Modulation of water diffusion during gonadotropin‐induced ovulation: nmr microscopy of the ovarian follicle

Publisher Website
Google Scholar
Abstract
The preovulatory rat follicle reaches a diameter of 1 mm with no internal blood vessels. Nutrient supply to the enclosed oocyte depends solely on passive diffusion across the follicular wall and the follicular fluid. Spin‐echo and stimulatedecho NMR microscopy experiments were applied here for studying modulations in water diffusion during gonadotropin‐induced maturation of perfused rat ovarian follicles (32°C). Two diffusion compartments were observed for the follicular wall. The intracellular water diffusion coefficient, measured at a short diffusion time (9 ms) was 0.28 x 10−5 cm2/s. Diffusion at long diffusion times was restricted to 16 μm, the size of cells in the follicular wall, and did not change during maturation. In the follicular fluid a transient 26% decrease in the diffusion coefficient was observed 4–7 h after gonadotropin stimulation, a change that is bound to affect the metabolic balance of the oocyte before ovulation.