Capillary blood flow to ovarian follicles, stroma and corpora lutea of anaesthetized sheep.

The radioactive microsphere technique was used to determine the rate of blood flow through vessels of up to 15 mum diameter in the ovaries of 23 anaesthetized sheep in the 72 hr preceding ovulation. The validity of the microsphere technique was established in two preliminary studies. On Days 14, 15 and 16 of the cycle the rate of blood flow (ml.min-1 .100 g-1 tissue) was 1122, 708 and 116 to the CL; 157, 258 and 140 to the stroma; and 627, 742 and 1096 to the follicles, respectively. Blood flow to grossly atretic follicles did not differ significantly from that to non-atretic follicles of an equivalent size. Change in blood flow do not appear to initiate or control the activation, steriodogenic function or atresia of follicles.