Acute Effects on Metabolic Blood and Tissue Parameters in Conscious Rats

Acute Effects on Metabolic Blood and Tissue Parameters in Conscious Rats 

Conscious rats are used for testing the side effect potential of a candidate compound on intermediary metabolism in liver, muscle and adipose tissue with subsequent effects on metabolic blood parameters (e.g. glucose, lactate, free fatty acids, triglycerides) and insulin after oral administration, which represents in most cases the clinical route of administration for small molecular drugs. 

Rats weighing 180-240 g are kept on standard diet. Groups of 8 non-fasted animals are treated orally with various doses of the test compounds suspended in 0.4% starch suspension. One control group receives the vehicle only. Blood is withdrawn from the tip of the tail immediately before, and 1,2,3,5, and 24 hours after administration of the candidate compound. Blood glucose is determined in 10 pi blood samples collected from the tip of the tail. If pharmacokinetic data for the candidate compound are already available, when performing this test, additional blood samples (100 pi) should be taken at max by retro orbital bleeding for detection of free fatty acids, triglycerides and insulin. 

At the end of the experiment, the rats are terminally anesthetized, the abdomen is opened, and terminal blood collection is performed from the vena cava caud. or the aorta abdominalis for determination of metabolic blood parameters and insulin. A part of the liver is freeze clamped immediately as well as a part (about 1 gr) of skeletal muscle (e.g. M. gastrocne-micus). The frozen tissue is stored in liquid nitrogen for subsequent determinations of intrahepatic and intramuscular concentrations of glycogen, glucose-6-phosphate (G6P) and ATR In liver samples hepatic 

The differences of the metabolic blood parameters after compound administration are calculated against a control group, which has received the vehicle only, for the respective time points. The metabolic tissue parameters at the end of the study are assessed between control and treatment group. 

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