Excretion of 14C in Urine of the Domestic Sow after Injection of Radioactive Estradiol-17β, Estrone, Corticosterone and Cortisol

Two yearling sows, one intact and one ovariectomized, were used to determine the rate of excretion in urine of 14C following intravenous injection of 14C-steroids. Estradiol-17 β-4-14C (2.26 μc) and estrone-4-14C (2.12 μc) were singly injected into the intact sow during two estrous periods. The interval between injections was 6 weeks. Five months later corticosterone -4-14C (4.74 μc) and cortisol-4-14C (4.41 μc) were singly injected on day 19 of two successive estrous cycles. Only cortisol-4-14C (4.25 μc) was injected into the ovariectomized sow. Radioactivity appeared in the urine of both sows within the first 10 min. after injection of each steroid. Recoveries of 14C in urine of the intact sow 144 to 168 hr. after injection were 89, 86, 80 and 79%, respectively, for estradiol-17β estrone, corticosterone and cortisol. The ovariectomized sow excreted in urine 97% of the injected 14C-cortisol in 120 hours. Twelve hours after injection of the intact sow 64% of the 14C from cortisol and 33% of the 14C from corticosterone had been recovered in the urine. Excretion of 14C from estrone was considerably greater for the first 10 min. as compared to estradiol-17 β but total recovery of 14C in urine for the latter compound by 12 hr. was greater (79% vs. 70%).