Effect of very high dose D-leucine6-gonadotropin-releasing hormone proethylamide on the hypothalamic-pituitary testicular axis in patients with prostatic cancer

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This study evaluated very high doses of a GnRH analog in rats and prostate cancer patients, finding that the treatment suppressed gonadotropin and testosterone levels to surgically castrate ranges.

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This study evaluated the effects of very high doses of a synthetic gonadotropin-releasing hormone analog on the hypothalamic-pituitary-testicular axis in both rats and men with stage D prostate cancer. In rodents, prolonged administration significantly suppressed reproductive organ weights and hormone levels in a dose-dependent manner, prompting a clinical trial in human patients. The results showed that daily doses of 1,000 or 10,000 micrograms transiently increased testosterone before reducing it to surgically castrate ranges, accompanied by profound suppression of luteinizing hormone to undetectable or prepubertal levels. These findings indicate that high-dose GnRH analog therapy effectively mimics surgical castration in men with prostatic cancer. Relevance to endometriosis: listed as one indication for GnRH antagonists, though the paper's main focus is uterine fibroids.

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Abstract

Potent synthetic analogs of gonadotropin-releasing hormone produce parodoxical antireproductive effects when administered chronically. These compounds are minimally toxic and may exhibit no plateau of the dose-response curve even at very high doses. These considerations served as the basis for our systematic evaluation of [D-leucine6-desarginine-glycine-NH2(10)]gonadotropin-releasing hormone (GnRH-A) proethylamide in the very high dose range (i.e., 10-fold larger amounts than previously used). In rats given the analog for 12 wk, prostate, testis, and seminal vesicle weights were suppressed to a greater extent with 200 micrograms q.d. than with 40 micrograms q.d. (P less than 0.01 prostate, less than 0.01 testis, less than 0.01 seminal vesicles), indicating dose-response effects in the very high dose range. 200 micrograms of [D-Leu6-des-Gly-NH2(10]-GnRH-A consistently suppressed leutinizing hormone (LH) values at 6 and 12 wk (basal 71 +/- 9.5; 6 wk 34 +/- 3.8; 12 wk 28 +/- 5 ng/ml) whereas 40 micrograms suppressed LH variably (basal 33 +/- 3.8; 6 wk 17 +/- 3.9; 12 wk 32 +/- 5.2). Testosterone fell to 15 +/- 2.4 and 19 +/- 2.0 ng/100 ml in response to 200 micrograms q.d. and to 27 +/- 6.4 and 22 +/- 7.4 ng/100 ml with the 40-micrograms dose. These findings in the rodent prompted treatment of stage D prostate cancer patients with similarly high doses of [D-Leu6-des-Gly-NH2(10)]-GnRH-A. After treatment for 11 wk with 1,000 or 10,000 micrograms/d of the analog, testosterone and dihydrotestosterone levels transiently rose and then fell into the surgically castrate range (testosterone 19 +/- 4.4 ng/100 ml [D-Leu6-des-Gly-NH2(10)]-GnRH-A vs. surgically castrate 11 +/- 0.9 ng/100 ml, P = NS; dihydrotestosterone 15 +/- 1.7 ng/100 ml GnRH-A vs. surgically castrate 15 +/- 4.1 ng/100 ml. P = NS). However, unlike the chronic stimulatory effect on the pituitary at lower doses, very high dose therapy resulted in profound suppression of plasma and urine LH. Plasma levels fell to the limit of assay detectability, whereas the more sensitive urinary assay detected prepubertal levels of excretion (i.e., 64 +/- 8.4 mlU/h). The highly sensitive rat interstitial cell testosterone bioassay for LH also demonstrated a marked decline in LH to undetectable levels in 17/19 subjects. Clinical results with [D-Leu6-des-Gly-NH2(10)]-GnRH-A simulate those achieved by surgical castration in men with prostatic cancer as suggested by available preliminary data.
