Gonadotropin-stimulated regulation of blood-follicle barrier is mediated by nitric oxide.
Although initially described over 30 years ago, the blood-follicle barrier has remained a biological enigma. In this study, we characterize the blood-follicle barrier with respect to its regulation of intrafollicular inter-alpha-trypsin inhibitor protein (I alpha I) influx after an ovulatory stimulus. We have found that I alpha I is localized within the ovarian vasculature but is excluded from the follicular compartment until an ovulatory stimulus is given. Within minutes after an ovulatory dose of human chorionic gonadotropin, I alpha I is localized within the follicular fluid of responding follicles where this protein becomes associated with and stabilizes the newly synthesized hyaluronic acid-rich cumulus extracellular matrix. Analysis of this process has shown that intravenous injection of sodium nitroprusside or excess substrate for nitric oxide synthase, L-arginine, mimics the effect of gonadotropic hormones on the influx of I alpha I into the follicular compartment of preovulatory follicles. Moreover, intravenous injection of specific nitric oxide synthase inhibitors, NG-nitro-L-arginine methyl ester and NG-nitro-L-arginine, inhibits gonadotropin-mediated intrafollicular influx of I alpha I and also inhibits ovulation in the mouse.
Powers
R W
RW
University of Cincinnati, College of Medicine, Ohio, USA.
Chen
L
L
Russell
P T
PT
Larsen
W J
WJ
D000510:Alpha-Globulins / Q000378:metabolism; D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D000818:Animals; D001808:Blood Vessels / Q000187:drug effects; D004730:Endothelium, Vascular / Q000201:enzymology; D005260:Female; D005498:Follicular Phase; D006062:Gonadotropins / Q000494:pharmacology*; D006207:Half-Life; D006728:Hormones / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019001:Nitric Oxide Synthase; D006080:Ovarian Follicle / Q000098:blood supply*; D010053:Ovary / Q000378:metabolism; D010060:Ovulation; D013997:Time Factors; D014361:Trypsin Inhibitors / Q000378:metabolism
D000510:Alpha-Globulins; D006062:Gonadotropins; D006728:Hormones; D014361:Trypsin Inhibitors; D009569:Nitric Oxide; C011877:inter-alpha-inhibitor; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases