Urinary Excretion of Estrogenic Compounds During Estrus and Gestation by the Bovine as Determined by Three Assay Methods

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Abstract
Small differences in magnitude and similiar trends of excretion of urinary estradiol 17 alpha and estradiol-17 beta were revealed when measured by fluorometry, spectrophotometry and by the mouse bioassay. When measuring urinary estrone the magnitude of the differences between measurements of the three methods was quite great. The quantities of urinary estrogenic substances excreted were low at 50 days of gestation with only a slight increase from then until 100 days of gestation. After 100 days of gestation the increase in the excretion rate became much more pronounced with a sharp increase occurring around 200 days. Most of this increase was due to larger quantities of urinary estradiol-17 alpha and estrone.