Plasma gonadotrophins profile in relation to body composition in underprivileged boys

Abstract

The plasma concentrations of FSH and luteinizing hormone (LH) were measured in 250 underprivileged boys (UP boys) aged 9.0-15.9 yr living in state orphanage and in 357 clinically healthy boys of the same age (with weight and height between the 3rd and 97th percentile for Mexican standards) and correlated with chronological age (CA), weight, height, calculated lean body mass (LBM) and total body fat (TBF). On a group basis, UP boys had a 2 yr delay in the onset of clinical signs of puberty and a mild degree of malnutrition. In both groups of boys, the mean weights at time of initiation of the adolescent growth spurt in weight and at time of peak velocity of weight gain were very close to each other and similar to the values reported for Caucasian boys. The same phenomenon was true for their heights and the amounts of LBM and TBF (whether as an absolute value or as a percentage of body weight). Based on CA mean plasma FSH concentrations in UP boys were lower than normal from 11.0-13.9 yr and the subsequent steep rise of this hormone occurred 2 yr later than in healthy boys; however, when analyzed as a function of body weight, height or LMB, no such quantitative or qualitative differences emerged. Mean plasma LH concentrations in UP boys were higher than in healthy boys only up to certain CA (< 12.9 yr), weight (< 42.9 kg), height (< 147.0 cm), LBM (< 35.0 kg) or TBF (< 9.0 kg); however, no steep rise in plasma LH was observed in contrast to healthy boys. Although from a chronologic view point UP boys had a delayed onset in plasma gonadotropins changes, they did occur in association with the attainment of similar weight, height and LBM as in healthy boys. This observation seems to support further the hypothesis of a close association between a critical level of LBM (and not body fat) and the initiation of puberty both in healthy and multiply deprived boys.