Purification and characterization of Atlantic salmon prolactin.
Prolactin was isolated from the Atlantic salmon (Salmo salar) pituitary gland by extraction with acid acetone, gel filtration, ion exchange-chromatography, and reversed-phase high-performance liquid chromatography. The yield was 0.6 mg/g wet tissue. The hormone had a molecular weight of 23.5 kDa as determined by SDS- polyacrylamide gel electrophoresis. Isoelectric focusing gave an isoelectric point of 9.2. The N-terminal sequence and the amino acid composition indicated extensive homology between Atlantic and Pacific salmon prolactin. Antiserum against Atlantic salmon prolactin cross-reacted with chum salmon prolactin, but not with human, rat, or sheep prolactin.