Hypothalamo-pituitary-gonadal axis in children with chronic renal failure.

Delayed puberty in children with chronic renal failure (CRF) may be due to gonadal dysfunction, increased plasma binding of gonadal hormones, or changes of the hypothalamo-pituitary axis. Plasma androgens were studied in 17 prepubertal boys with preterminal CRF. In addition, the response of luteinizing and follicle-stimulating hormones (LH, FSH) to luteinizing-releasing hormone (LHRH) was followed in the plasma of these boys and of 12 prepubertal girls with CRF. Plasma testosterone (T) was significantly lower in the CRF boys than it was in the controls (mean, 9 vs. 22 ng/ml) and concerned also the free T fraction (2.5% in both groups). Dihydro-T was similarly reduced in CRF, resulting in a normal T/DHT ratio. Basal plasma LH levels were significantly elevated in boys (1.0 vs. 0.5 ng/ml) and in girls with CRF (1.4 vs. 0.4 ng/ml), whereas mean basal FSH values were similar to controls. After LHRH administration, peak levels of LH and FSH were not different in CRF and control children; however, the absolute differences from basal to peak values were lower in CRF. These findings may indicate that Leydig cell dysfunction in CRF already occurs before the onset of puberty. The blunted LH and FSH responses to LHRH suggest an additional disturbance at the hypothalamo-pituitary level.