No abstract

The effect of methylenedianiline on testicular 17-oxosteroid secretion caused by pregnant mare serum (PMS) was evaluated by measurements of 17-oxosteroids in the spermatic vein blood of the dog. Testicular 17-oxosteroid secretion in dogs which received a single injection of PMS (2,000 per animal) into the saphenous vein increased markedly and reached the maximum within approximately 90 minutes after the injection; the increase in secretion tended to be maintained over 4 hours of observation.At the highest rate of secretion, an intravenous injection of methylenedianiline (20 or 60mg/kg) into these dogs brought about a rapid decline in the output of testicular 17-oxosteroids.The response was reversible. These results show that methylenedianiline can prevent the augmented secretion of testicular 17-oxosteroids caused by pregnant mare serum.Methylenedianiline has been shown to diminish the secretion of 17-hydroxycorticsteroids from the adrenal in dogs.1 In a previous work,2 we have demonstrated that the stimulating effect of human chorionic gonadotrophin (HCG) on testicular 17-oxosteroid secretion is inhibited by methylenedianiline. It appears that the effect of methylenedianiline depends on a direct inhibition of androgen biosynthesis in testicular tissue. In this paper, the effect of methylenedianiline on testicular 17-oxosteroid secretion in response to pregnant mare serum will be presented. EXPERIMENTAL METHODSAdult male mongrel dogs 8.7-18.1kg in weight were used. Spermatic vein cannulation.The cannulation was done by a slight modification of the technique3 previously described.The dogs were anesthetized with an intravenous injection of 25mg/kg sodium pentobarbital and maintained by supplement of the drug as required.Through a longitudinal incision in the left lumbar area, the left spermatic vein and left lumbo-adrenal vein were exposed, and after systemic administration of heparin, the vessels were connected to a T-shaped glass cannula fitted with a rubber tube, so that the blood from the testis could flow through the spermatic vein to the lumbo-adrenal vein during periods when blood was not being collected.