A Note on Four-Hour Excretion of Estrone and Estradiol-17β in the Urine of the Hen.

Abstract

Four-hour urinary excretions of estrone and of estradiol-17β by a hen were studied continuously for 37 days, during the latter part of which period the bird laid 8 eggs.Urine estrone and urine volume were pos tively correlated during the prelaying period but not during the subsequent laying period. The ratio estradiol-17β:estrone in the urine was significantly higher for prelaying days plus days of no ovulation than for days of ovulation.Four hour urinary estrone excretion for days of ovulation was significantly higher for the period 10-6 hour before ovulation than for other 4-hour periods. There were some indications of a second less prominent maximum of estrone excretion around the period 22-18 hour before ovulation. Similar but non-significant fluctuations were observed for 4-hour estradiol-17β excretion. Such maxima of steroid estrogen excretion were not observed on days of no ovulation during the prelaying period.