Studies on the excretion of oestrogens by pregnant ewes

Abstract

Adaptations of standard methods are described for the preparation of oestrogenic extracts from the urine and faeces of sheep. The extracts were separated into strong phenols, non-ketonic weak phenols, and ketonic weak phenols. The concentration of oestrogen in these fractions was determined by bioassay. Special consideration was given to the accuracy of the methods in light of the findings of Friedgood, Garst, and Haagen-Smit (1948). Four ewes were examined for urinary excretion only and seven ewes for both faecal and urinary excretion throughout pregnancy. Little or no excretion occurred until the last three or four weeks of pregnancy and even then the levels were consistently low. The faecal levels were higher than those of the urine. With one or two possible exceptions no strongly phenolic oestrogen was detected. Generally, the ketonic oestrogen (calculated as oestrone) of both urine and faeces was higher than the non-ketonic oestrogen (as oestradiol). The daily levels observed during the last few weeks of pregnancy lay within the following ranges: urinary "oestradiol" <0.2-3 µg., "oestrone" <1.5-20 µg.; faecal "oestradiol" 1-20 µg., "oestrone"; 1-100 µg. The faecal oestrogen was not conjugated. Exploratory tests were made on ovaries, bile, and placentae. In all cases the oestrogen levels were low and both ketonic and non-ketonic activity was noted. In the bile most of the activity was fonnd in the conjugated form. No pregnanediol was found in the urine samples.