Altered body temperature of rabbits after central injection of β-endorphin and other peptides

After injection of 5 μg into a lateral cerebral ventricle, 6 of 12 peptides induced mean changes of 0.3 °C or more in rectal temperature of rabbits. When β-endorphin was studied further with 1.25–5 μg in 10, 23 and 30 °C environments, it induced dose-related hypothermia in the cold, hyperthermia in the heat and progressively smaller increases in body temperature with increasing doses at 23 °C.