Secretion of PGF2α and oxytocin during hyperthermia in cyclic and pregnant heifers

Autor: David Wolfenson, Matthew C. Lucy, William W. Thatcher, C.M. Barros, D.N. Marple, Thomas E. Spencer, K.A. Cummins, Frank F. Bartol, Dwight F. Wolfe, Lokenga Badinga
Rok vydání: 1993
Předmět:
Zdroj: Theriogenology. 39:1129-1141
ISSN: 0093-691X
DOI: 10.1016/0093-691x(93)90012-t
Popis: The effects of acute heat stress (HS) and oxytocin (OT) injection on plasma concentrations of PGF2alpha and OT were examined in cyclic (C; n = 15) and pregnant (P; n = 11) dairy heifers. On Day 17 of synchronized estrous cycles, animals were randomly assigned to either thermoneutral (TN; 20 degrees C, 20% RH) or HS (42 degrees C, 60% RH) chambers. The jugular vein of each heifer was cannulated and blood samples collected hourly for 4 h, then every 15 min for an additional 3 h. Oxytocin (100 IU) was injected (IV) 5 h after the start of blood collection. Plasma samples were assayed subsequently for concentrations of 13,14-dihydro-15-keto PGF2alpha (PGFM) and OT. During the 7-h experiment, body temperature of HS heifers reached 41.2 degrees C as compared to 38.5 degrees C in control heifers. Plasma concentrations of PGFM increased (P
Databáze: OpenAIRE