EFFECTS OF SELECTIVE VAGOTOMY ON CIRCADIAN-RHYTHMS OF PLASMA-GLUCOSE,INSULIN AND FOOD-INTAKE IN CONTROL AND VENTROMEDIAL HYPOTHALAMIC (VMH) LESIONED RATS

Effects of hepatic and celiac vagotomy on circadian rhythms of plasma glucose, insulin, and food intake were examined in sham-operated (cont rol) and vetromedial hypothalamic (VMH) lesioned rats. Rats were accli mated to the condition with a 12-hour light-dark cycle for 1 week befo re surgery, One week after VMH lesions, control and VMH lesioned rats were divided into three groups: sham vagotomy, hepatic vagotomy, and c eliac vagotomy, Three days after vagotomy, food intake was measured at 6-hour intervals, Seven days after vagotomy, plasma glucose and insul in were measured at the midpoint of each feeding period. In control ra ts, hepatic vagotomy destroyed circadian rhythms of plasma glucose and insulin probably due to removal of afferent function, In VMH lesioned rats, celiac vagotomy destroyed circadian rhythm of food intake due t o the reduction of plasma insulin by removal of efferent function with out affecting the loss of circadian rhythms of plasma glucose and insu lin.