Diminished levels of prostaglandin E in type I diabetic oocyte-cumulus complexes. Influence of nitric oxide and superoxide dismutase.
In the present work the prostaglandin E (PGE) production by ovulated, immature and in vitro matured oocyte-cumulus complexes (OCC) was evaluated in a rat model of type I diabetes induced by streptozotocin (60 mg kg(-1)). A diminished number of ovulated OCC were found in the type I diabetic rat. In contrast to the increment in PGE generation found previously in OCC and embryos from type II diabetic rats, it was found that PGE production by type I diabetic OCC was diminished in comparison with the controls. Nitric oxide synthase (NOS) activity is enhanced in proestrous ovaries from type I diabetic rats, but cGMP levels are diminished. SIN-1 (300 microM), a nitric oxide donor, significantly enhanced PGE generation by control OCC, but was unable to modify the PGE levels in type I diabetic OCC. L-NMMA, a nitric oxide inhibitor that diminished PGE values in type II diabetic OCC, did not modify PGE generation in either control and type I diabetic OCC. Superoxide dismutase (SOD, 1000 U mL(-1)), and SOD (1000 U mL(-1)) plus SIN-1 (300 microM), enhanced PGE generation by both control and diabetic OCC. The present results suggest that even when nitric oxide (NO) is overproduced in diabetic ovaries, the NO-PGE pathway is impaired in type I diabetic OCC. As SOD additions are able to increase PGE generation by diabetic OCC, high concentrations of free oxygen radicals might be quenching the NO, impairing its physiological functions.
Jawerbaum
A
A
Centro de Estudios Farmacológicos y Botánicos, Consejo Nacional de Investigaciones Cientificas y Técnicas, Buenos Aires, Argentina. A.JAWERBAUM@ABACONET.COM.AR
Gonzalez
E T
ET
Carolina
P
P
Debora
S
S
Christian
P
P
Gimeno
M A
MA
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D005260:Female; D009569:Nitric Oxide / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000378:metabolism*; D011458:Prostaglandins E / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000494:pharmacology*
D011458:Prostaglandins E; D009569:Nitric Oxide; D013482:Superoxide Dismutase