NEOKYOTORPHIN AND NEOKYOTORPHIN (1-4) - CYTOLYTIC ACTIVITY AND COMPARATIVE LEVELS IN RAT-TISSUES

The content of biologically active hemoglobin fragment neokyotorphin ( TSKYR) as well as that of neokyotorphin fragment (1-4) (TSKY) were det ermined in extracts of lung, heart, and brain tissue of rats. The cont ent of both peptides as well as the neokyotorphinineokyotorphin(1-4) r atio differed significantly from each other in these tissues. The resp ective parameters deviate considerably from those of erythocytes where these peptides are originally formed. Comparative analysis of cytolyt ic activity of peptides was performed at human erythroid leukaemia (K5 62) and murine transformed fibroblast (L929) cell lines. TSKY showed r eliable cytolytic activity in both cell lines, while neokytorphin was not cytotoxic. The data obtained lead to speculation that endogenous h emoglobin fragments might participate in regulation of tumor growth in vivo. (C) 1996 Academic Press, Inc.