Identification of a luteotrophic protein in bovine allantoic fluid.
Allantoic fluids (n = 65) of Day 24-37 bovine conceptuses were collected and assayed for luteotrophic activity in vitro with dispersed bovine luteal cells. Significant luteotrophic activity was found in 41% of the samples, with the highest percentage occurring between Days 25 and 28. The activity is ammonium sulphate-precipitable, heat-labile and inactivated by trypsin and chymotrypsin. Gel filtration column chromatography identified one peak of luteotrophic activity with a molecular weight of 68,000. Concanavalin A bound the luteotrophic activity, thus allowing rapid and substantial purification from a major protein of Mr 68,000 which was concanavalin A non-reactive. The results of one- and two-dimensional SDS-PAGE of concanavalin A-reactive fractions containing activity suggest that the luteotrophic activity present in allantoic fluid is associated with a glycoprotein of Mr 68,000 present in very low concentrations. The active factor does not appear to be alpha-fetoprotein. This protein may be an important conceptus-derived luteotrophin that stimulates progesterone production by the corpus luteum of cows during pregnancy.
Hickey
G J
GJ
Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
Walton
J S
JS
Hansel
W
W
D000481:Allantoin / Q000032:analysis*; D000818:Animals; D002417:Cattle; D003338:Corpus Luteum / Q000378:metabolism; D003340:Corpus Luteum Maintenance; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006065:Gonadotropins, Pituitary / Q000032:analysis*; D009479:Neuropeptides / Q000032:analysis*; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000302:isolation & purification*; D011374:Progesterone / Q000096:biosynthesis
D006065:Gonadotropins, Pituitary; D009479:Neuropeptides; D011257:Pregnancy Proteins; D000481:Allantoin; D011374:Progesterone