ABSTRACT
Female gymnasts have a delayed onset and probably retarded progression of puberty. The aim of this study was to test the hypothesis that the delay in onset of puberty in gymnasts as compared to girl swimmers is modulated by a lower estrone level due to a smaller amount of body fat. The sex-hormone and gonadotropin levels of 46 gymnasts and 37 girl swimmers of the same biological maturation (breast development: M = 1 or M = 2) were studied. In each subject the following hormones were measured in plasma: estrone, 17-beta-estradiol, DHEAS, testosterone, androstenedione, LH, and FSH. In prepubertal children (M = 1) the levels of estrone, testosterone, and androstenedione were lower in the gymnastic group as compared to the swimming group. In the early pubertal (M = 2) gymnastic and swimming groups these hormone levels were no longer different. The other hormone levels were not significantly different in either the prepubertal groups or the early pubertal ones. Within the total prepubertal group there is a clear relationship between the estrone levels and the levels of testosterone and androstenedione, but not between estrone and 17-beta-estradiol, nor between the calculated fat mass and any of the hormone levels. It appears that the androstenedione and testosterone levels are responsible for the difference in estrone level, rather than the amount of body fat.
