Serum Prolactin Levels of Rats Under Continuous Estrogen Stimulation and 2 Br-α-Ergocryptine (CB-154) Injection 1

Abstract

Summary

The ability of 2 Br-α-ergocryptine (CB-154) to suppress serum prolactin levels was examined in animals under the influence of continuous estrogen stimulation. A single injection of polyestradiol phosphate (Estradurin) once every 21 days produced a constant elevation of serum prolactin. The simultaneous administration of 1 mg/day of CB-154 to estrogenized animals suppressed serum prolactin levels below that of Estradurin alone but the levels were significantly greater than those of animals receiving CB-154 alone. It was suggested that, while CB-154 prevents the release of prolactin, estrogen stimulates prolactin synthesis despite the block of its release. Ether anesthesia may be capable of partially overriding the block of CB-154 and released the stored hormone from the gland.

The authors thank Mrs. Cynthia Van De Walle for her skilled and dedicated technical assistance in the performance of the prolactin radioimmunoassay. We also acknowledge the Rat Pituitary Hormone Distribution Program of the NIAMDD for the rat prolactin used for iodination (RP-1-1) and standards (RP-1). The authors thank Dr. J. H. Trapold of Sandoz Pharmaceuticals, East Hanover, NJ, for the gift of 2 Br-α-ergocryptine (CB-154) used in this study.