PLATELET ACTIVATING FACTORS (AGEPC) FROM EPIDERMAL SECRETIONS OF THE ARABIAN GULF CATFISH, ARIUS-BILINEATUS, WHICH STIMULATE WOUND-HEALING

High levels of platelet activating factor (PAF) activity were demonstrated by platelet aggregation and serotonin release assays to be present in fright induced epidermal secretions of the Arabian Gulf catfish, Arius bilineatus (Valenciennes, 1840). The PAF activity was purified by thin-layer chromatography. Mass spectral analysis combined with chemical and enzymatic modification of the purified PAF and inhibitor studies indicated that PAF activity was due to the presence of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine (AGEPC) molecules. The total AGEPC concentration in the epidermal secretions based on PAF assays was 8 . 10(-8) M, well above the threshold level for platelet activation which is near 5 . 10(-11) M. Thus, stimulated epidermal secretory cells of Arius bilineatus supply platelet activating molecules at physiologically high concentrations to sites of injury.