Abstract
Practically all work dealing with the corpus luteum hormone, progestin, has been done with material derived from the pig, and most of the determinations of yield which give us information as to the amount of hormone in the raw material have been made on that species. A few investigators however have used corpora lutea of the cow and this source appears to be more convenient in some parts of the world. It may be of interest, therefore, to report the result of a brief study of the amounts of progestin found in cows' corpora lutea.
Three different collections of fresh cows' corpora lutea were made at different times: 2 from the local slaughter houses and one from the Wilson Laboratories of Chicago. In selecting the corpora lutea from the freshly slaughtered cattle, only the active glands of pregnant and non-pregnant cows were used, including the first stage in which the color is pale and stained with blood, and later stages marked by a cream color changing to bright yellow, and finally to reddish orange. Glands showing signs of retrogression, “corpora rubra,” identified as being bright red to brown in color, and toughened by the presence of much connective tissue, were all discarded. The material was minced and stored in 2 volumes of 95% alcohol, Allen having observed 1 that it may be so stored for at least 10 months with no loss of activity.
Alcoholic extracts were prepared following the procedures of Corner and Allen, 2 and standardized by their method, one rabbit unit being the minimum amount necessary to produce a +++ or ++++ progestational proliferation of the uterine mucosa of a freshly spayed adult female rabbit. The test is described in detail by Corner and Allen 2 and illustrated by Allen. 1
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