Changes in pituitary LHRH incorporation during the rat estrous cycle, and in rats made anovulatory by various experimental procedures

Abstract

Variations in anterior pituitary incorporation of LHRH in various experimental conditions have been investigated by administering tritiated LHRH. The pretreatment of animals with unlabelled LHRH significantly decreased the isotope incorporation in the pituitary gland. On the other hand, the incorporating capacity of the glands appeared to significantly change in relation to the different phases of the estrous cycle, the higher grade of radioactivity being detectable during the diestrous and proestrous phases. However, the amount of 3H-LHRH incorporated in the pituitary gland of rats bearing different types of constant estrous-anovulatory syndrome did not present significant variations in relation to the procedures employed in sterilization. Only rats neonatally androgenized with 1250 micrograms testosterone propionate showed a marked decrease of the incorporating capacity of the pituitary. One can conclude that the variations in pituitary responsiveness previously demonstrated among rats with the same anovulatory states are independent of LHRH incorporating capacity of the pituitary.