RESUMO
Effects of lead (Pb) and cadmium (Cd) both alone or in combination on the binding of LH and FSH on isolated granulosa cells were studied. Granulosa cells isolated from proestrous rats were incubated (in vitro) with lead acetate and/or cadmium acetate (0.03 microM of Pb or Cd) for 1 hr. LH binding was dropped to 84% in Pb treated cells, 72.5% in Cd treated cells and 74.8% in combined metal treated cells compared to control. FSH binding dropped to 85.5% in Pb treated cells, 71.16% in Cd treated cells and 72.5% in combined metal treated cells compared to control. Activity of 17beta Hydroxy Steroid Dehydrogenase (17betaHSDH), a key steroidogenic enzyme was reduced by 52% in Cd and 37% in combined metal exposed cells whereas Pb exposed cells showed 31% reduction in the enzyme activity. Pretreatment with SH groups protectants (glutathione [GSH], dithiothretol [DTT]) and zinc caused an ameriolation in enzyme activity whereas Zn pretreatment showed an increase in gonadotropin binding in metal exposed cells. These results suggest that both Pb and Cd can cause a reduction in LH and FSH binding, which significantly alters steroid production in vitro and exerts a direct influence on granulosa cell function.