The Effect of Lactate in Canine Subcutaneous Adipose Tissue in Situ1

Publisher Website
Google Scholar
Abstract
Fredholm, B. B.The effect of lactate in canine subcutaneous adipose tissue in situ. Acta physiol. scand. 1971.81. 110–123.Na‐L(+)‐lactate and Na‐pyruvate were administered by intraarterial infusion in canine subcutaneous adipose tissue, perfused with the dogs own blood either at a constant rate from a reservoir or by autoperfusion. The glucose uptake was found to be dependent upon the arterial glucose concentration. Similarly the uptake of lactate and pyruvate increased with increasing arterial concentrations, the latter more rapidly than the former. Infusion of Na‐L(+)‐lactate below 5 mM and Na‐D(—)‐lactate (10–11 mM) had no effect on the release of FFA and glycerol upon nerve stimulation (4 cps for 5 to 10 min). On the other hand Na‐L(+)‐lactate above 10 mM caused a 70 per cent inhibition of the release of FFA without significantly affecting the glycerol release. Na‐pyruvate (5 mM) decreased the glycerol output significantly, but increased the FFA release. Neither of the anions had any significant effect on the glucose uptake. Na‐lactate was not vasoactive, whereas Na‐pyruvate was slightly vasodilator.It is concluded that lactate in concentrations occurringa.g. during muscular exercise and shock is capable of significantly depressing the rate of FFA release upon nerve stimulation by increasing the rate of re‐esterification. The finding that lactate and pyruvate had opposite effects on esterification indicates a role of the cytoplasmatic NADH/NAD ratio in determining the rate of esterification.