to moderate in severity. Marked hyperglycaemia, glycosuria, and polyuria are uncommon and ketosis is rare. Moreover, the late complications of diabetes mellitus are distinctly uncommon in patients with these disorders, and the prognosis for morbidity and death is usually that of the underlying disease and not that of diabetes mellitus. The impaired glucose tolerance induced by all three of these adrenal disorders usually returns to normal once the underlying aetiology has been cured. These factors must guide the clinician in treatment of these secondary forms of diabetes, and suggest that tight (near normal) blood glucose control may not be an appropriate goal in patients with these disorders. The relationship between adrenal androgens and glucose tolerance is more uncertain. Several studies in humans have demonstrated an acute decline in serum concentrations of the adrenal steroids DHEA and DHEA-sulfate in response to experimentally-induced hyperinsulinaemia, but the regulatory role of insulin on adrenal androgen metabolism in normal physiology or disease remains speculative. In several animal models DHEA appears to exert potent anti-obesity and anti-diabetogenic actions, but such effects have yet to be demonstrated in humans. Human studies of DHEA are limited, and more research needs to be conducted to determine whether the observations made in animal models will prove applicable to man.
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PMID:Diabetes and adrenal disease. 144 72

Estrogen replacement therapy is widely used to treat menopausal symptoms and prevent osteoporosis. The mechanism of these and other estrogen effects is currently under investigation. We studied the plasma steroid hormone and sex hormone binding globulin levels in frozen plasma obtained from 977 women aged 50 to 79 years from 1972 to 1974. Almost all of the 301 women who reported current use of noncontraceptive estrogen were taking conjugated estrogen by mouth; none reported use of a progestin. Women taking estrogen were significantly younger, thinner, and more likely to smoke cigarettes than women not taking estrogen. Sex hormone binding globulin and all endogenous hormones except testosterone were negatively correlated with age; estradiol was positively and cortisol and sex hormone binding globulin were negatively associated with obesity. After adjusting for age and obesity, dehydroepiandrosterone sulfate, androstenedione, and free testosterone were significantly lower in women currently taking estrogen than in women not using estrogen. These differences were independent of cigarette smoking. As expected, estrogens (including free estradiol), sex hormone binding globulin, and cortisol levels were higher in treated than untreated women. The possibility that some of the benefits and risks of replacement estrogen are secondary to altered adrenal steroid metabolism and androgen levels needs further evaluation.
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PMID:Exogenous estrogen and endogenous sex hormones. 154 58

Zinc has recently been found to have important effects on metabolism and thermoregulation of obese individuals. The effects of zinc sulfate and thyroxine treatment on the obese patients were studied. The obese patients, selected from outpatients at the Taichung VGH, all had their body weight 20% higher than they normally should have, and body mass indexes (BMI = Wt/Ht2) greater than 25 kg/m2. They were separated into three groups to have 600mg zinc sulfate or/and 0.1mg thyroxine per day, respectively. Serum zinc and copper contents were determined by atomic absorption spectrometer. The alterative of body weight was also recorded. After 8 weeks of therapy, the zinc sulfate and zinc sulfate + thyroxine treatment had more significant effects on weight reduction (male: -1.10 +/- 0.38; -1.10 +/- 0.19, female: -1.75 +/- 0.19; -3.16 +/- 0.21 kg, P less than 0.05, respectively). The serum zinc content was found to inversely relate to the body weight reduction (r = -0.605, P less than 0.001). The results also showed that zinc sulfate and thyroxine treatment did not have satisfactorily greater effects on body weight reduction at short-term therapy on obese patients. We conclude that zinc therapy on the obese patients still need more evaluation and suggest that zinc may have important effects on the thyroid hormones conversion, and may have certain regulatory effects on the insulin activity through its interaction with thyroid hormones in the development of obesity.
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PMID:[Zinc sulfate and thyroxine treatment on the obese patients]. 165 39

Cholecystokinin octapeptide sulfate (CCK 8 S) appears to act via a serotonergic mechanism on several behavioral paradigms, including satiety. In the present study, CCK 8 S was found to induce slight nonsignificant serotonergic changes in hypothalamic nuclei of the normal rat. In the "cafeteria" rat, however, it increased both 5-HT and 5-HIAA levels in the ventromedial hypothalamus (VMH), 5-HT levels in the paraventricular nucleus (PVN) and decreased 5-HIAA levels in the dorsomedial hypothalamus (DMH). These data suggest that the primary site of action of CCK 8 S is in the median hypothalamus, contrasting with an absence of effect in the lateral hypothalamus (LH). The involvement of 5-HT in the effect of CCK 8 S is further suggested. However, the relationship between these neurochemical changes and CCK 8 S-induced satiety is not clear. Nonetheless, a special sensitivity to CCK 8 S of the obese "cafeteria" rat is evidenced, which contrasts with a reduced response of genetic obesity models.
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PMID:Cholecystokinin-induced variations in hypothalamic serotonergic system of the "cafeteria" rat. 170 63

To evaluate the hypothesis that endocrine profiles change with aging independently of specific disease states, we examined the age trends of 17 major sex hormones, metabolites, and related serum proteins in 2 large groups of adult males drawn from the Massachusetts Male Aging Study, a population-based cross-sectional survey of men aged 39-70 yr conducted in 1986-89. Group 1 consisted of 415 men who were free of obesity, alcoholism, all prescription medication, prostate problems, and chronic illness (cancer, coronary heart disease, hypertension, diabetes, and ulcer). Group 2 consisted of 1294 men who reported 1 or more of the above conditions. Each age trend was satisfactorily described by a constant percent change per yr between ages 39-70 yr. Free testosterone declined by 1.2%/yr, and albumin-bound testosterone by 1.0%/yr. Sex hormone-binding globulin (SHBG), the major serum carrier of testosterone, increased by 1.2%/yr, with the net effect that total serum testosterone declined more slowly (0.4%/yr) than the free or albumin-bound pools alone. Among the major androgens and metabolites, androstane-3 alpha,17 beta-diol (androstanediol; 0.8%/yr) and androstanediol glucuronide (0.6%/yr) declined less rapidly than free testosterone, while 5 alpha-dihydrotestosterone remained essentially constant between ages 39-70 yr. Androstenedione declined at 1.3%/yr, a rate comparable to that of free testosterone, while the adrenal androgen dehydroepiandrosterone (3.1%/yr) and its sulfate (2.2%/yr) declined 2-3 times more rapidly. The levels of testosterone, SHBG, and several androgen metabolites followed a parallel course in groups 1 and 2, remaining consistently 10-15% lower in group 2 across the age range of the study. Subgroup analyses suggested that obese subjects might be responsible for much of the group difference in androgen level. Serum concentrations of estrogens and cortisol did not change significantly with age or differ between groups. Of the pituitary gonadotropins, FSH increased at 1.9%/yr, LH increased at 1.3%/yr, and PRL declined at 0.4%/yr, with no significant difference between groups 1 and 2.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Age, disease, and changing sex hormone levels in middle-aged men: results of the Massachusetts Male Aging Study. 171 16


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