A method of treating diabetes can include administering a therapeutically effective amount of a composition comprising a soluble protein fraction obtained from epidermal gel secretions of catfish to a patient in need thereof. The soluble protein fraction can include soluble proteins and lipids from the epidermal gel secretions of catfish. The soluble protein fraction can include about 87% of the soluble proteins and about 13% of the lipids. The composition can be administered by intraperitoneal (IP) or sub-cutaneous (SC) injection.
