BIOLOGICAL ASSAYS OF THE MALE CHICKEN PITUITARY FOR GONADOTROPIC POTENCY

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Abstract
Acetone-dried [male] chicken anterior pituitaries obtained from birds representing 5 different breeds and crosses were assayed for gonadotrophic potency, using the Levin-Tyndale mouse uterine unit (M.U.U.). This unit was of approx. the same order as a unit based upon the dosage resulting in a Stage 2 reaction of the vaginal epithelium of 50% of injected animals. The M.U.U. for the 5 types of unfractionated powders, from birds with testes ranging in weight from 10-25 gm., was equivalent to 0.3 mg. for a group of cross-breds, 0.4 mg. for Rhode Island Reds, White Leghorns and Columbians, and 0.5 mg. for Wyandottes. Tests for gonad-stimulating activity were also made on the immature [female] rat, and the plumage response of the African weaver finch was used for assays of the luteinizing factor. Approx. 10 mg. of powdered pituitary was found equivalent to a rat vaginal unit and 1 mg. of powder equivalent to a weaver finch unit. The findings place [male] chicken pituitary in the group of pituitary types with a relatively high luteinizing hormone content.