Hormonal and metabolic characteristics of genetically obese Zucker and dietary obese Sprague-Dawley rats.

The endocrine-metabolic plasma pattern and the capacity of isolated perfused livers to produce triglycerides and ketone bodies have been studied in genetically and diet-acquired obese rats (Zucker and Sprague-Dawley obese rats), and in control groups of the same strains. An increased plasma insulin/glucagon molar ratio with hyperinsulinaemia and hypoglucagonaemia was associated with hypertriglyceridaemia, normal ketonaemia, elevated free fatty acids and normal or slight hyperglycaemia in obese rats. During oleate perfusion, the livers of Zucker and Sprague-Dawley obese rats showed an increase in triglyceride output and liver triglyceride content. The ketone body output as well as the mitocondrial carnitine palmitoyl transferase activity were normal or slightly decreased. In our rat population, a positive correlation between the insulin/glucagon molar ratio and triglyceride output has been found.