Capillary blood flow in the endometrium and myometrium of conscious sheep: effect of catheterization of uterine arteries

Measures of capillary blood flow in the uterine tissues of conscious ewes were obtained by the use of microspheres. Total uterine capillary blood flow was significantly greater (P less than 0.01) at oestrus than at day 8 of the oestrous cycle [69.5 +/- (s.e.m.) 11.9, cf. 15.3 +/- 1.2 ml min-1, n = 7], reflecting increases of a similar order in both the endometrium and the myometrium. At these stages of the oestrous cycle, endometrial capillary blood flow constituted 83.6 and 80.5%, respectively, of the total uterine capillary flow. Following the placement of indwelling catheters in each middle uterine artery there was a decrease in the ratio of endometrial to myometrial capillary blood flow for 3-5 days.