title: Changes and interrelationships among luteal LH receptors, adenylate cyclase activity and phosphodiesterase activity during the bovine estrous cycle.
abstract: Changes and interrelationships among the cellular mechanisms that may regulate luteal progesterone synthesis during the bovine estrous cycle were studied. Corpora lutea (CL) were enucleated from 30 cows via a transvaginal incision on d 4, 7, 10, 13, 16 and 19 following estrus (estrus = d 0). Mean corpus luteum weight, and luteal progesterone and plasma progesterone concentrations increased (P less than .05) from d 4 to 7 or 10, and declined following luteal regression (d 19). Unoccupied LH receptor (UOR) concentrations increased (P less than .05) more than fourfold from d 4 (38 fmol/mg protein) to d 16 (173 fmol/mg protein) before declining (P less than .05) by d 19 (30 fmol/mg protein). The dissociation constant for UOR concentrations increased (P less than .05) during the estrous cycle. Concentrations of occupied LH receptors (OR) were less (P less than .05) on d 7 than other days; however, the total number of OR/CL increased fourfold from d 4 (47 fmol/CL) to d 10 (221 fmol/CL) and remained similar thereafter. Basal adenylate cyclase, LH-activated adenylate cyclase, and Gpp(NH)p-activated adenylate cyclase activities were greatest (P less than .05) on d 7 to 16 as compared with d 4 and 19. Luteinizing hormone stimulated (P less than .05) adenylate cyclase activity relative to basal activity on d 7, 10, 13, and 16; whereas, Gpp(NH)p stimulated (P less than .05) adenylate cyclase activity relative to basal activity at each period. Phosphodiesterase was 46% greater on d 19 as compared with d 4.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.forename: H A
authors.initials: HA
authors.lastname: Garverick
authors.forename: M F
authors.initials: MF
authors.lastname: Smith
authors.forename: R G
authors.initials: RG
authors.lastname: Elmore
authors.forename: G L
authors.initials: GL
authors.lastname: Morehouse
authors.forename: L S
authors.initials: LS
authors.lastname: Agudo
authors.forename: W L
authors.initials: WL
authors.lastname: Zahler
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002417:Cattle / Q000502:physiology*; D003338:Corpus Luteum / Q000378:metabolism*; D004971:Estrus; D005260:Female; D003341:Luteolysis; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011974:Receptors, LH
chemical_list: D011956:Receptors, Cell Surface; D011974:Receptors, LH; D011374:Progesterone; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases