Effects of Ergot Drugs on Prolactin and Growth Hormone Secretion, and on Mammary Nucleic Acid Content in C3H/Bi Mice2

Abstract

We investigated the effects of ergot alkaloids, ergocornine methanesulfonate and 2-Br-α-ergokryptine, on prolactin (PRL) and growth hormone (GH) secretion in C3H/Bi mice, a strain having a high incidence of spontaneous mammary tumors. Chronic administration of 0.2 mg/day of the 2 drugs for 20 days markedly depressed pituitary, serum, and urine PRL concentrations. The treatment had no appreciable effect on serum or urine GH, though the pituitary concentration of the hormone was slightly elevated. The weights of the pituitary glands, ovaries, uteri, and mammary glands were decreased, but adrenal weights remained unchanged. The RNA content of mammary tissue was reduced by 19–29% against 10–11% reduction in the mammary DNA content. The data suggest that the ergot alkaloids tested primarily depress PRL secretion which results in the inhibition of nucleic acid synthesis in the mammary gland, particularly RNA.

2

Supported by Public Health Service research grant CA 10425 from the National Cancer Institute, American Cancer Society grant P-571, and an award from the Kroc Foundation.

Author notes

3

Present address: Radioassay Systems Laboratories, Carson, Calif. 90746.

4

Division of Endocrinology, Scripps Clinic and Research Foundation, La Jolla, Calif. 92037.

5

We are indebted to Dr. E. Flückiger and Dr. K. Saameli of Sandoz Ltd., Basel, Switzerland, for providing us with ergocornine and CB-154.