Effects of short-term nocturnal and diurnal food deprivation on subsequent feeding in intact and VMH lesioned rats: relation to blood glucose level.

Ad lib feeding responses were studied in VMH lesioned rats, following 2 to 6 hours of food deprivation during the dark and the light phases of the diurnal cycle. The correlation between glucose level at the time of restoration of food and these feeding responses was examined. At night, VMH as well as intact rats increased their food intake significantly following 2 to 6 hours of food deprivation. In both groups, the responses were correlated with a decrease in blood glucose which was dependent on the duration of previous food deprivation. During the day, in normal rats, food deprivation did not induce a change either in subsequent food intake or in blood glucose level. On the contrary, VMH lesioned rats increased their food intake following diurnal food deprivation as they did at night. But, surprisingly, this increase was not associated with a fall of blood glucose.