Effect of lactate on hepatic insulin clearance in perfused rat
liver.
Pagano, Claudio, Margherita Rizzato, Anna Maria Lombardi, Roberto
Fabris, Andrea Favaro, Giovanni Federspil, and Roberto Vettor.
Endocrine-Metabolic Laboratory, Institute of Semeiotica Medica,
University of Padova, via Ospedale 105, I-35100 Padova, Italy
APStracts 2:0340R, 1995.
The aim of our study was to investigate whether sodium lactate has any
effect on hepatic insulin dynamics in perfused rat liver. Rat livers
were perfused in situ with saline or increasing concentrations of
sodium lactate and hepatic insulin extraction was calculated from the
difference in insulin concentration between the portal and the
suprahepatic vein. Our results show that hepatic insulin extraction
at the three lactate concentrations added was higher than in the
control experiments (Lactate 1 mmol/l: 263 +/- 51 vs 765 +/- 114
[mu]UI x gr-1 x 30 min-1; p<0.005. Lactate 5 mmol/l: 341 +/- 80
vs 906 +/- 109 [mu]UI x gr-1 x 30 min-1; p<0.005. Lactate 15
mmol/l 438 +/- 21 vs 981 +/- 66 [mu]UI x gr-1 x 30 min-1;
p<0.005). No significant differences were observed in net
glucose balance across the liver during perfusion with lactate.
Moreover perfused liver displayed a net lactate production during
infusion with saline or lactate added at the lower concentrations (1
and 5 mM) while at the highest (15 mM) a net lactate uptake by the
liver was observed (p<0.05). Our results suggest that in
perfused rat liver, lactate may increase hepatic insulin clearance.
Thus energy fuels such as lactate and NEFA have opposite effects on
hepatic insulin clearance and may therefore contribute to the
regulation of posthepatic insulin delivery.
Received 28 September 1995; accepted in final form 28 November
1995
APS Manuscript Number R615-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 12 December 95