Effects of pyruvate and lactate on food intake in rat strains sensitive and resistant to dietary obesity.

We have investigated the effects of peripherally administered pyruvate and lactate on the intake of high fat (HF) and low fat (LF) diets by a strain of rat either sensitive (Osborne-Mendel, OM) or resistant (SSB/Pl) to high fat-induced obesity. Both pyruvate and lactate inhibited the intake of HF and LF diets by OM rats and these effects were blocked by selective hepatic vagotomy. In contrast, in S5B/Pl rats fed an LF diet the responses to pyruvate and lactate were attenuated and were absent in S5B/Pl rats fed the HF diet. These data suggest that OM and S5B/Pl rats differ either in their metabolism of pyruvate and lactate or in their responses to these metabolites.