Magnitude of negative arterial-portal glucose gradient alters net hepatic glucose balance in conscious dogs.

Pagliassotti MJ, Myers SR, Moore MC, Neal DW, Cherrington AD
Diabetes. 1991 40 (12): 1659-68

PMID: 1684554 · DOI:10.2337/diab.40.12.1659

To examine the relationship between the magnitude of the negative arterial-portal glucose gradient and net hepatic glucose uptake, two groups of 42-h fasted, conscious dogs were infused with somatostatin, to suppress endogenous insulin and glucagon secretion, and the hormones were replaced intraportally to create hyperinsulinemia (3- to 4-fold basal) and basal glucagon levels. The hepatic glucose load to the liver was doubled and different negative arterial-portal glucose gradients were established by altering the ratio between portal and peripheral vein glucose infusions. In protocol 1 (n = 6) net hepatic glucose uptake was 42.2 +/- 6.7, 35.0 +/- 3.9, and 33.3 +/- 4.4 mumol.kg-1.min-1 at arterial-portal plasma glucose gradients of -4.1 +/- 0.9, -1.8 +/- 0.4, and -0.8 +/- 0.1 mM, respectively. In protocol 2 (n = 6) net hepatic glucose uptake was 26.1 +/- 2.8 and 12.2 +/- 1.7 mumol.kg-1.min-1 at arterial-portal plasma glucose gradients of -0.9 +/- 0.2 and -0.4 +/- 0.1 mM, respectively. No changes in the hepatic insulin or glucose loads were evident within a given protocol. Although net hepatic glucose uptake was lower in protocol 2 when compared with protocol 1 (26.1 +/- 2.8 vs. 33.3 +/- 4.4 mumol.kg-1.min-1) in the presence of a similar arterial-portal plasma glucose gradient (-0.9 vs. -0.8 mM) the difference could be attributed to the hepatic glucose load being lower in protocol 2 (i.e., hepatic fractional glucose extraction was not significantly different) primarily as a result of lower hepatic blood flow. In conclusion, in the presence of fixed hepatic glucose and insulin loads, the magnitude of the negative arterial-portal glucose gradient can modify net hepatic glucose uptake in vivo.

MeSH Terms (14)

Animals Arteries Blood Glucose Dogs Fasting Female Glucagon Insulin Lactates Liver Liver Circulation Male Portal Vein Somatostatin

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