Bloodglucose and FFA levels in relation to the meal pattern in the normal rat and the ventromedial hypothalamic lesioned rat

Abstract

A method is described to take numerous blood samples with short time intervals from unanesthetized and undisturbed rats by means of a chronic intracardial catheter. Blood glucose and FFA levels are determined in relation to food intake and meal patterns both in intact and (electrolytically) brain lesioned (ventromedial hypothalamus) rats. Between meals the blood glucose level in intact rats is fairly constant, showing a peak during a meal. During the dynamic phase of the brain lesioned and hyperphagic animals, blood glucose level is comparable to that of intact rats, although the peaks during a meal are frequently absent. FFA levels, being the same both in intact and lesioned animals, show a course roughly the inverse of that of glucose in both types of animals. When food is removed at the moment the animal will start a meal a slow but significant fall of the blood glucose level ensues. Such a decrease cannot be observed in hyperphagic animals when food is removed. After 24 hr of food deprivation the glucose level of intact and lesioned rats is low (80–90 mg %) and the FFA level is high (ca. 0.8 μeq/ml plasma). After returning the food, the glucose level rises rapidly, whereas the FFA level declines in both types of animals.