Summary
Although it has been firmly established that D-glucose inhibits glucagon secretion
from pancreatic A cells, the regulatory mechanism of glucagon secretion by D-glucose
has not been elucidated. To study this regulatory mechanism by D-glucose, the effects
of hexoses and their derivatives on glucagon secretion from the A cells of isolated
perfused rat pancreas were investigated. When these cells were perfused with D-glucose,
D-fructose, D-sorbitol, D-galactose, 2-deoxy-D-glucose, D-gluconic acid sodium salt
and D-glucosamine HCl salt, glucagon secretion was significantly inhibited. None of
the hexoses or their derivatives tested were found to stimulate glucagon secretion.
The effects of these sugars on glucagon secretion were independent of their metabolism
in the cells. From the findings that the sugars both metabolized and unmetabolized
in the cells demonstrated comparable inhibition of glucagon secretion from the isolated
perfused rat pancreas, it is speculated that the recognition system for these sugars
may be probably present on the A cell membrane and responsible for mediating these
inhibitory effects of glucagon secretion.
Key words
A Cell Membrane - Glucagon Secretion - Recognition System for Hexoses - Isolated Perfused
Rat Pancreas
