The Journal of clinical endocrinology and metabolism
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J. Clin. Endocrinol. Metab. · Sep 2004
Randomized Controlled Trial Multicenter Study Clinical TrialSafety and efficacy of anastrozole for the treatment of pubertal gynecomastia: a randomized, double-blind, placebo-controlled trial.
Pubertal gynecomastia is thought to result from transient imbalances between estrogen and androgen concentrations. Anastrozole (ARIMIDEX), a potent and selective aromatase inhibitor, decreases estrogen and increases testosterone concentrations in pubertal boys. The safety and efficacy of anastrozole for the treatment of pubertal gynecomastia were evaluated. ⋯ At 6 months, the median percent change in the testosterone/estradiol ratio was 166% for the anastrozole group and 39% for the placebo group. Anastrozole treatment was well tolerated. In patients with pubertal gynecomastia, no significant difference in the percentage of patients with a 50% or greater reduction in total breast volume, as calculated from ultrasonography measurements, was demonstrated between the anastrozole and placebo groups.
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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
Randomized Controlled Trial Clinical TrialNon-acylated ghrelin counteracts the metabolic but not the neuroendocrine response to acylated ghrelin in humans.
Ghrelin possesses strong GH-releasing activity but also other endocrine activities including stimulation of PRL and ACTH secretion, modulation of insulin secretion and glucose metabolism. It is assumed that the GH secretagogue (GHS) receptor (GHS-R) 1a mediates ghrelin actins provided its acylation in Serine 3; in fact, acylated ghrelin only is able to exert endocrine activities. Acylated ghrelin (AG) is present in serum at a 2.5 fold lower concentration than unacylated ghrelin (UAG). ⋯ In conclusion, non-acylated ghrelin does not affect the GH, PRL, and ACTH response to acylated ghrelin but is able to antagonize the effects of acylated ghrelin on insulin secretion and glucose levels. These findings indicate that unacylated ghrelin is metabolically active and is likely to counterbalance the influence of acylated ghrelin on insulin secretion and glucose metabolism. As GHS-R1a is not bound by unacylated ghrelin, these findings suggest that GHS receptor subtypes mediate the metabolic actions of both acylated and unacylated ghrelin.