Sauvagine induces release of adrenocorticotropin, beta-endorphin and corticosterone in rats

The effect of sauvagine, a frog skin peptide, on ACTH, beta-endorphin and corticosterone secretion, was studied in rats. A subcutaneous injection of 5 micrograms kg-1 of sauvagine in rats produced a prompt increase in immunoreactive plasma concentration of ACTH and beta-endorphin, which reached a peak value 15-30 min after the peptide injection. The stimulatory action of sauvagine on ACTH and beta-endorphin secretion was dose related. Intensity and duration of corticosterone secretion, produced by sauvagine mediated ACTH release, was dose-dependent, the threshold dose being 0,5 microgram kg-1 s.c. Pretreatment of rats with dexamethasone-21-phosphate, prevented the corticosterone releasing effect of sauvagine. Sauvagine perfusion (2,1 nM/h) of biogel columns containing isolated and dispersed anterior pituitary cells induced a sharp increase of ACTH levels in the eluate. Considering the high corticotropin releasing potency of sauvagine and its chemical similarity to ovine CRF, it is interesting to hypothesize whether this peptide may represent, in lower vertebrates, an ancestral form of the mammalian hypothalamic releasing factor.