Caerulein precursor fragment (CPF) peptides from the skin secretions of Xenopus laevis and Silurana epitropicalis are potent insulin-releasing agents

► Skin secretions of Xenopus laevis and Silurana epitropicalis contain multiple CPF peptides. ► CPFs stimulate insulin release from BRIN-BD11 cells at concentrations as low as 30 pM. ► Mechanism of action involves membrane depolarization and increase in intracellular [Ca2+].