Sauvagine: effects on thermoregulation in the rat.

Sauvagine is a 40 amino acid peptide, isolated from the skin of the South American frog, Phyllomedusa sauvagei, and structurally related to mammalian corticotropin releasing factor (CRF). Experiments with centrally or peripherally injected sauvagine produced dose-dependent hypothermia in rats kept at ambient temperatures of +4 degrees C and +22 degrees C, but no effect was seen on rats maintained at +34 degrees C. To determine whether a pituitary-adrenal dependent step was involved, the thermoregulatory response was studied in hypophysectomized, adrenalectomized and sham-operated rats maintained at a room temperature of +22 degrees C. Significant hypothermia was produced in all three experimental groups, showing that this response is not mediate by the pituitary-adrenal axis. CRF had no effect on the thermoregulatory functions of rats and furthermore alpha-helical CRF (9-41), a CRF receptor antagonist, which inhibited the pituitary and cardiovascular actions of sauvagine, did not modify the thermoregulatory response in rats.