Capillary permeability of rabbit ovarian follicles prior to ovulation

Ultrastructurally, three possible pathways of capillary permeability were observed during the ovulatory process in rabbit ovarian follicles treated with human chorionic gonadotrophin: namely, pinocytotic vesicles, fenestrations, and interendothelial gaps. The increased permeability of perifollicular capillaries just prior to ovulation was confirmed as being primarily due to the formation of gaps, using carbon particles as a tracer.