This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by SUZUKI, K. Articles by TAMAOKI, B.-I. Search for Related Content PubMed PubMed Citation Articles by SUZUKI, K. Articles by TAMAOKI, B.-I.

Effect of Pregnant Mare's Serum Gonadotrophin on the Activities of ⁴-5-Reductase, Aromatase, and Other Enzymes in the Ovaries of Immature Rats

KEIKO SUZUKI^*, KAZUHIKO KAWAKURA and BUN-ICHI TAMAOKI

National Institute of Radiological Sciences Anagawa-4-chome, Chiba-shi 280, Japan

Abstract

After incubation of progesterone, 17hydroxyprogesterone, androstenedione, and testostrone with an ovarian preparation (supernatant fluid at 10,000 x g) of immature rats (21–23 days of age) in the presence of NADPH, 3- and 3β-hydroxy-5-reduced steroids were obtained as the major metabolites. Among the enzyme activities relevant to the metabolism, ⁴-5reductase and 3β-hydroxysteroid dehydrogenase were intracellularly localized to the microsomal fraction (10,000-105,000 x g), and 3-hydroxysteroid dehydrogenase was detected exclusively in the cytosol fraction (supernatant fluid at 105,000 x g).

Within 2 days after a single injection of pregnant mare's serum gonadotrophin (10 IU/rat) to 21-day-old female rats, the following occurred: 1) an enhancement of 17-hydroxylase and C-17-C-20 lyase activities; 2) a suppression of ⁴-5-reductase activity; and 3) an increase in aromatizing activity. From the above-mentioned results, it was concluded that the increased secretion of estrogen from ovaries of immature rats stimulated by pregnant mare's serum gonadotrophin administration was caused by a modification of the ovarian enzyme activities relevant to estrogen production. (Endocrinology 102: 1595, 1978)

Footnotes

^* To whom requests for reprints should be addressed.

Visiting scientist from the National Institute of Animal Industry, Aoba-cho, Chiba-shi 280.

Received June 27, 1977.

This article has been cited by other articles:

				M Bengtsson and J Rydstrom Regulation of carcinogen metabolism in the rat ovary by the estrous cycle and gonadotropin Science, March 25, 1983; 219(4591): 1437 - 1438. [Abstract] [PDF]