title: Pulsatility and interrelationships of 13,14-dihydro-15-keto-PGF2alpha (PGFM), luteinizing hormone, progesterone, and estradiol in heifers.
abstract: Temporality among episodes of a prostaglandin F2alpha metabolite (PGFM), progesterone (P4), luteinizing hormone (LH), and estradiol (E2) were studied during preluteolysis and luteolysis. A vehicle group (n = 10) and a group with an E2-induced PGFM pulse (n = 10) were used. Blood sampling was done every 0.25 h for 8 h. An episode was identified by comparing its coefficient of variation (CV) with the intra-assay CV. Pulsatility of PGFM, P4, LH, and E2 in individual heifers was inferred if the autocorrelation functions were different (P < 0.05) from zero. About four nonrhythmic fluctuations of PGFM/8 h were superimposed on PGFM pulses. Pulsatility was detected for LH but not for P4 and E2. A transient increase in P4 was not detected during the ascending portion of a PGFM pulse. Progesterone decreased (P < 0.003) during Hours -1.25 to -0.50 of the PGFM pulse (Hour 0 = peak) and ceased to decrease temporally with an increase (P < 0.05) in LH. Maximum P4 concentration occurred 0.25 h after an LH pulse peak, and an increase (P < 0.005) in E2 began at the LH peak. Nadirs of LH pulses were greater (P < 0.05) and the nadir-to-nadir interval was shorter (P < 0.003) in the E2 group, which is consistent with reported characteristics during luteolysis. The results did not support the hypothesis of a transient P4 increase early in a PGFM pulse and indicated a balance between a luteolytic effect of PGF and a luteotropic effect of LH within the hours of a PGFM pulse.
authors.affiliation: Eutheria Foundation, Cross Plains, Wisconsin, USA. ginther@vetmed.wisc.edu
authors.forename: O J
authors.initials: OJ
authors.lastname: Ginther
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Fuenzalida
authors.forename: Minhaj A
authors.initials: MA
authors.lastname: Hannan
authors.forename: Mohd A
authors.initials: MA
authors.lastname: Beg
mesh_terms: D000818:Animals; D002417:Cattle; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000097:blood; D004958:Estradiol / Q000097:blood* / Q000493:pharmacokinetics / Q000494:pharmacology; D030762:Estrous Cycle / Q000097:blood*; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood*; D003341:Luteolysis / Q000097:blood; D010507:Periodicity; D011374:Progesterone / Q000097:blood*; D015203:Reproducibility of Results
chemical_list: C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D015237:Dinoprost