Evidence for release of free glucose from muscle during amylin-induced glycogenolysis in rats.
Amylin, a 37 amino acid product of pancreatic beta-cells, inhibits insulin-stimulated radioglucose incorporation into muscle glycogen. In the current study, we exercised rats and then prelabelled the glycogen pool by infusing [3-3H]glucose along with glucose and insulin. Subsequent amylin administration increased the rate of appearance of tritiated water 6.4-fold, consistent with stimulation of glycogenolysis and passage of the released moieties through the hexose --> triose step of glycolysis. Further, there was an increase in plasma [3-3H]glucose after amylin, consistent with the release of free glucose previously sequestered in muscle glycogen. Calcitonin gene-related peptide (8-37), an amylin antagonist, prevented these actions.
Young
A A
AA
Department of Physiology, Amylin Pharmaceuticals Inc., San Diego, CA 92121.
Carlo
P
P
Smith
P
P
Wolfe-Lopez
D
D
Pittner
R
R
Wang
M W
MW
Rink
T
T
D000682:Amyloid / Q000494:pharmacology*; D000818:Animals; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D058228:Islet Amyloid Polypeptide; D008297:Male; D009132:Muscles / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000682:Amyloid; D058228:Islet Amyloid Polypeptide; D006003:Glycogen; D005947:Glucose