Insulin signal decrease in muscle but not in the liver of castrated male rats from chronic exposure to fluoride

Abstract

With half the animals as controls without fluoride (F) in their drinking water, 16 of 32 seven-week-old castrated male Wistar rats were administered NaF in their drinking water and F contained in food pellets (estimated total F intake: 4.0 mg F/kg bw/day). After 42 days, determinations were made of the insulin receptor substrate (pp185–IRS-1/IRS/2), tyrosine phosphorylation status, and the extent of glycemia and insulinemia. This chronic treatment with F promoted: 1) decrease in the pp185 tyrosine phosphorylation status in the muscle tissue but not in the liver; 2) increase in the plasma F level; 3) no alteration in glycemia and insulinemia; 4) an increase in insulin resistance.