Antihyperglycemic effect of catalpol in streptozotocin-induced diabetic rats.
The antihyperglycemic effect of catalpol (1) purified from the roots of Rehmannia glutinosa was investigated in streptozotocin-induced diabetic rats (STZ-diabetic rats) representing insulin-dependent diabetes mellitus. Bolus intravenous injection of 1 showed antihyperglycemic activity in a dose-dependent manner in STZ-diabetic rats. An effective dose of 0.1 mg/kg 1 significantly attenuated the increase of plasma glucose induced by an intravenous glucose challenge test in normal rats. Catalpol enhanced the uptake of radioactive glucose in the isolated soleus muscle of STZ-diabetic rats in a concentration-related manner. Moreover, an effect by 1 was established on glycogen incorporation in hepatocytes isolated from STZ-diabetic rats. Catalpol was found to increase glycogen synthesis in STZ-diabetic rats. These results suggest that 1 can increase glucose utilization to lower plasma glucose in diabetic rats lacking insulin.
Huang
Wei-Jan
WJ
Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei 110, Taiwan, Republic of China.
Niu
Ho-Shan
HS
Lin
Mei-Hsiang
MH
Cheng
Juei-Tang
JT
Hsu
Fen-Lin
FL
D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects* / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood*; D005960:Glucosides / Q000494:pharmacology*; D006003:Glycogen / Q000032:analysis; D022781:Hepatocytes / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D057888:Iridoid Glucosides; D039823:Iridoids / Q000494:pharmacology*; D008297:Male; D015394:Molecular Structure; D018482:Muscle, Skeletal / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D032267:Rehmannia / Q000737:chemistry*; D013624:Taiwan
D001786:Blood Glucose; D005960:Glucosides; D007004:Hypoglycemic Agents; D007328:Insulin; D057888:Iridoid Glucosides; D039823:Iridoids; C078040:catalpol; D006003:Glycogen