This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rose, D. P. Articles by Mountjoy, K. G. Search for Related Content PubMed PubMed Citation Articles by Rose, D. P. Articles by Mountjoy, K. G.

Influence of Thyroidectomy and Prolactin Suppression on the Growth of N-Nitrosomethylurea-induced Rat Mammary Carcinomas¹

Division of Clinical Oncology, Wisconsin Clinical Cancer Center, University of Wisconsin, Madison, Wisconsin 53792

Mammary carcinomas were induced in female Sprague-Dawley rats with N-nitrosomethylurea. Thyroidectomy increased the serum prolactin and reduced serum growth hormone levels of 17 rats without affecting tumor growth. Pergolide mesylate, 80 µg twice daily for 7 days, suppressed the serum prolactin of another 17 animals; seven of 17 tumors continued to grow, four became static, and six (35%) underwent partial regression. Treatment with pergolide mesylate plus thyroidectomy reduced both serum prolactin and growth hormone in all of 14 rats, caused regression of ten of the 14 tumors (71%), while two became static, and two continued to grow. Five of the ten regressions were complete. Only the combined thyroidectomy-pergolide treatment group showed a significant difference in posttreatment surface area compared with the controls (p < 0.001). Ovine growth hormone, 40 µg/hr delivered by s.c. osmotic minipumps for 7 days, stimulated regrowth of six of seven tumors undergoing regression in response to thyroidectomy plus pergolide; the other one became static. Thyroxine, 2 µg/100 g body weight, stimulated regrowth of the tumors in another six thyroidectomized rats despite continued suppression of prolactin by pergolide. Thus, regression of N-nitrosomethylurea-induced mammary tumors produced by thyroidectomy plus pergolide is due to the combined suppression of circulating growth hormone and prolactin.

¹ Supported by USPHS Grant CA 14520 awarded to the Wisconsin Clinical Cancer Center by the National Cancer Institute, Grants CA 17579 and CA 20432, and an award from the Elsa U. Pardee Foundation.

² To whom requests for reprints should be addressed, at Division of Nutrition and Endocrinology, Naylor Dana Institute for Disease Prevention, American Health Foundation, Valhalla, N. Y. 10595.

Received 1/13/83. Accepted 3/ 7/83.

This article has been cited by other articles:

				E. D. Bischoff, R. A. Heyman, and W. W. Lamph Effect of the Retinoid X Receptor-Selective Ligand LGD1069 on Mammary Carcinoma After Tamoxifen Failure J Natl Cancer Inst, December 15, 1999; 91(24): 2118 - 2118. [Abstract] [Full Text] [PDF]