PROLACTIN RECEPTORS IN 7,12-DIMETHYLBENZ(A)ANTHRACENE-INDUCED MAMMARY-TUMORS FOLLOWING ENDOCRINE ABLATION

  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (11) , 3941-3943
Abstract
The effect of ovariectomy and hypophysectomy was determined on prolactin receptors in 7,12-dimethylbenz(a)anthracene-induced mammary tumors. Growing tumors from intact rats showed a wide range in the number of prolactin receptors. Ovariectomy caused a slight (.apprx. 30%) decrease in receptors regardless of whehter tumors regressed or continued to grow, while the affinity of the receptor for prolactin remained unchanged. Hypophysectomy, which caused a prompt 10-fold decrease in prolactin receptors in rat liver, caused only a slight reduction in prolactin receptors in tumors from these same animals. Autonomous and ovariectomy responsive 7,12-dimethylbenz(a)anthracene-induced mammary tumors probably cannot be distinguished on the basis of prolactin receptor sites and endocrine regulation of prolactin receptors were distinctly different in normal liver and neoplastic mammary tissue.