SAUVAGINE

Discovery

Sauvagine was first reported in the skin of the South American frog Phyllomedusa sauvagei in 1980. Novel forms of SVG were isolated in the skin of the Mexican giant leaf frog Pachymedusa dacnicolor in 20122 and the South American orange-legged leaf frog Phyllomedusa hypochondrialis in 2015.

Structure

The sauvagines of Phyllomedusa sauvagei (PS-SVG), Pachymedusa dacnicolor (PD-SVG), and Phyllomedusa hypochondrialis (PH-SVG) comprise 40 aa, 38 aa, and 40 aa residues, respectively, with a pyroglutamate at the N-terminus and an amidated C-terminus1–3 .  The sequence identity of PS-SVG with human CRH is 63%. The sequence identities of PS-SVG with carp urotensin-I, human urocortin-I, human urocortin-II, and human urocortin-III are 50%, 35%, 20%, and 25%, respectively.  PS-SVG, Mr 4599. Soluble in water and methanol.

Receptors

Two CRH receptors, type-1 and -2 CRH receptors (CRHR1 and CRHR2), have been identified in Xenopus laevis. PS-SVG has higher affinity to CRHR2 (Kd=0.9 nM) than to CRHR1 (Kd=51.4 nM). [Tyr0 , Gln1 , Leu17]SVG (YQL-SVG) and [Tyr0 , Gln1, Bpa17]SVG (YQB-SVG) have been identified as agonists.

Synthesis and release

PD-SVG cDNA encodes 80-aa precursors. Prepro PD-SVG consists of a signal peptide (22 aa), a spacer peptide (16 aa), a cryptic region, and a mature peptide of 38 aa residues at the C-terminus.

Biological functions

SVG stimulates ACTH release from the pituitary of rats and goldfish. In Xenopus, SVG stimulates the α-melanocyte-stimulating hormone and β-endorphin release from the pars intermedia of the pituitary. SVG in the skin is considered to be involved in chemical defense.

Description

Sauvagine is a peptide hormone, first isolated from the skin of the South American frog Phyllomedusa sauvagei, with adrenocorticotropic hormone (ACTH)-releasing activity and antidiuretic activity.