Translator Disclaimer
8 June 2011 Role of Luteinizing Hormone in Changes in Concentrations of Progesterone and Luteal Blood Flow During the Hours of a Simulated Pulse of 13,14-Dihydro-15-Keto-Prostaglandin F2alpha (PGFM) in Heifers
Author Affiliations +
Abstract

A bolus treatment (e.g., 25 mg) of prostaglandin F2alpha (PGF) in the study of luteolysis in cattle results in dubious interpretations. Therefore, in experiment 1 of the present study, a 13,14-dihydro-15-keto-PGF (PGFM) pulse was simulated by incremental intrauterine (IU) infusion of PGF for 2.7 h on Day 14 postovulation. Concentrations of PGFM during the first hour of infusion and at the maximum were not different between simulated (n = 7) and spontaneous (n = 7) pulses. In experiment 2, four groups (n = 6 per group) were treated at Minute 0 (beginning of infusion) as follows: saline (infused IU), PGF (infused IU), acyline/saline, and acyline/PGF. Two hours before Minute 0, each heifer was given flunixin meglumine to inhibit endogenous PGF secretion, and heifers in the acyline/saline and acyline/PGF groups were given acyline to inhibit luteinizing hormone (LH). Plasma progesterone concentrations were similar among groups during Minutes 0 to 60, with no indication of an initial transient progesterone increase in the two PGF groups. Progesterone began to decrease in the PGF groups at Minute 60 and to rebound at Minute 135 after the PGFM peak at Minute 120. The rebound was complete in association with an increase in LH in the PGF group, but it was not complete when LH was inhibited in the acyline/PGF group. Luteal blood flow increased during PGF infusion in the two PGF groups and remained elevated for approximately 2 h after the PGFM peak in the PGF group but not in the acyline/PGF group. Novel findings were that an initial transient increase in progesterone did not occur with the simulated PGFM pulse and that LH stimulated a progesterone rebound and maintained the elevated luteal blood flow after the PGFM peak.

An initial transient increase in progesterone does not occur during a simulated prostaglandin pulse; luteinizing hormone is involved in the progesterone rebound and the elevated luteal blood flow after the prostaglandin peak.

Hemanta K. Shrestha, Guilherme Pugliesi, Mohd A. Beg, and O.J. Ginther "Role of Luteinizing Hormone in Changes in Concentrations of Progesterone and Luteal Blood Flow During the Hours of a Simulated Pulse of 13,14-Dihydro-15-Keto-Prostaglandin F2alpha (PGFM) in Heifers," Biology of Reproduction 85(3), 482-489, (8 June 2011). https://doi.org/10.1095/biolreprod.111.092130
Received: 3 March 2011; Accepted: 1 June 2011; Published: 8 June 2011
JOURNAL ARTICLE
8 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top