Delayed puberty in uremia: pituitary-gonadal function during short-term pulsatile luteinizing hormone-releasing hormone administration.

Pubertal development is frequently delayed or disordered in children with chronic renal failure. Both neuroendocrine and peripheral alterations due to uremia have been hypothesized to explain the impairment in the pituitary gonadal axis. The aim of the present study was to evaluate quantitative (immunological) and qualitative (biological) LH secretion, as well as FSH and sex steroids, before and during 7 days of sc LHRH administration (136-150 ng/kg bw every 120 min) in 5 uremic children (13.1-14.8 yr) with delayed puberty. Six nonuremic children (13.2-17.8 yr) with delayed puberty underwent the same schedule and served as control group. On day 0 mean immunoreactive LH (I-LH) levels were higher in uremic (4.5 +/- 0.9 mIU/ml) than in nonuremic (1.9 +/- 03 mIU/ml; p < 0.05) subjects while no differences were observed in bioactive LH (B-LH) levels (2.9 +/- 0.7 mIU/ml vs 2.4 +/- 0.3 mIU/ml). In both groups of subjects testosterone was at prepubertal levels. Spontaneous I-LH and B-LH pulses were observed sporadically in both uremic and nonuremic subjects. Short-term pulsatile LHRH administration induced significant increases in B-LH, I-LH, FSH and testosterone. The B/I LH ratio increased from day 0 (0.7 +/- 0.2) to day 7 (1.3 +/- 0.4; p < 0.05) in uremics while it showed wide fluctuations in nonuremic subjects. On day 7, 4 uremic and 5 nonuremic subjects showed a pulsatile release of B-LH after exogenous LHRH pulses. Our data document that in uremia there are qualitative as well as quantitative abnormalities in pituitary gonadal secretion.(ABSTRACT TRUNCATED AT 250 WORDS)