Abstract
A gonadoliberin analog, (d-leucyl6, desglycyl-NH210, prolyl ethylamide9) gonadoliberin, is known to suppress ovarian function and plasma prolactin levels. Its antitumor activity was evaluated against mammary tumors induced in Sprague-Dawley rats by dimethylbenz(a)anthracene. Observations were made when the analog, referred to as A-43818, was given alone and together with estrogen replacement or perphenazine. A-43818, 10 µg s.c. twice a day for 6 weeks, was highly effective in producing tumor remissions. All of the 11 animals survived throughout the observation period, complete regressions occurred in 8 of 13 tumors, and 2 were classified as static. None of the 16 tumors in 12 control rats regressed, and there were 4 deaths. When estradiol benzoate, 2 µg s.c. each day, was administered with the A-43818, antitumor activity was suppressed; only 2 of 17 tumors regressed, 6 were static, and 5 of the 10 rats in this group died. Perphenazine, 1 mg i.m. daily, a dose known to cause hyperprolactinemia, also impaired the efficacy of A-43818. Three of 14 tumors regressed, 6 were static, and the rest continued to grow; 3 of the 12 rats died within 6 weeks of starting treatment.
Footnotes
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↵1 Supported in part by USPHS Grant CA 14520 awarded to the Wisconsin Clinical Cancer Center by the National Cancer Institute.
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↵2 To whom requests for reprints should be addressed.
- Received April 16, 1979.
- Accepted July 10, 1979.
- ©1979 American Association for Cancer Research.
Volume 39, Issue 10
