Abstract
Three androgen levels in the blood plasma of male dogs, following an intramuscular injection of hexestrol dicaprylate (H8) were assayed and the state of spermatogenesis was examined in four of them. Sixteen male dogs were injected with a single dose of 0.5 mg/kg of H8, and 4-androstenedione (A), testosterone (T), and 5α-dihydrotestosterone (DHT) in peripheral and/or spermatic vein plasma were measured by radioimmunoassay technics.
The results obtained were summarized as follows.
1. The 3 androgen levels in both peripheral and spermatic vein plasma of 12 dogs showed prompt, rapid decrease following the injection of H8, and each decrease of peripheral plasma level of A, T, and DHT showed parallel to that in spermatic vein plasma.
2. After administration of H8, at least up to the 2 months period, each plasma level of these 3 androgens was kept very low, and spermatogenesis was not observed in this duration in all of 4 dogs examined. Whereas, between the 70th and 150th day, these androgen levels elevated sharply to attain the peaks, which were higher than the levels at each pre-injection time. Recovery of sperma-togenetic function was observed in each dog around the peak of blood androgen level.
These findings suggest that injected H8 influenced to inhibit spermatogenesis by interfering with androgen production in the interstitial tissue of testis in the male dogs.
