Follicular growth and regression during the 8 days after hypophysectomy in sheep

M. A. Driancourt, R. C. Fry, I. J. Clarke, L. P. Cahill

Research output: Contribution to journalArticleResearchpeer-review

32 Citations (Scopus)

Abstract

Ewes were hypophysectomized on Day 0 and ovareictomized 1, 2, 4 or 8 days later. There was no effect on hypophysectomy on the overall population of follicles > 0.8 mm in diameter during the time studied. However, the growth of healthy follicles > 2 mm in diameter was prevented by Day 2. Turnover of follicles was very active in the ovaries of hypophysectomized ewes as shown by peaks in the proportion of follicles in early atresia at Day 4 and in advanced atresia at Days 1 and 8. By Day 8, most of the measures of the population of follicles 0.8 to 2 mm in diameter were back to the values of Day 0 ewes. The mitotic index of the granulosa cells of the healthy follicles exhibited a similar pattern with a nadir at Day 2 followed by a return at Days 4 and 8 to values similar to Day 0 ewes. Ink-marked preovulatory follicles underwent a steady decrease in their histological size after hypophysectomy and this was associated with time-related changes in the health status of these follicles. By Day 1, 4 out of 7 follicles were still healthy while at Days 2, 4 and 8, all follicles were in advanced, late and collapsing atresia respectively. There was no evidence of an ability of PMSG (1000 i.u.) to rescue large follicles in advanced atresia (48 h after hypophysectomy). Furthermore, at 24 h after hypophysectomy , only 2 out of 5 follicles were maintained. However, PMSG partly overcame the depressing effects of hypophysectomy on the population of follicles 0.8 to 2 mm in diameter. It is concluded that (1) active follicular turnover can occur in the absence of gonadotrophins; (2) it takes about 8 days for a large follicle to disappear in the ovarian stroma; and (3) it is unlikely that rescue th atretic follicles massively contributes to the ovulatory response after PMSG.

Original languageEnglish
Pages (from-to)635-641
Number of pages7
JournalJournal of Reproduction and Fertility
Volume79
Issue number2
DOIs
Publication statusPublished - 1 Jan 1987
Externally publishedYes

Cite this

Driancourt, M. A. ; Fry, R. C. ; Clarke, I. J. ; Cahill, L. P. / Follicular growth and regression during the 8 days after hypophysectomy in sheep. In: Journal of Reproduction and Fertility. 1987 ; Vol. 79, No. 2. pp. 635-641.
@article{32a5ad51903d49a080dba4bf52e75df9,
title = "Follicular growth and regression during the 8 days after hypophysectomy in sheep",
abstract = "Ewes were hypophysectomized on Day 0 and ovareictomized 1, 2, 4 or 8 days later. There was no effect on hypophysectomy on the overall population of follicles > 0.8 mm in diameter during the time studied. However, the growth of healthy follicles > 2 mm in diameter was prevented by Day 2. Turnover of follicles was very active in the ovaries of hypophysectomized ewes as shown by peaks in the proportion of follicles in early atresia at Day 4 and in advanced atresia at Days 1 and 8. By Day 8, most of the measures of the population of follicles 0.8 to 2 mm in diameter were back to the values of Day 0 ewes. The mitotic index of the granulosa cells of the healthy follicles exhibited a similar pattern with a nadir at Day 2 followed by a return at Days 4 and 8 to values similar to Day 0 ewes. Ink-marked preovulatory follicles underwent a steady decrease in their histological size after hypophysectomy and this was associated with time-related changes in the health status of these follicles. By Day 1, 4 out of 7 follicles were still healthy while at Days 2, 4 and 8, all follicles were in advanced, late and collapsing atresia respectively. There was no evidence of an ability of PMSG (1000 i.u.) to rescue large follicles in advanced atresia (48 h after hypophysectomy). Furthermore, at 24 h after hypophysectomy , only 2 out of 5 follicles were maintained. However, PMSG partly overcame the depressing effects of hypophysectomy on the population of follicles 0.8 to 2 mm in diameter. It is concluded that (1) active follicular turnover can occur in the absence of gonadotrophins; (2) it takes about 8 days for a large follicle to disappear in the ovarian stroma; and (3) it is unlikely that rescue th atretic follicles massively contributes to the ovulatory response after PMSG.",
author = "Driancourt, {M. A.} and Fry, {R. C.} and Clarke, {I. J.} and Cahill, {L. P.}",
year = "1987",
month = "1",
day = "1",
doi = "10.1530/jrf.0.0790635",
language = "English",
volume = "79",
pages = "635--641",
journal = "Reproduction",
issn = "1470-1626",
publisher = "BioScientifica Ltd",
number = "2",

}

Follicular growth and regression during the 8 days after hypophysectomy in sheep. / Driancourt, M. A.; Fry, R. C.; Clarke, I. J.; Cahill, L. P.

