PGFM response to exogenous oxytocin and determination of the half-life of oxytocin in nonpregnant mares.
We investigated the half-life of oxytocin in reproductively normal mares and the prostaglandin response after oxytocin administrations. Mares were given oxytocin, 10 or 25 iu, i.v., on the day of, or 2 days after, ovulation, and frequent jugular blood samples were collected for analysis of oxytocin and Prostaglandin F metabolite (PGFM) by RIA. Neither dose of oxytocin nor day of treatment affected the half-life of the exogenous oxytocin, which was determined to be 6.8 min. A significant increase in PGFM was observed within 6 min of oxytocin administration and peak values were observed within 10 min. PGFM response after oxytocin administration on the day of ovulation appeared elevated compared to the response 2 days after ovulation.
Paccamonti
D L
DL
Department of Herd Health and Reproduction, University of Utrecht, The Netherlands.
Pycock
J F
JF
Taverne
M A
MA
Bevers
M
M
Van Der Weijden
G C
GC
Gutjahr
S
S
Schams
D
D
Blouin
D
D
D000818:Animals; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D006207:Half-Life; D006736:Horses / Q000097:blood / Q000378:metabolism*; D010121:Oxytocin / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology*; D011863:Radioimmunoassay / Q000662:veterinary; D011897:Random Allocation
C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D010121:Oxytocin; D015237:Dinoprost