MIF-1 and Tyr-MIF-1 fail to alter benzodiazepine-induced hypothermia.

Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) and MIF-1 (Pro-Leu-Gly-NH2) can increase GABA-stimulated benzodiazepine binding in brain tissue can block the hypothermia induced by several other compounds. Since benzodiazepines can also cause hypothermia, colonic temperatures were measured in mice after administration of chlordiazepoxide (CDP) and these two brain peptides. In several experiments involving different doses and times of administration of CDP, MIF-1, and Tyr-MIF-1, there were no significant effects of the peptides in altering the reliable decrease in colonic temperature induced by the benzodiazepine. The results indicate that the interaction of Tyr-MIF-1 and MIF-1 with benzodiazepines does not involve thermoregulation.