Inhibition of free fatty acid release from isolated rat epididymal fat cells by some natural occurring organic acids.

The effects of some mono-, di- and tricarboxylic substrates (acetate, pyruvate, L-lactate, L-alanine, D,L-beta-hydroxybutyrate, succinate, D,L-malate, alpha-oxoglutarate, L-glutamate and citrate) on the basal lypolytic activity of isolated white adipocytes from fasted rats were investigated "in vitro". At concentrations ranging from 1 to 10 mM, the compounds tested, except lactate, had no influence on the rate of glycerol release but markedly reduced the free fatty acid (FFA) release. Lactate reduced both the glycerol and FFA release. As this "in vitro" lowering effect on FFA release was observed using concentrations occurring "in vivo" in the blood for lactate, beta-hydrobutyrate, and alanine, these results suggest that, besides lactate and beta-hydroxybutyrate, alanine may also assume an important role in the "in vivo" regulation of peripheral FFA mobilization and consequently of ketogenesis.