Effects of Dexamethasone on the Body Weight Set Point of Rats

Adult Wistar male rats were given dexamethasone in their drinking water. Food-hoarding behavior was measured repeatedly, and plotted against the animals' body weights. Body weight set point was estimated as the intersection of the regression line of hoarding with the X axis, i.e. as the threshold at which hoarding appears when body weight drops, and disappears when body weight returns to its initial value. Body weight set point was obtained before and during dexamethasone treatment. Control rats underwent the same sequence without dexamethasone in their drinking water. The hoarding threshold was raised when rats ingested low doses of dexamethasone, and was lowered when they ingested high doses. These results are discussed in the light of CRH as the main signal for the body weight set point.