DISTRIBUTION OF TISSUE KALLIKREINS IN LOWER-VERTEBRATES - POTENTIAL PHYSIOLOGICAL ROLES FOR FISH KALLIKREINS

Fish skeletal muscle prokallikrein was purified from black sea bass, C entropristis striata, and used for the production of polyclonal antise rum. Tissue proteins from primitive fish and teleosts, an alligator, a nd an insectivore were resolved by sodium dodecylsulfate-polyacrylamid e gel electrophoresis, Western blotted, and probed with fish muscle pr okallikrein antiserum. A recurring theme was the presence of approxima tely 36 and 72 kDa kallikrein-like proteins in skeletal muscle, heart, girl, kidney, and spleen of higher teleosts and in selected tissues o f sturgeon, shark, alligator, and mole. The presence of immunoreactive kallikreins in osmoregulatory organs such as the gills of teleosts an d the rectal gland of sharks signifies a potential role for these prot eins in osmoregulation. Black sea bass, rock bass, and sturgeon contai ned many immunoreactive kallikreins in their swimbladders, which impli cates a role for kallikreins in the regulation of blood flow and vascu lar permeability to facilitate gas exchange within the bladder. Kallik reins were consistently identified in skeletal muscle and heart of all the species evaluated and may regulate local blood flow, muscle contr action or relaxation, or participate in various transport processes. T he antiserum to fish prokallikrein recognized immunoreactive kallikrei ns from pancreatic tissues from fish and lower vertebrates, but not fr om the pyloric caecum of sea bass. The wide distribution of tissue kal likrein in lower vetebrates suggests that it may participate in a vari ety of physiological functions. (C) 1997 Elsevier Science Inc.