Relationship of 15-keto-13,14-dihydro-prostaglandin F2 alpha concentrations in peripheral plasma with local uterine production of F series prostaglandins and changes in uterine blood flow during the early postpartum period of cattle.

Cows were prepared for surgery, either within 12 h after parturition (Day 0, n = 3), on Day 1 (n = 1) or on Day 2 (n = 1) postpartum. The previously gravid uterine horn was exposed through a high lumbar laparotomy, and catheters inserted into an uterine branch of the ovarian vein (UBOV) and in the main uterine artery (UA) via a branch of the main uterine artery. A blood flow transducer (8-13 mm, internal diameter) was placed around the UA. Starting 12-24 h following surgery, simultaneous blood samples were collected from UBOV and UA at 15-min intervals for 1 or 2 h daily from Days 1 to 10 postpartum (mean = 5.3 days). Concurrently, uterine blood flow (UBF) was recorded daily for 6 h. Mean concentrations of prostaglandin F2 alpha (PGF2 alpha) and 15-keto-13, 14-dihydro-PGF2 alpha (PGFM) were higher (P less than 0.01) in UBOV than UA (4.64 +/- 0.6, n = 96 vs. 0.08 +/- 0.02 ng/ml, n = 92 and 5.67 +/- 0.41, n = 98 vs. 1.02 +/- 0.09, n = 94, ng/ml, respectively). Concentrations of PGF2 alpha and PGFM in the UBOV increased (P less than 0.1) on Days 2 and 3 and decreased (P less than 0.01) thereafter. Mean UBF (ml/min) decreased (P less than 0.01) from 3079 +/- 683 on Day 1 to 602 +/- 56 on Day 2 and was 413 +/- 55 on Day 5.(ABSTRACT TRUNCATED AT 250 WORDS)