AJP - Endocrinology and Metabolism, Vol 252, Issue 5 E573-E580, Copyright © 1987 by American Physiological Society
Studies of gut and hepatic metabolism in conscious rabbits
M. C. Pere, M. Gilbert, R. Assan and F. C. Battaglia
The present study was designed to develop the techniques for chronic
catheterization of the hepatic and portal venous circulation in conscious
rabbits and to apply these techniques to a study of hepatic metabolism in
this species. Experiments were made after an 18-h fast and for 4 h after
the initial feeding. Measurements of arteriovenous differences of
substrates were combined with measurements of hepatic and gastrointestinal
blood flow. Hepatic glucose production was suppressed by 60% at 1 h and had
returned to control levels by 4 h. The hepatic uptake of lactate declined
slightly at 1 h and had returned to control level 2 h after the meal. There
was a marked and rapid fall in hepatic ketone body output after refeeding.
Although amino acid concentrations displayed a transient increase 1 h after
the meal, only the arterial concentration of branched-chain amino acids
remained significantly elevated for 4 h. The total hepatic uptake of the
gluconeogenic amino acids (alanine, serine, threonine) remained constant.
Refeeding resulted in a doubling of arterial insulin concentrations at 1 h
followed by a progressive decline over the next 3 h. It is concluded that
in rabbits fed a mixed meal partial suppression of hepatic glucose output
is mainly due to a decline in glycogenolysis rather than a decrease in
gluconeogenesis, shortly after refeeding the liver is able to virtually
shut off its ketone body production, the major gluconeogenic precursors
(lactate, alanine, glycine, serine, and threonine) may contribute to
approximately 40% of the glucose release.(ABSTRACT TRUNCATED AT 250 WORDS)
