The Oestrous Hormone in the Urine of Pregnant Cows.

Abstract

Through the kindness of Dr. L. J. Cole of the Genetics Department a number of pregnant cows were placed at our disposal to make a quantitative study of hormones in the urine. One of the points of interest found in this study was the great amount of the oestrous hormone present. A quantitative determination of the oestrous hormone in the urine of pregnant women has been recently reported by Veler and Doisy. Ascheim and Zondek have mentioned the presence of this hormone in the urine of pregnant cows. The data presented in this report are concerned with the quantitative relationship between the oestrous hormone in the urine of cows and the time of pregnancy. Twenty-four hour samples of the urine were collected and the hormone extracted with ether and then taken up in Mazola oil. A second method was also used in which the urine was neutralized, Berkefelded and injected without further treatment. The method of assaying the hormone was that of Allen and Doisy, rats being used as test animals. The results obtained by these procedures are presented in the accompanying tables. In general the amount of the oestrous producing hormone increases as pregnancy progresses. The data seem to indicate an enormous increase of the hormone in the later days of pregnancy with a sudden decrease to little or none within the first 24 hours after parturition. Close analysis of the data shows certain discrepancies between them and the general statement just made. Cows in the same stage of pregnancy do not seem to give the same amount of hormone per day. Further, a cow may give more hormone in the early stages of pregnancy than at a later time as indicated in the case of cow 71A, table I. More data on these and other points are being collected and will be presented at a future time.