Intravenous Self-Feeding: Long-Term Regulation of Energy Balance In Rats

Abstract
Rats learned to press a lever for intravenous self-injection of liquid diet during periods of several weeks when oral food was not available. The intakes were low but regulated, and were sufficient to balance energy expenditures at low body weight. Systemic receptors alone are thus adequate to motivate feeding behavior and meter the caloric yield of the intravenous injections.