HQL-975 (3-{4-12-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxyl-phenyl}-2S- propylamino-
propionic acid) is a new oral antidiabetic agent which has been shown to be effective in
insulin-resistant diabetic animals. In the present study, we examined the effects of
HQL-975 on
glucose utilization and
insulin action in KK-Ay mice with genetically obese non-
insulin diabetes. (1) Dietary administration of
HQL-975 (19 mg/kg/d for 7 d) improved
hyperglycemia,
hyperlipidemia and
hyperinsulinemia in the mice. (2) The HQL-975-treated mice showed enhanced net
glucose utilization, that is,
glucose was significantly incorporated into total
lipids in the white adipose tissue (WAT) and liver, and into
glycogen in the diaphragm for the last 24 h of the drug administration period. (3) Treatment improved the decreased stimulative action of
insulin in the epididymal WAT and the agent increased
insulin-stimulated lipogenesis from both
glucose and acetate. (4) Treatment also increased the activity of lipogenic
enzymes such as
glycerol-3-phosphate dehydrogenase and fatty acid
synthetase. (5) In vitro exposure of WAT to
HQL-975 enhanced lipogenesis in the presence of
insulin. From these findings, we conclude that
HQL-975 improves
glucose utilization of KK-Ay mice through the enhancement of
insulin action, which is associated with its lipogenic effects.