Effects of FSH and LH on incorporation of [3H]thymidine into follicular DNA

S. K. Roy, G. S. Greenwald

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

To assess the roles of FSH and LH on follicular growth, after various experimental manipulations, hamster follicles were sorted into 10 stages and incubated for 4 h with [3H]thymidine. Stages 1-4 correspond to follicles with 1-4 layers of granulosa cells, respectively; Stage 5 = 5 or 6 layers of granulosa cells plus theca; Stage 6 = 7-8 layers of granulosa cells plus theca; Stage 7 = early formation of the antrum; Stages 8-10 = small, intermediate and large antral follicles, respectively. Phenobarbitone sodium injected at 13:00 h on pro-oestrus blocked the normal rise of blood FSH and LH concentrations at 15:00 h and prevented the increase of [3H]thymidine incorporation into follicles of Stages 1-9. The optimal treatment to reverse the effects of phenobarbitone was 1 μg FSH and 2 μg LH injected i.p. at 13:00 h which restored DNA replication to follicles of Stages 2-10: FSH acted primarily on Stages 2-5 and LH on Stages 5-10. Injection of phenobarbitone at 13:00 h on pro-oestrus followed by 2.5 μg FSH at 22:00 h restored DNA synthesis by the next morning to follicles at Stages 1-8. In hamsters hypophysectomized at 09:00 h on the day of oestrus (Day 1), injection on Day 4 of 2.5 μg FSH restored DNA synthesis 6 h later to Stage 2-6 follicles. Unilateral ovariectomy on Day 3 resulted 6 h later in an acute rise in FSH and LH and change of follicles from Stage 4 to Stage 5 but, paradoxically, there was decreased synthesis of DNA in follicles of Stages 5-10. The incorporation of [3H]thymidine was at normal low levels for Stage 5-10 follicles by 24 h after unilateral ovariectomy with significant increases in follicles of Stages 1-4. We conclude that small preantral follicles are already dependent on FSH for DNA synthesis and LH action is manifested when the follicles acquire a theca (Stage 5 onwards) and when LH receptors appear in granulosa cells.

Original languageEnglish (US)
Pages (from-to)201-209
Number of pages9
JournalJournal of reproduction and fertility
Volume78
Issue number1
DOIs
StatePublished - 1986
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Embryology
  • Molecular Biology
  • Obstetrics and Gynecology
  • Developmental Biology

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