AJP - Endocrinology and Metabolism, Vol 248, Issue 1 44-E50, Copyright © 1985 by American Physiological Society
Blood glucose homeostasis in rats with a deficiency of liver phosphorylase kinase
J. C. Conaglen, A. B. Williams, R. S. Malthus, D. Glover and J. G. Sneyd
The glycogen storage disorder (gsd/gsd) rat has little or no phosphorylase
kinase activity in the liver and is unable to break down liver glycogen on
fasting. Nevertheless, gsd/gsd rats do not become hypoglycaemic on fasting.
Gsd/gsd rats showed a decreased rate of glucose turnover measured with
[6-3H]glucose. Perfused livers from gsd/gsd rats showed decreased rates of
gluconeogenesis from lactate and alanine when the results were expressed
per gram of liver, but the total glucose produced per liver was normal.
Measurement of gluconeogenesis in vivo using [14C]-bicarbonate showed that
gsd/gsd rats had a decreased rate of glucose production from substrates
that enter the gluconeogenic pathway before pyruvate. We conclude that
gsd/gsd rats have adapted to unavailability of liver glycogen by decreasing
peripheral uptake of glucose and not by increasing gluconeogenesis.
