44 research outputs found

    The Stature of Boys Is Inversely Correlated to the Levels of Their Sertoli Cell Hormones: Do the Testes Restrain the Maturation of Boys?

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    The testes of preadolescent boys appear to be dormant, as they produce only trace levels of testosterone [1]. However, they release supra-adult levels of Müllerian Inhibiting Substance (MIS, anti-Müllerian hormone) and lesser levels of inhibin B (InhB), for unknown reasons [2], [3]. Boys have a variable rate of maturation, which on average is slower than girls. The height of children relative to their parents is an index of their maturity [4], [5]. We report here that a boy's level of MIS and InhB is stable over time and negatively correlates with his height and his height relative to his parent's height. This suggests that boy's with high levels of MIS and InhB are short because they are immature, rather than because they are destined to be short men. The levels of MIS and InhB in the boys did not correlate with known hormonal modulators of growth, and were additive with age and the growth hormone/IGF1 axis as predictors of a boy's height. If MIS and InhB were causal regulators of maturity, then the inter-boy differences in the levels of these hormone produces variation in maturation equivalent to 18-months of development. MIS and InhB may thus account for most of the variation in the rate of male development. If boys lacked these hormones, then an average 5-year-old boy would be over 5 cm taller than age-matched girls, making boys almost as dimorphic as men, for height. This indicates that boys have a high growth potential that is initially suppressed by their testes. The concept of the childhood testes suppressing an adult male feature appears paradoxical. However, the growth of children requires intergenerational transfer of nutrients. Consequently, the MIS/InhB slowing of male growth may have been historically advantageous, as it would minimizes any sex bias in the maternal cost of early child rearing

    Metformin reduces serum mullerian-inhibiting substance levels in women with polycystic ovary syndrome after protracted treatment

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    Objective: Assessment of ovarian responses to metformin treatment in obese women with polycystic ovary syndrome (PCOS). Design: Prospective treatment with randomization to two doses of metformin. Setting: University teaching hospital. Patient(s): Obese women (n = 82) with PCOS. Intervention(s): Markers of ovarian function were assessed after 4 and 8 months. Main Outcome Measure(s): Hormone (androgens and mullerian-inhibiting substance [MIS]) changes over time. Result(s): There was no difference in the reproductive hormone changes between the doses of metformin, and data were combined for further analyses. Significant responses to treatment were recorded for menstrual frequency and androstenediona (A) (reduction) within the first 4 months of treatment. However, suppression of the elevated circulation MIS concentrations required protracted treatment, because no change was observed in the first 4 months-only in the second 4-month assessment period. Conclusion(s): Metformin treatment PCOS leads to rapid suppression of A and improved menstrual frequency. Suppression of MIS is a delayed response that may be secondary to the development of a cohort of follicles that underwent initial recruitment in an environment of reduced insulin stimulation. (C)2005 by American Society for Reproductive Medicine
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