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Advertisement Research Article Free access | 10.1172/JCI110940 Find articles by Warner, B. in: PubMed | Google Scholar Find articles by Worgul, T. in: PubMed | Google Scholar Find articles by Drago, J. in: PubMed | Google Scholar Find articles by Demers, L. in: PubMed | Google Scholar Find articles by Dufau, M. in: PubMed | Google Scholar Find articles by Max, D. in: PubMed | Google Scholar Find articles by Santen, R. in: PubMed | Google Scholar Published June 1, 1983 - More info Published in Volume 71, Issue 6 on June 1, 1983 J Clin Invest. 1983;71(6):1842–1853. https://doi.org/10.1172/JCI110940. © 1983 The American Society for Clinical Investigation J Clin Invest. 1983;71(6):1842–1853. https://doi.org/10.1172/JCI110940. © 1983 The American Society for Clinical Investigation Published June 1, 1983 - Version history - Abstract Potent synthetic analogs of gonadotropin-releasing hormone produce parodoxical antireproductive effects when administered chronically. These compounds are minimally toxic and may exhibit no plateau of the dose-response curve even at very high doses. These considerations served as the basis for our systematic evaluation of [D-leucine6-desarginine-glycine-NH2(10)]gonadotropin-releasing hormone (GnRH-A) proethylamide in the very high dose range (i.e., 10-fold larger amounts than previously used). In rats given the analog for 12 wk, prostate, testis, and seminal vesicle weights were suppressed to a greater extent with 200 micrograms q.d. than with 40 micrograms q.d. (P less than 0.01 prostate, less than 0.01 testis, less than 0.01 seminal vesicles), indicating dose-response effects in the very high dose range. 200 micrograms of [D-Leu6-des-Gly-NH2(10]-GnRH-A consistently suppressed leutinizing hormone (LH) values at 6 and 12 wk (basal 71 +/- 9.5; 6 wk 34 +/- 3.8; 12 wk 28 +/- 5 ng/ml) whereas 40 micrograms suppressed LH variably (basal 33 +/- 3.8; 6 wk 17 +/- 3.9; 12 wk 32 +/- 5.2). Testosterone fell to 15 +/- 2.4 and 19 +/- 2.0 ng/100 ml in response to 200 micrograms q.d. and to 27 +/- 6.4 and 22 +/- 7.4 ng/100 ml with the 40-micrograms dose. These findings in the rodent prompted treatment of stage D prostate cancer patients with similarly high doses of [D-Leu6-des-Gly-NH2(10)]-GnRH-A. After treatment for 11 wk with 1,000 or 10,000 micrograms/d of the analog, testosterone and dihydrotestosterone levels transiently rose and then fell into the surgically castrate range (testosterone 19 +/- 4.4 ng/100 ml [D-Leu6-des-Gly-NH2(10)]-GnRH-A vs. surgically castrate 11 +/- 0.9 ng/100 ml, P = NS; dihydrotestosterone 15 +/- 1.7 ng/100 ml GnRH-A vs. surgically castrate 15 +/- 4.1 ng/100 ml. P = NS). However, unlike the chronic stimulatory effect on the pituitary at lower doses, very high dose therapy resulted in profound suppression of plasma and urine LH. Plasma levels fell to the limit of assay detectability, whereas the more sensitive urinary assay detected prepubertal levels of excretion (i.e., 64 +/- 8.4 mlU/h). The highly sensitive rat interstitial cell testosterone bioassay for LH also demonstrated a marked decline in LH to undetectable levels in 17/19 subjects. Clinical results with [D-Leu6-des-Gly-NH2(10)]-GnRH-A simulate those achieved by surgical castration in men with prostatic cancer as suggested by available preliminary data. - Version history - Version 1 (June 1, 1983): No description Advertisement Advertisement Copyright © 2026 American Society for Clinical Investigation ISSN: 0021-9738 (print), 1558-8238 (online)

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MeSH descriptors

Adenocarcinoma Gonadotropin-Releasing Hormone Hypothalamo-Hypophyseal System Prostatic Neoplasms Testis Adenocarcinoma Adult Animals Castration Clinical Trials as Topic Dihydrotestosterone Dihydrotestosterone Dose-Response Relationship, Drug Follicle Stimulating Hormone Follicle Stimulating Hormone Gonadotropin-Releasing Hormone Gonadotropin-Releasing Hormone Gonadotropin-Releasing Hormone Humans Hypothalamo-Hypophyseal System

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