Altered prostanoid production by cumulus-oocyte complexes in a rat model of non-insulin-dependent diabetes mellitus

Ovulation, oocyte maturation and PGE and PGF_2α production by oocyte-cumulus complexes were evaluated in rats with non-insulin-dependent diabetes induced by neonatal streptozotocin. Diabetic rats had normal estrous cycles, but ovulated a lower number of oocytes at estrus. When oocytes from control and diabetic rats obtained at proestrus were matured “in vitro” during 1, 2 or 4 hours (hr) of culture, differences were not found in the percent of germinal vesicle breakdown between both experimental groups. PGE and PGF_2α accumulation was higher in ovulated oocyte-cumulus complexes when compared to immature or “in vitro”-matured oocyte-cumulus complexes in both normal and diabetic rats. When control and diabetic rats are compared, more PGE and PGF_2α accumulation was observed in immature, “in vitro”-matured and in ovulated oocytecumulus complexes.

A lower number of oocytes ovulated and increased oocyte-cumulus complexes prostaglandin production has been observed in this mildly diabetic experimental model. These abnormalities are similar to those previously found when 10 day embryos were evaluated in noninsulin-dependent diabetic rats.