CHICK THYROID RESPONSES AS A BASIS FOR THYROTROPIC HORMONE ASSAY

Abstract

The effect of injected thyrotropic extract on the thyroid of day-old chicks was studied and compared with other methods of testing for this hormone. The chick thyroid was an exceedingly sensitive test for this material, reacting to 1/10 the amt. required to affect the wt. of guinea-pig thyroids. Chick thyroid response was consistent, significant values being obtainable with small groups. Crude non-pituitary extracts, urine and blood serum did not affect chick thyroid wt. Histological response was elicited by amts. of extract too small to produce hypertrophy. A statistical treatment of assay data was advocated.