Changes in follicular estradiol-17 beta, progesterone and inhibin immunoactivity in healthy and atretic follicles during preovulatory maturation in the pig.
Follicular hormones, growth and granulosa cell gonadotropin sensitive adenylate cyclase activity were determined in healthy and atretic follicles during preovulatory maturation in pigs. Ovaries were recovered at slaughter which was 1, 3, 5 or 7 d after the last administration of a progesterone agonist (altrenogest). Plasma FSH decreased (P < .05) by 64% between days 1 and 3 and remained low through day 5. The number of large (> 5 mm) follicles increased from 2.7 on day 1 to 14.8 on day 3 and did not differ significantly among days 3, 5 and 7. The number of small (1-2 mm) and medium (3-5 mm) follicles decreased (P < or = .05) by 82% between days 3 and 5. Follicles first became estrogen-active (EA) (> or = 100 ng of estradiol-17 beta/ml of follicular fluid) on day 3, with 14.3% of medium and 73.8% of large follicles being EA. About 30% of small and 13% of medium follicles were morphologically atretic on days 1 and 3. However, by day 5, the proportion of atretic small and medium follicles had increased (P < or = .05) to 100 and 59%, respectively. Follicular fluid inhibin immunoactivity and estradiol-17 beta were lower (P < or = .05) and progesterone was greater (P < or = .05) in atretic than healthy follicles. Granulosa cells from large follicles produced (P < or = .05) more cAMP than cells from healthy or atretic small/medium follicles. Compared to control or pFSH treatment, pLH increased cAMP production by granulosa cells from large follicles on all days and from small/medium follicles on days 1 and 5; pLH had no effect on granulosa cells from atretic follicles. Compared to control, pFSH increased cAMP production in granulosa cells from healthy small/medium follicles only on day 1; no effect was detected in granulosa cells from large or atretic follicles on any day. We conclude that decreased secretion of FSH increased loss and atresia among non-ovulatory follicles. Atretic follicles were marked by loss of granulosa cell gonadotropin-sensitive adenylate cyclase activity and by low concentrations of estradiol-17 beta.
U.S. Department of Agriculture, Beltsville Agricultural Research Center, MD 20705.
H D
HD
Guthrie
D J
DJ
Bolt
B S
BS
Cooper
D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000097:blood; D004958:Estradiol / Q000096:biosynthesis* / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000502:physiology; D005496:Follicular Atresia / Q000378:metabolism; D015571:Follicular Fluid / Q000737:chemistry; D005498:Follicular Phase / Q000502:physiology; D006107:Granulosa Cells / Q000378:metabolism; D007265:Inhibins / Q000096:biosynthesis*; D007986:Luteinizing Hormone / Q000097:blood / Q000502:physiology; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011374:Progesterone / Q000096:biosynthesis*; D045167:Progesterone Congeners / Q000494:pharmacology; D013552:Swine / Q000502:physiology*; D013997:Time Factors; D014204:Trenbolone Acetate / Q000031:analogs & derivatives / Q000494:pharmacology
D045167:Progesterone Congeners; C023445:altrenogest; D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP; D014204:Trenbolone Acetate