Investigation of Peripheral Androgen Resistance in Genital Hypoplasia associated with Congenital Growth Hormone Deficiency

In a male infant with congenital growth hormone deficiency and genital hypoplasia (micropenis, cryptorchidism and small scrotum) androgen receptors, tissue specific 5 alpha reductase and steroid excretion pattern were determined in order to test the hypothesis of peripheral androgen resistance. A reduced number of cytosolic binding sites (Nmax) was found for the T and DHT receptor in patients foreskin compared to controls (n = 9) of similar age. The specific affinity (Kd) of the cytosolic receptor, however, was normal. Tissue specific 5 alpha reductase determination revealed a Vmax of 3.3 pmol/mg/h (controls 15.8 +/- 1.4). Analysis of urinary steroid excretion pattern revealed decreased levels of T metabolites, indicating impaired T metabolism. We postulate, that genital hypoplasia in patients with congenital GH deficiency is associated with impaired target organ responsiveness to androgen hormones caused by abnormalities within the pathway of intracellular reactions of T utilization.