Some observations on the excretion of 17-ketosteroids and 17-ketogenic steroids by guinea-pigs.

Abstract

SUMMARY 1. 17-Ketosteroids (KS) and 17-ketogenic steroids (KG) may be determined in guinea-pig urine by the method of Norymberski, Stubbs & West [1953]. Studies on the fractionation of urinary steroids showed the method was applicable to the urine of pregnant guinea-pigs. 2. So little material in the faeces of guinea-pigs behaved as KS that excretion by this route may be ignored. 3. Daily vaginal lavages shortened the oestrous cycle in the guinea-pig and abolished the peak of KS excretion seen at oestrus in normal cycles. No consistent trend in the excretion of KG was seen during normal oestrous cycles. No cyclical change in KS excretion was seen after ovariectomy. 4. During pregnancy in the guinea-pig, there was a rise in the excretion of KG and KS. The increase was not abolished by ovariectomy. The rise did not occur in one adrenalectomized animal which went to term, though it continued to excrete significant amounts of KS. The contribution of the foetal adrenals to the excretion of steroids by the pregnant mother was probably small. 5. Non-specific adrenal stimulation caused a rise in the urinary excretion of KS and KG. 6. Fractionation of the KS released from the urine of an intact non-pregnant guinea-pig by a mild hydrolytic procedure gave five major compounds, one in the 11-deoxy and four in the 11-oxy fraction. All five compounds were excreted in increased amounts by a pregnant intact and by a pregnant adrenalectomized guinea-pig.