Blood Production Rate of Dihydrotestosterone in the Syndrome of Male Pseudohermaphroditism with Testicular Feminization

ABSTRACT

The constant infusion technique was used to determine the metabolic clearance rate (MCR) and the blood production (PB) of dihydrotestosterone (DHT) in patients with testicular feminization as compared to those of normal adult men and women. The transfer constants ([ρ]_BB) of testosterone (T) and adrostenedione (Δ) to that of DHT were also determined.

Our data confirmed that the patients had plasma concentrations of T and DHT which were within or slightly above the normal range for adult men.

The mean (±sd) MCR^DHT of patients with testicular feminization was similar to that of normal women and significantly lower than that of normal men (patients: 163 ± 22 L/M²/24 hr; women: 157 ± 27 L/M²/24 hr; men: 343 ± 93 L/M²/24 hr). The same relationship was observed for the mean (±sd) MCR^T (patients: 403 ± 33L/M²/24 hr; women: 383 ± 42 L/M²/24 hr; men: 581 ± 64 L/M²/24 hr) whereas no significant difference was found in MCR^Δ of the three groups.

The mean, (±sd) PB^DHT of the patients was within the range of that of normal males but significantly higher than that of normal women (patients: 197 ± 97 μg/24 hr; women: 41 ± 6 μg/24 hr; men: 343 ± 148 μg/24 hr). The same relationship was found for PB^T but no significant difference was found in PB^Δ of patients and normal subjects of both sexes.

The transfer constants of T and Δ to DHT in patients were similar to those of normal women but lower than those of normal men. From these values and those of blood productions of T, Δ and DHT, it was calculated that practically all PB^DHT in normal women originated from the peripheral conversion of T and Δ.

In contrast PB^T and PB^Δ of normal males and in patients contributed 73% and 45% to PB^DHT, respectively; these results agree with previous investigations demonstrating that the testes of patients with testicular feminization secrete some DHT.