Overnight gonadotropin excretion in normal females

FSH and LH in acetone precipitates of timed overnight urine collections were measured by radioimmunoassay. FSH and LH urinary excretion extrapolated to 24 h was determined in 140 normal girls 3-16 years. Timed overnight urines were collected throughout a menstrual cycle from 3 normal adult women. FSH and LH progressively increased with age from 2.0 +/- 0.5 (FSH) and 2.0 +/- 0.4 (LH) IU/24 h for the 3--4 yr age group to 8.1 +/- 1.8 (FSH) and 11.5 +/- 3.8 (LH) IU/24 h for the 15--16 yr age group. Mean FSH and LH excretion for succeeding age groups (3--4, 5--6, 7--8, 9--10, 11--12, 13--14 and 15--16 years) increased significantly for the 5--6, 9--10 and 11--12 year age groups. Mean LH but not FSH excretion increased significantly for the 13--14 year age group. FSH and LH excretion increased progressively with stage of sexual development. In the 3 girls with established menstrual cycles. FSH (43.6 +/- 5.0 IU/24 h) and LH (113.7 +/- 7.8 IU/24 h) peaks occurred on the same day. Luteal phase excretion of FSH and LH was significantly lower than follicular phase excretion. Timed overnight urine collection allows integration of several hours of FSH and LH excretion.