DEPOSITION OF PIGMENT IN THE SPARROW′S BILL IN RESPONSE TO DIRECT APPLICATIONS AS A SPECIFIC AND QUANTITATIVE TEST FOR ANDROGEN11

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Abstract
Direct applications of as little as 0.063 [mu]g. of testosterone daily in alcoholic soln. to the bill of the castrated [male] English sparrow induced the unilateral deposition of a narrow band of pigment in the bill. When this androgen was administered systemically the deposition of pigment in the bill was bilateral and diffuse, and required a daily amt. of 8.0 [mu]g. for 10 days. The direct applications were made by allowing a drop of a soln. in absolute alc. to fall upon the skin-bill junction on one side. The pigmentation occurred at the point of application. The minimum effective total dose of testosterone so administered was 1.0 [mu]g. distributed in equal daily amis, over periods of 4, 8, or 16 days. Androsterone elicited an identical response, and its activity was the same as that of testosterone. Direct applications of progesterone and DCA in large amts. did not induce pigmentation of the bill. Adm. of 10.0 [mu]g. of estradiol benzoate daily simultaneously with testosterone did not modify the response of the bill to testosterone. Direct applications of an alcoholic soln. of crude extracts of testicular tissue from pigs and bulls induced a response identical with that evoked by testosterone and androsterone. The androgenic activity of the crude extracts was estimated on the basis of the amt. of each required for the production of pigmentation of the bill. Almost identical values were obtained when the same extracts were assayed in capons.