In: Journal of Reproduction and Fertility, Vol. 79, No. 2, 01.01.1987, p. 635-641.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Follicular growth and regression during the 8 days after hypophysectomy in sheep

AU - Driancourt, M. A.

AU - Fry, R. C.

AU - Clarke, I. J.

AU - Cahill, L. P.

PY - 1987/1/1

Y1 - 1987/1/1

N2 - Ewes were hypophysectomized on Day 0 and ovareictomized 1, 2, 4 or 8 days later. There was no effect on hypophysectomy on the overall population of follicles > 0.8 mm in diameter during the time studied. However, the growth of healthy follicles > 2 mm in diameter was prevented by Day 2. Turnover of follicles was very active in the ovaries of hypophysectomized ewes as shown by peaks in the proportion of follicles in early atresia at Day 4 and in advanced atresia at Days 1 and 8. By Day 8, most of the measures of the population of follicles 0.8 to 2 mm in diameter were back to the values of Day 0 ewes. The mitotic index of the granulosa cells of the healthy follicles exhibited a similar pattern with a nadir at Day 2 followed by a return at Days 4 and 8 to values similar to Day 0 ewes. Ink-marked preovulatory follicles underwent a steady decrease in their histological size after hypophysectomy and this was associated with time-related changes in the health status of these follicles. By Day 1, 4 out of 7 follicles were still healthy while at Days 2, 4 and 8, all follicles were in advanced, late and collapsing atresia respectively. There was no evidence of an ability of PMSG (1000 i.u.) to rescue large follicles in advanced atresia (48 h after hypophysectomy). Furthermore, at 24 h after hypophysectomy , only 2 out of 5 follicles were maintained. However, PMSG partly overcame the depressing effects of hypophysectomy on the population of follicles 0.8 to 2 mm in diameter. It is concluded that (1) active follicular turnover can occur in the absence of gonadotrophins; (2) it takes about 8 days for a large follicle to disappear in the ovarian stroma; and (3) it is unlikely that rescue th atretic follicles massively contributes to the ovulatory response after PMSG.

AB - Ewes were hypophysectomized on Day 0 and ovareictomized 1, 2, 4 or 8 days later. There was no effect on hypophysectomy on the overall population of follicles > 0.8 mm in diameter during the time studied. However, the growth of healthy follicles > 2 mm in diameter was prevented by Day 2. Turnover of follicles was very active in the ovaries of hypophysectomized ewes as shown by peaks in the proportion of follicles in early atresia at Day 4 and in advanced atresia at Days 1 and 8. By Day 8, most of the measures of the population of follicles 0.8 to 2 mm in diameter were back to the values of Day 0 ewes. The mitotic index of the granulosa cells of the healthy follicles exhibited a similar pattern with a nadir at Day 2 followed by a return at Days 4 and 8 to values similar to Day 0 ewes. Ink-marked preovulatory follicles underwent a steady decrease in their histological size after hypophysectomy and this was associated with time-related changes in the health status of these follicles. By Day 1, 4 out of 7 follicles were still healthy while at Days 2, 4 and 8, all follicles were in advanced, late and collapsing atresia respectively. There was no evidence of an ability of PMSG (1000 i.u.) to rescue large follicles in advanced atresia (48 h after hypophysectomy). Furthermore, at 24 h after hypophysectomy , only 2 out of 5 follicles were maintained. However, PMSG partly overcame the depressing effects of hypophysectomy on the population of follicles 0.8 to 2 mm in diameter. It is concluded that (1) active follicular turnover can occur in the absence of gonadotrophins; (2) it takes about 8 days for a large follicle to disappear in the ovarian stroma; and (3) it is unlikely that rescue th atretic follicles massively contributes to the ovulatory response after PMSG.

UR - http://www.scopus.com/inward/record.url?scp=0023143371&partnerID=8YFLogxK

U2 - 10.1530/jrf.0.0790635

DO - 10.1530/jrf.0.0790635

M3 - Article

VL - 79

SP - 635

EP - 641

JO - Reproduction

JF - Reproduction

SN - 1470-1626

IS - 2

ER -