Uterine prostaglandin and blood flow responses to estradiol-17 beta in cyclic cattle.
Normal cyclic dairy cattle (n = 7) underwent a midventral laparotomy on day 17 of the estrous cycle and were fitted, ipsilateral to the CL, with: an electromagnetic flow transducer around the uterine artery (UA; n = 5); catheters within the ovarian vein (OV; n = 7) via a uterine branch of the ovarian vein, uterine branch of the ovarian artery (UBOA; n = 5) and facial artery (FA; n = 7). On day 18, blood samples were collected at 30 min intervals for 1 h prior to injection of estradiol-17 beta (E2; 3 mg) and 12 h post-E2. Uterine blood flow (UBF) was monitored continuously and plasma samples analyzed for PGF2 alpha and PGFM. Exact locations of catheters in reproductive tracts were verified post-slaughter. Data were analyzed by method of least squares analysis of variance. Uterine blood flow (ml/min) increased above pre-E2 flow rates within 30 min post-E2 injection, peaked between 2.5 to 3.5 h and declined between 4 to 8.5 h. A small secondary rise in UBF occurred between 9 and 12 h. Regression analysis for concentrations (pg/ml) of PGF2 alpha and PGFM in the OV (i.e., [OV]-[FA]) demonstrate a similar response as PGFM concentration in the FA in that all increased at approximately 3 h, peaked between 5 and 7 h and returned to near baseline levels by 9 to 10 h post-E2. Facial artery PGFM concentrations were positively correlated with uterine production of PGF2 alpha (r = .66) and PGFM (r = .30), whereas FA PGF2 alpha concentrations were not. In three of five cows, a difference in PGF2 alpha was detected between UBOA and FA (UBOA greater than FA); supportive of a local countercurrent exchange between the uterine venous drainage and the ovarian artery.
Knickerbocker
J J
JJ
Thatcher
W W
WW
Foster
D B
DB
Wolfenson
D
D
Bartol
F F
FF
Caton
D
D
D000818:Animals; D002417:Cattle / Q000502:physiology*; D015237:Dinoprost / Q000031:analogs & derivatives; D004958:Estradiol / Q000494:pharmacology*; D004971:Estrus; D005260:Female; D010053:Ovary / Q000098:blood supply; D011460:Prostaglandins F / Q000097:blood*; D012039:Regional Blood Flow / Q000187:drug effects; D013997:Time Factors; D014599:Uterus / Q000098:blood supply / Q000502:physiology*
D011460:Prostaglandins F; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D004958:Estradiol; D015237:Dinoprost