Co-ordinate actions of FSH and insulin-like growth factor-I on LH receptor expression in rat granulosa cells

M. Kanzaki, M. A. Hattori, R. Horiuchi, I. Kojima

研究成果: Article査読

20 被引用数 (Scopus)

抄録

The actions of FSH and Insulin-like growth factor-I (IGF-I) were studied in cultured rat ovarian granulosa cells. Cells became differentiated and expressed LH receptors when they were incubated for 72 h with 200 μg FSH/l (high FSH) but not 20 μg FSH/l (low FSH). Treatment with high but not low FSH increased the release of both immunoreactive and bioactive IGF-I into the medium. A combination of low FSH and IGF-I reproduced the effect of high FSH on LH receptor expression. We then examined the critical time when low FSH and IGF-I exerted their effects. In the presence of continuous low FSH, IGF- I was capable of inducing LH receptor expression even when added 24 h after the addition of low FSH. However, when IGF-I was added at 36 h, LH receptor expression measured at 72 h was greatly reduced. In contrast to the action of IGF-I, continuous exposure to low FSH was required for LH receptor expression, and IGF-I had no effect when FSH was not included for the entire 72 h of culture. DNA synthesis as assessed by both [3H]thymidine incorporation and nuclear bromodeoxyuridine labelling was moderate at the beginning of culture and markedly reduced at 24 h both in the presence and absence of either high FSH or low FSH plus IGF-I. In the presence of either high FSH or a combination of low FSH plus IGF-I, DNA synthesis remained decreased for up to 72 h whereas it began to increase in the absence of either high FSH or a combination of low FSH plus IGF-I. A similar increase in DNA synthesis was observed after 48 h when granulosa cells were treated with low FSH alone, which did not induce LH receptor expression. These results indicate that 1) growth and differentiation of granulosa cells are regulated inversely; 2) FSH and IGF-I act together to induce LH receptor expression; and 3) action of IGF-I is dependent on the presence of FSH.

本文言語English
ページ(範囲)301-308
ページ数8
ジャーナルJournal of Endocrinology
141
2
DOI
出版ステータスPublished - 1994
外部発表はい

ASJC Scopus subject areas

  • 内分泌学、糖尿病および代謝内科学
  • 内分泌学

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