title: Evidence for ovarian "inhibin": suppression of the secondary rise in serum follicle stimulating hormone levels in proestrous rats by injection of porcine follicular fluid.
abstract: The present studies were carried out to see if porcine follicular fluid could inhibit increases in serum follicle stimulating hormone (FSH) levels when injected into the rat. For these studies the pentobarbital-treated proestrous rat was chosen as the major test animal model. If an artificial surge of luteinizing hormone (LH) is administered to these rats, it can induce a synchronized secondary rise in FSH secretion rate. Normal saline-treated rats were also used as test animals. They exhibit preovulatory endogenous "surges" of LH and FSH, and also a secondary FSH rise. Porcine follicular fluid was harvested from medium-sized and large (3- to 10-mm diameter) follicles and treated with charcoal to remove endogenous steroids. Charcoal-treated porcine serum served as a control solution. The fluid was injected intraperitoneally in two 0.5-ml doses into pentobarbital-treated proestrous rats immediately and 3 hr after LH injection. Follicular fluid, but not the serum, suppressed the secondary, LH-induced FSH rise (P < 0.01) in a dose-dependent manner, without altering the effects of LH upon serum ovarian steroid levels or follicular rupture. It was effective down to a total dose of 200 mul. Porcine follicular fluid also blocked the secondary FSH surge in normal proestrous rats exhibiting endogenous LH/FSH primary surges. Thus, it would appear that porcine follicular fluid contains a non-steroidal substance(s) that can block the secretion of FSH that is secondary to a natural or artificial LH surge.
mesh_terms: D000818:Animals; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007986:Luteinizing Hormone / Q000494:pharmacology; D006080:Ovarian Follicle / Q000502:physiology*; D010424:Pentobarbital / Q000494:pharmacology*; D011247:Pregnancy; D011359:Proestrus; D011374:Progesterone / Q000097:blood; D051381:Rats; D013552:Swine
chemical_list: D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D010424:Pentobarbital
references.citation: J Endocrinol. 1976 Aug;70(2):301-6
references.pmid: 987150
references.citation: J Toxicol Environ Health. 1977 Sep;3(1-2):61-95
references.pmid: 336902
references.citation: Endocrinology. 1977 Jul;101(1):162-72
references.pmid: 558875
references.citation: Endocrinology. 1977 Jun;100(6):1550-6
references.pmid: 870306
references.citation: J Reprod Fertil. 1974 Mar;37(1):165-77
references.pmid: 4593604
references.citation: Biol Reprod. 1974 Mar;10(2):236-72
references.pmid: 4477965
references.citation: J Reprod Fertil. 1972 Oct;31(1):51-8
references.pmid: 4672940
references.citation: Nature. 1976 Sep 2;263(5572):71-2
references.pmid: 958466
references.citation: Biol Reprod. 1976 Jun;14(5):511-6
references.pmid: 1276315
references.citation: J Reprod Fertil. 1975 Jun;43(3):453-60
references.pmid: 1170326
references.citation: J Reprod Fertil. 1975 Aug;44(2):335-50
references.pmid: 1099197
references.citation: Endocrinology. 1973 Apr;92(4):1165-74
references.pmid: 4734433
references.citation: Recent Prog Horm Res. 1969;25:1-55
references.pmid: 4902948
references.citation: Recent Prog Horm Res. 1976;32:429-76
references.pmid: 785558
references.citation: Endocrinology. 1976 Jun;98(6):1460-5
references.pmid: 1278111
references.citation: Endocrinology. 1976 Apr;98(4):927-35
references.pmid: 945151
references.citation: Endocrinology. 1975 Sep;97(3):718-24
references.pmid: 1236790
references.citation: Nature. 1975 Oct 2;257(5525):402-4
references.pmid: 1178040
references.citation: Endocrinology. 1971 Mar;88(3):653-63
references.pmid: 5541302