Chemical Estimation of Progesterone in the Blood of Cattle, Sheep, and Goats

During the course of studies on the hormonal control of mammary gland growth, there arose a need for estimations of the progesterone secretion rate. This was true especially in the larger domesticated animals, in which urinary metabolites of the hormone have received little attention (4). Furthermore, the significance of pregnandiol determinations is at least uncertain in species in which it is excreted Estimation of the progesterone secretion rate by replacement therapy in pregnant cattle, after ablation of the corpus luteum, provides another technique of indirect measurement However, by this technique placental progesterone secretion is not determined. Within recent years more direct methods have been sought. Hooker and Forbes Partition chromatography. The system employed (petroleum ether--80% aqueous methanol) was that described by Bush (2) for the paper chromatography of steroids. A chromatographic chamber in the form of a cylindrical glass jar, 6 18 in., was immersed in a larger glass cylinder, 12 18 in., which served as a water bath. By means of a heating element, thermometer, thermoregulator,-"