ADAPTATION OF THE SPIRAL ARTERY IN THE RABBIT OVARY TO CHANGES IN ORGANSIZE AFTER STIMULATION BY GONADOTROPHINS; EFFECT OF OVULATION AND LUTEINIZATION

Abstract

The ovarian artery gives rise to 1 or 2 spiral arteries in the hilus of the ovary. Each forms a helix of diminishing diam. lying along the length of the Ovary. The arterial supply to the stroma of the ovary is derived from the coils along the spiral vessels. In isolated [female] rabbits receiving gonadotrophic substances intravenously, a pattern of changes, or re-orientation, takes place during the period of rapid ovarian enlargement associated with generalized growth of Graafian follicles, ovulation, and luteinization. The features of adaptive alteration of the spiral vessels to increased size of the ovary consist of: (1) an increase in the distance between the coils of the spiral as this vessel is extended; (2) an extension of the loops so that by 48-72 hrs. after stimulation of the ovary with gonadotrophins the spiral arteries present a partially or completely undulating appearance; and (3) a lateral flattening of the coils of the spiral vessel. Except for the flattening which has been seen in ovaries taken as late as the 9th day of pseudopregnancy, the spiral configuration is largely restored by the 6th day, even though the ovary is still quite large.