The Journal of clinical endocrinology and metabolism
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J. Clin. Endocrinol. Metab. · Sep 2004
ReviewDiet, insulin resistance, and obesity: zoning in on data for Atkins dieters living in South Beach.
Insulin resistance is a central pathogenic factor for the metabolic syndrome and is associated with both generalized obesity and the accumulation of fat in the omental and intramyocellular compartments. In the context of the current obesity epidemic, it is imperative to consider diets in terms of their ability to both promote weight loss and ameliorate insulin resistance. Weight loss under any dietary formulation depends on hypocaloric intake, and only moderate weight loss (5-10%) is sufficient to augment insulin sensitivity. ⋯ Popular low-carbohydrate, high-fat diets are being fervently embraced as an alternative to challenging modifications in lifestyle and intentional calorie reduction. Current data do not support such unbridled enthusiasm for these diets, particularly in relationship to high-fiber, high-carbohydrate diets emphasizing intake of fresh vegetables and fruits. Long-term studies to determine the efficacy and safety of both popular and experimental diets are warranted.
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J. Clin. Endocrinol. Metab. · Jul 2004
Randomized Controlled Trial Clinical TrialRegulation of the somatotropic axis by intensive insulin therapy during protracted critical illness.
The catabolic state of critical illness has been linked to the suppressed somatotropic GH-IGF-binding protein (IGFBP) axis. In critically ill patients it has been demonstrated that, compared with the conventional approach, which only recommended insulin therapy when blood glucose levels exceeded 12 mmol/liter, strict maintenance of blood glucose levels below 6.1 mmol/liter with intensive insulin therapy almost halved intensive care mortality, acute renal failure, critical illness polyneuropathy, and bloodstream infections. Poor blood glucose control in diabetes mellitus has also been associated with low serum IGF-I levels, which can be increased by insulin therapy. ⋯ In conclusion, our data suggest that intensive insulin therapy surprisingly suppressed the somatotropic axis despite its beneficial effects on patient outcome. GH resistance accompanied this suppression of the IGF-I axis. To what extent and through which mechanisms the changes in the GH-IGF-IGFBP axis contributed to the survival benefit under intensive insulin therapy remain elusive.
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J. Clin. Endocrinol. Metab. · Jul 2004
Assay variation confounds the diagnosis of hypovitaminosis D: a call for standardization.
Endemic hypovitaminosis D contributes to osteoporosis development. However, variation in 25-hydroxyvitamin D (25OHD) measurement is reported and confounds the diagnosis of vitamin D insufficiency/deficiency. This report emphasizes the marked variability observed in serum 25OHD measurements between laboratories. ⋯ Similarly, the mean increase produced by spiking with 20 ng/ml ranged from 7.7-18.0 ng/ml. In conclusion, 25OHD assays yield markedly differing results; whether an individual is found to have low or normal vitamin D status is a function of the laboratory used. If the medical community is to make progress in correcting widespread hypovitaminosis D, 25OHD measurement must be standardized.
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J. Clin. Endocrinol. Metab. · Jul 2004
Hormonal and body composition predictors of soluble leptin receptor, leptin, and free leptin index in adolescent girls with anorexia nervosa and controls and relation to insulin sensitivity.
Anorexia nervosa (AN) is associated with very low levels of leptin, a cytokine secreted by adipose tissue and known to suppress appetite. Leptin may play a permissive role in onset of puberty and in resumption of gonadal function in conditions of undernutrition. The soluble leptin receptor (sOB-R) is the main leptin binding protein, and the ratio of serum leptin to sOB-R provides a measure of the free leptin index (FLI), which may be a more accurate determinant of leptin function. ⋯ Levels of leptin and FLI, conversely, are primarily predicted by body composition. Weight recovery is associated with a decrease in sOB-R and an increase in leptin. Resumption of menses is associated with significant increases in the FLI, suggesting that free leptin may be an important determinant of menstrual recovery.
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J. Clin. Endocrinol. Metab. · Jun 2004
Clinical TrialEarly adrenocortical recovery after glucocorticoid therapy in children with leukemia.
The duration of glucocorticoid-induced inhibition that occurs in the hypothalamic-pituitary-adrenal (HPA) axis after discontinuation of treatment is controversial. The main objective of this prospective study was to evaluate the inhibition of the HPA axis by dexamethasone in children and adolescents with acute lymphoid leukemia. Thirty-five patients (median age of 6.9 yr) were evaluated. ⋯ Suppression of the adrenal function was detected during glucocorticoid therapy, which persisted for 48 h after the steroid was removed from treatment (P < 0.01). One month after ceasing the administration of the glucocorticoid, the adrenal function was similar to that before glucocorticoid therapy. According to these results, a clinical and laboratory follow-up of the HPA axis in the month after the cessation of dexamethasone therapy is suggested to determine glucocorticoid replacement.