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Updated: May 22, 2026
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Published on: July 25, 2025
Blood flow in endogenous and transplanted pancreatic islets in anesthetized rats: effects of lactate and pyruvate
Andreea Barbu1, Åsa Johansson, Birgitta Bodin
1Departments of Medical Cell Biology, Uppsala University, Uppsala, Sweden. andreea.barbu@medsci.uu.se
Objective:
The objective of this study was to evaluate the effects of exogenously administered lactate and pyruvate on blood perfusion in endogenous and transplanted islets.
Methods:
Anesthetized Wistar-Furth rats were given lactate or pyruvate intravenously, and regional blood perfusion was studied 3 or 30 minutes later with a microsphere technique. Separate rats received a 30-minute infusion of pyruvate or lactate into the portal vein before blood flow measurements. We also administered these substances to islet-implanted rats 4 weeks after transplantation and measured graft blood flow with laser Doppler flowmetry. The expression of monocarboxylate transporter 1 and lactate dehydrogenase A was analyzed.
Results:
The expression of monocarboxylate transporter 1 and lactate dehydrogenase A was markedly up-regulated in transplanted as compared with endogenous islets. Administration of pyruvate, but not lactate, increased mesenteric blood flow after 3 minutes. Pyruvate decreased mesenteric blood flow after 30 minutes, whereas lactate decreased only islet blood flow. These responses were absent in transplanted animals. A continuous intraportal infusion of lactate or pyruvate increased selectively islet blood flow but did not affect blood perfusion of transplanted islets.
Conclusions:
Lactate and pyruvate affect islet blood flow through effects mediated by interactions between the liver and the nervous system. Such a response can help adjust the release of islet hormones during excess substrate concentrations.
