title: In vivo effects of diabetes, insulin and oleanolic acid on enzymes of glycogen metabolism in the skin of streptozotocin-induced diabetic male Sprague-Dawley rats.
abstract: The skin is the largest organ in the body and diabetes induces pathologic changes on the skin that affect glucose homeostasis. Changes in skin glycogen and glucose levels can mirror serum glucose levels and thus the skin might contribute to whole body glucose metabolism. This study investigated the in vivo effects of diabetes, insulin and oleanolic acid (OA) on enzymes of glycogen metabolism in skin of type 1 diabetic rats. Diabetic and non-diabetic adult male Sprague-Dawley rats were treated with a single daily dose of insulin (4 IU/kg body weight), OA (80 mg/kg body weight) and a combination of OA + insulin for 14 days. Glycogen phosphorylase (GP) expression; and GP, glycogen synthase (GS) and hexokinase activities as well glycogen levels were evaluated. The results suggest that diabetes lowers hexokinase activity, GP activity and GP expression with no change in GS activity whilst the treatments increased GP expression and the activities of hexokinase, GP and GS except for the GS activity in OA treated rats. Glycogen levels were increased slightly by diabetes as well as OA treatment. In conclusion diabetes, OA and insulin can lead to changes in GS and GP activities in skin without significantly altering the glycogen content. We suggest that the skin may contribute to whole body glucose homeostasis particularly in disease states.
authors: Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Block F3 04-025, Private Bag X54001, University Road, Durban, 4000, South Africa.
authors: Andrew
authors: A
authors: Mukundwa
authors: Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Block F3 04-025, Private Bag X54001, University Road, Durban, 4000, South Africa.
authors: Silvana O
authors: SO
authors: Langa
authors: Discipline of Biological Sciences, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Block F3 04-025, Private Bag X54001, University Road, Durban, 4000, South Africa.
authors: Samson
authors: S
authors: Mukaratirwa
authors: Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Block F3 04-025, Private Bag X54001, University Road, Durban, 4000, South Africa. Electronic address: masolab@ukzn.ac.za.
authors: Bubuya
authors: B
authors: Masola
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism*; D024981:Glycogen Phosphorylase / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism; D007328:Insulin / Q000008:administration & dosage*; D008297:Male; D009828:Oleanolic Acid / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D013311:Streptozocin; D014166:Transferases / Q000378:metabolism*
chemical_list: D007328:Insulin; D013311:Streptozocin; D009828:Oleanolic Acid; D006003:Glycogen; D014166:Transferases; D024981:Glycogen Phosphorylase; D006593:Hexokinase; D005947:Glucose
keywords: Diabetes; Glycogen phosphorylase; Glycogen synthase; Hexokinase; Oleanolic acid