Effects of prolactin or growth hormone on growth of carcinogen-induced mammary tumors of adreno-ovariectomized rats

✍ Scribed by Hiroshi Nagasawa; Reiko Yanai

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: French
• Weight: 600 KB
• Volume: 6
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910060320

✦ Synopsis

Abstract

The effects of exogenous administration of bovine prolactin and bovine growth hormone (GH) on 7,12‐dimethylbenz(a)anthracene (DMBA)‐induced mammary tumor were investigated in female Sprague‐Dawley rats. Rats were bilaterally adrenoovariectomized 15 days after the appearance of the first palpable mammary tumors and were treated with either prolactin or GH beginning the next morning. Marked stimulation of incidence and growth of mammary tumor and of normal mammary gland growth followed subcutaneous injections of 1.25 or 2.5 mg prolactin twice daily for 20 days. GH had no effects on mammary tumor, whereas it accelerated the growth of normal mammary gland and increased the body weight. The administration of 2.5 mg prolactin twice daily for 10 days, beginning 20 days after adreno‐ovariectomy, raised the number and size of regressed mammary tumors to the pre‐operative levels, while the half dose of prolactin had no effects.

These results indicate that prolactin is the principal hormone responsible for the growth of DMBA‐induced mammary tumor of the rat, whereas GH has only a minimal role in the growth of the tumor.