title: The correlation of cytophotometrically and biochemically measured enzyme activities: changes in the myocardium of diabetic and hypoxic diabetic rats, with and without Ginkgo biloba extract treatment.
abstract: Changes of enzyme activities in the myocardium of rats from 6 different experimental groups (normal rats, diabetic rats, hypoxic diabetic rats, each with and without Ginkgo biloba extract treatment) were measured by using both cytophotometric and biochemical methods. The activity of succinate dehydrogenase, a marker of oxidative capacity, and of menadione-dependent glycerol-3-phosphate dehydrogenase and total lactate dehydrogenase, both markers of glycolytic capacity were measured to characterize changes of the metabolic profile in myocardium. A strong correlation between cytophotometric and biochemical data were found by linear regression analysis, justifying the use of cytophotometrical enzyme activity measurements in cells of organized tissue, where biochemistry cannot provide topographical information. The comparison of the results obtained from the different groups revealed the following: Enzyme activities in the myocardium of rats with streptozotocin-induced diabetes were significantly increased by 10-30% as compared to the normal myocardium. This effect was interpreted as a metabolic compensation of the diabetic heart with reduced performance. When diabetic rats were exposed to acute hypoxia of 20 min duration, enzyme activities decreased under the normal level, to 56% of the succinate dehydrogenase activity, to 87% of glycerol-3-phosphate dehydrogenase activity and to 69% of lactate dehydrogenase activity. Treatment of rats with the oxygen radical scavenger Ginkgo biloba extract (EGb 761) over 3 months resulted primarily in an increase by 10% of oxidative capacity and in a decrease by 30% of glycolytic capacity. Under diabetic conditions a shift to more glycolytic metabolism was observed by increasing the glycolytic activity by 39% and remaining the oxidative activity.
authors.affiliation: Institute of Anatomy, University of Leipzig, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Punkt
authors.forename: V
authors.initials: V
authors.lastname: Adams
authors.forename: A
authors.initials: A
authors.lastname: Linke
authors.forename: K
authors.initials: K
authors.lastname: Welt
mesh_terms: D000818:Animals; D003592:Cytophotometry; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology; D016166:Free Radical Scavengers / Q000627:therapeutic use*; D020441:Ginkgo biloba; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects; D006321:Heart / Q000187:drug effects*; D000860:Hypoxia / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016014:Linear Models; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D010936:Plant Extracts / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D013385:Succinate Dehydrogenase / Q000378:metabolism; D000096983:Ginkgo Extract
chemical_list: D016166:Free Radical Scavengers; D005993:Glycerolphosphate Dehydrogenase; D007770:L-Lactate Dehydrogenase; D010936:Plant Extracts; D013385:Succinate Dehydrogenase; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract