Effect of lactate on FFA--release and cyclic 3', 5' AMP accumulation in fat cells at different pH.

Effect of lactate on FFA--release and cyclic 3', 5-AMP accumulation in fat cells at different pH. Acta Physiol. Pol., 1977, 28 (6): 505--510. The effect of sodium lactate on noradrenaline (NA), theophyline (Th), and dibutyryl cyclic 3', 5'AMP stimulated free fatty acid (FFA) release as well as on NA--stimulated cyclic 3', 5'AMP (cAMP) accumulation in isolated fat cells at different pH was studied. It was shown that at each of examined pH (6.8, 7.1, 7.4, 7.7) sodium lactate inhibits NA and Th-induced FFA release and NA-stimulated cAMP accumulation. It did not significantly change FFA release induced by dibutryl cyclic 3', 5'AMP. The inhibitory effect of sodium lactate both on FFA release and cAMP accumulation was markedly augmented at pH 7.1 and especially at pH 6.8 as compared to pH 7.4, while at pH 7.7 it remained essentially the same as at pH 7.4. The obtained results showed that lactate exerts its antilipolytic effect through the inhibitory action on cAMP accumulation and subsequently on the activity of the hormone-sensitive triglyceride lipase. An effect of lactate on FFA reesterification cannot be however excluded. It seems that the potentiation of the antilipolytic effect of lactate at pH below 7.4 has an important physiological significance. The mechanism protects effectively against an excessive, undesirable FFA-outflow from adipose tissue in situations in which FFA cannot be utilized.