The effects of intracerebroventricular administration of biologically active peptides in conscious sheep.

The present study records the physiological effects of 24-hour intracerebroventricular infusion of a variety of biologically active peptides in conscious sheep. A number of peptides including AVP and TRH produced increases in mean arterial pressure, heart rate and body temperature. There was an overall positive correlation between peptide-induced changes in body temperature and changes in either mean arterial pressure or heart rate. TRH and beta-endorphin had marked effects on behaviour and several peptides reduced food and water intake. Several peptides increased urinary sodium excretion, however, few peptides changes plasma electrolyte concentrations. TRH produced small effects on plasma ACTH and plasma glucose concentrations. The peptides in this study produced physiological changes which were probably mediated by their actions on the central nervous system.