Possible involvement of nitric oxide in estrogen-induced uterine edema in the immature rat.
We examined whether nitric oxide mediates estrogen-induced uterine edema in the immature rat. Immature Wistar rats (19-21 days) received estradiol-17 beta (E2) in a single sc dose of 10 micrograms/animal and 6 h later the animals were sacrificed and the changes in uterine wet and dry weights were determined. E2 treatment caused a 93% increase in uterine wet weight (control, N = 6, 39.88 +/- 3.2 mg; E2 treated, N = 6, 76.8 +/- 4.9 mg), but not in dry weight, suggesting that it induces uterine edema. Pretreatment with L-nitroarginine methyl ester (L-NAME), a competitive antagonist of nitric oxide synthetase, at doses of 10 and 20 mg/kg, ip, caused a dose-related reduction (59 and 86%) in the uterine wet weight increase induced by E2. Furthermore, L-arginine (300-600 mg/kg, sc), the nitric oxide precursor, was able to reverse L-NAME (20 mg/kg)-induced decreases in uterine weight by 47 and 62%, respectively. The results suggest that nitric oxide is the principal mediator involved in estrogen-induced uterine edema in the immature rat.
Chaves
M C
MC
Departamento de Fisiologia e Farmacologia, Universidade Federal do Ceará, Fortaleza, Brasil.
Ribeiro
R A
RA
Rao
V S
VS
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004487:Edema / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D004958:Estradiol / Q000008:administration & dosage; D005260:Female; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D014591:Uterine Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D014599:Uterus / Q000187:drug effects
C053821:enkephalin-Leu, Ala(2)-Cys(6)-; D009569:Nitric Oxide; D004958:Estradiol; D016308:Enkephalin, Leucine-2-Alanine; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester