The urinary excretion of dehydroepiandrosterone (DHA), oestrone (OE1) and 17β-oestradiol (OE2) has been estimated during the administration of a number of hormones to an intact mature male pig. Daily intramuscular injections of corticotrophin (300 IU) or cortisone acetate (500 mg) resulted in a decrease in the levels of OE1, OE2 and DHA. Following the daily injection of human chorionic gonadotrophin (2500 IU) the excretion of all three steroids increased greatly. The daily oral administration of 30 mg Norlutin acetate (17α-ethynyl-19-nortestosterone acetate) appeared to be more effective than 30 mg Norlutin (17α-ethynyl-19-nortestosterone) in suppressing steroid production by the boar.
Considerable daily variation occurred in the amounts of OE1, OE2 and DHA excreted in the urine during »control« periods, and some evidence of a seasonal variation in levels of urinary steroids was observed.
Throughout the investigation a high degree of correlation existed between the urinary excretion of DHA and both oestrogens. It was concluded that the data provide strong support for the view that the large quantities of DHA in the urine of the normal boar arise from steroid biosynthesis in the testes.