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Human chorionic gonadotropin enhances the ability of gonadotropic hormones to stimulate aromatization in the testis of the rat



Human chorionic gonadotropin enhances the ability of gonadotropic hormones to stimulate aromatization in the testis of the rat



Endocrinology 109(6): 2004-2008



Four experiments examined estrogen (E) synthesis by the testis of rhe 12-day-old rat. Stimulation of aromatization was evaluated by using radioimmunoassay to measure the steroid content of methanolic homogenates of gonads which had been purified by Sephadex LH-20 chromatography. The 1st experiment evaluated the effects of hCG (1.0 IU/g BW [body wt]). A single injection of hCG approximately doubled the amount of E in the testes 6 h later (2.7 .+-. 0.6 to 5.0 .+-. 1.0 pg/2 testes). A 10-fold increase in the content of E in the testes was achieved after 3 days of twice daily treatment with hCG. Intermediate numbers of injections yielded intermediate responses. In a 2nd experiment, hCG (1.0 IU/g BW) and FSH (200 ng NIH-S13/g BW) were given in a combined single injection; a synergistic effect between the 2 gonadotropins was found (increase to 68 .+-. 6 pg E/2 testes), perhaps due to the increased availability of substrate. Combining the same dose of hCG with 1000 ng/g BW FSH gave additional stimulations of aromatization (147 .+-. 36 pg E/2 testes), but the synergistic effect was no longer detected. The 3rd experiment studied the effect of 3-day priming with hCG (1.0 IU/g BW, twice daily) on the subsequent response to FSH. Again, a synergistic effect was found, with the testes primed with hCG then stimulated with FSH having an E concentration of 1935 .+-. 231 pg/g or approximately 137 pg/2 testes. The 4th experiment showed that hCG priming did not sensitize the testes to the amount of LH activity which contaminated the FSH preparation, but did sensitize the testes to 1 .mu.g/g BW NIH-luteinizing hormone-S21. Evidently hCG induction of aromatizing enzymes increased during 3 days of treatment; hCG and FSH could synergize in stimulating testicular aromatization, and such synergism was demonstrated when combining acute or chronic hCG treatment with acute FSH stimulation.

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Accession: 000903630

Download citation: RISBibTeXText

PMID: 6796385

DOI: 10.1210/endo-109-6-2004



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