INHIBITION OF PITUITARY HORMONE ACTIVITY WITH DERIVATIVES OF PITUITARY PREPARATIONS1

Abstract

Pituitary preparations with thyrotropic (TSH) and gotiadotropic activity have been acetylated with acetic anhydride. Under all reaction conditions tested, acetylation destroyed the ability of these preparations to increase chick thyroid weight and uptake of radioactive I. The destruction of gonadotropic activity by acetylation was dependent on the temperature and the duration of the reaction. In some cases, these acetylated pituitary preparations were able to offset the increase in thyroid weight and uptake of radioactive I produced by an unmodified pituitary preparation. There was no alteration in the gonadotropic response of chicks treated with a gonadotropic preparation and the acetylated pituitary preparation. Analysis of the acetylated pituitary preparation revealed complete blocking of the free amino groups with the addition of an appropriate number of volatile acid groups.