Modulation of water diffusion during gonadotropin-induced ovulation: NMR microscopy of the ovarian follicle.
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 stimulated-echo NMR microscopy experiments were applied here for studying modulations in water diffusion during gonadotropin-induced maturation of perfused rat ovarian follicles (32 degrees 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 microns, 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.
D000818:Animals; D001834:Body Water / Q000187:drug effects* / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D046508:Culture Techniques; D004058:Diffusion; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005260:Female; D015571:Follicular Fluid / Q000187:drug effects / Q000378:metabolism; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism; D007089:Image Enhancement; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008853:Microscopy; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D010060:Ovulation / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013799:Theca Cells / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
D006063:Chorionic Gonadotropin