Regulation of Discreet Intermeal Intervals in Free-feeding Rats by Exogenous IL-1beta
Andrew Kurt Thaw, Kimberly A. Parker

Abstract
This study represents an investigation of the physiology of normal feeding behavior focusing primarily on an immune factor that is hypothesized to contribute to the maintenance of the interval between meals. The immune factor interleukin-1beta (IL-1) was examined as a potential regulator of spontaneous feeding in rats with regards to satiety. Discrete patterns of feeding were analyzed to identify changes in postprandial satiety following the infusion of three concentrations of IL-1as well as IL-1antibody and a control saline solution. Three groups of 8 rats were fed ad libitum with food intake continuously monitored. After the first nocturnal meal, the rats received an intraperitoneal injection of either the IL-1 cytokine, IL-1 antibody or the control solution. The inter-meal interval immediately following the injection was examined to determine the effects of IL-1 on feeding behavior. Results indicate that exogenous IL-1 significantly extends the length of time between the first and second nocturnal meals. In addition, the total food intake over a 23hr ad libitum feeding period was significantly reduced following IL-1 administration. This suggests that certain cytokines act as part of the cascade of events that combine to regulate feeding and appetite in mammalian models.

Full Text: PDF