Decrease of plasma glucose by allantoin, an active principle of yam ( Dioscorea spp.), in streptozotocin-induced diabetic rats.
The effect of allantoin, an active component of yam, on plasma glucose of streptozotocin-induced diabetic rats (STZ-diabetic rats) is investigated. Allantoin decreased plasma glucose levels in a dose-related manner, which was reduced by pretreatment with naloxone or naloxonazine. A concomitant increase in plasma β-endorphin, detected by enzyme-linked immunosorbent assay, was observed. Moreover, allantoin enhanced β-endorphin release from the isolated adrenal medulla of STZ-diabetic rat in a dose-related manner. However, its plasma glucose lowering action was reduced but not totally abolished by bilateral adrenalectomy. Furthermore, allantoin directly increased radioactive glucose uptake in isolated skeletal muscle, and repeated administration for 3 days increased GLUT4 mRNA and protein levels in muscle. This effect was markedly reduced in STZ-diabetic rats with bilateral adrenalectomy. This study suggests that allantoin increases GLUT4 gene expression in muscle by increasing β-endorphin secretion from the adrenal gland in STZ-diabetic rats.
Department of Nursing, Tzu Chi College of Technology, Hualien City, Taiwan 97041.
Chiang-Shan
CS
Niu
Wency
W
Chen
Hung-Tsung
HT
Wu
Kai-Chun
KC
Cheng
Ya-Ju
YJ
Wen
Kao-Chang
KC
Lin
Juei-Tang
JT
Cheng
D000481:Allantoin / Q000008:administration & dosage*; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D027742:Dioscorea / Q000737:chemistry*; D004195:Disease Models, Animal; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin / Q000009:adverse effects
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D000481:Allantoin; D013311:Streptozocin