FOLLICULAR PRESSURE AND DISTENSIBILITY IN OVULATION.

Micropipettes were introduced into follicles of exteriorized ovaries of rabbits anesthetized with pentobarbital. One pipette served for measurement of hydrostatic pressures, a second for the injection of small, measured amounts of saline. Impending ovulation did not measurably influence intrafollicular hydrostatic pressure. Artificial rupture could not be induced by increasing intrafollicular pressure by the injection of fluid. Tension-length diagrams for the elastic elements of the follicular wall, constructed from pressure measurements made following intrafollicular injections, indicate that a large increase in extensibility precedes rupture. Such a change in the physical characteristics of the follicle wall appears to be an essential part of the mechanism of ovulation.