LVV-HEMORPHIN AND VV-HEMORPHIN - COMPARATIVE LEVELS IN RAT-TISSUES

Screening of hemorphins in estracts of rat lung, brain, heart and sple en was carried out. The threshold for detection of hemorphins was 0.01 nmol for spleen and 0.05 nmol far other tissues. Both the content and the composition of hemorphins differed significantly in the tissues a nalyzed. Heart and lung extracts were rich in these peptides, the cont ent of the most abundant components reaching 16-44 nmol/g of tissue. I n contrast, spleen and brain contained much lon et amounts of hemorphi ns, i.e. about 0.3-2.6 nmol/g of tissue. The most represented hemorphi n in lung, heart and brain was VV-hemorphin-5, while the content of ot her members of the hemorphin family depended significantly on the tiss ue analyzed: lung extract was also rich in LVV-hemorphin-5, heart cont ained similar amounts of LVV-hemorphin-7 and LVV-hemorphin-5 and brain of LVV-hemorphin-6. In contrast, the hemorphin family in spleen was r epresented mainly by C-terminally shortened VV-hemorphins, i.e. VV-hem orphin-4 and VV-hemorphin-3. The levels of hemorphins in all cases wer e sufficient to activate the opioid receptors of the respective tissue s. (C) 1998 Federation of European Biochemical Societies.