Porcine ovarian inhibin preparations sensitize cultured ovine gonadotrophs to luteinizing hormone-releasing hormone.
Treatment of ovine pituitary cell cultures with an acetone powder of porcine follicular fluid (APPFF; 50 micrograms/ml) decreased FSH secretion 60%, did not alter basal LH secretion, but increased by 2- to 3-fold the effectiveness of LHRH or D-Lys6-LHRH (10(-8) M) in releasing LH. Chromatography of APPFF on Matrex Gel Red A (MGRA) yielded a protein fraction (MGRA-IV) in which both FSH-inhibiting and LHRH-enhancing activities were enriched 8-fold. Both activities were destroyed by trypsin, but both were highly resistant to heat. The apparent mol wt of the active substance(s) was greater than 10,000. The LHRH-enhancing effect of MGRA-IV was reversible and declined, with an apparent half-life of 7 h, when MGRA-IV treatment was discontinued. There was too little estrogen in either APPFF or MGRA-IV to account for any of the activities. These results demonstrate that porcine follicular fluid contains LHRH-enhancing activity along with classical inhibin activity and that both activities may be linked in one molecule. These dual activities may be important in a number of species.
D000818:Animals; D001491:Basophils / Q000502:physiology*; D002478:Cells, Cultured; D002850:Chromatography, Gel / Q000379:methods; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D007265:Inhibins / Q000378:metabolism / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism; D006080:Ovarian Follicle / Q000032:analysis; D010053:Ovary / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000502:physiology*; D012756:Sheep; D013552:Swine; D014020:Tissue Extracts / Q000494:pharmacology
D014020:Tissue Extracts; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone