Serum inhibin concentrations rise throughout normal male and female puberty.

Using a newly developed, sensitive, and specific RIA, we measured the serum concentrations of inhibin, together with those of FSH, LH, and sex steroids, throughout puberty in 99 boys and 102 girls attending a suburban Melbourne school. Serum inhibin levels rose from a geometric mean level of 161 U/L (range, 87-310; 67% confidence interval) at stage I puberty in boys to 442 U/L (range, 300-626) at stage V, while corresponding values in girls were 97 U/L (range, 46-204) and 231 U/L (range, 187-372), respectively. Serum inhibin concentrations were strongly correlated with age and serum FSH, LH, testosterone, and estradiol; all hormones increased in parallel in both boys and girls. After adjustment for age, the partial correlation coefficients remained significant only for testosterone in the boys. We hypothesize that gonadal inhibin production is stimulated by rising gonadotropin levels during pubertal development.