A scorpion venom peptide fraction induced prostaglandin biosynthesis in guinea pig kidneys: incorporation of 14C-linoleic acid.
A peptide fraction isolated from the venom of the Egyptian scorpion Buthus occitanus was proved to have a bradykinin- potentiating activity. In vivo and in vitro modes of action of the isolated bradykinin-potentiating peptide (BPP) on kidneys of guinea pigs were investigated. Animals received five successive i.p. doses of the scorpion BPP (1 microg/g body weight) at one-week intervals. The control animals were i.p. injected with saline solution only. In vivo experiments showed a significant increase in renal tissue PGE(2) content and lipid peroxides of the treated guinea pigs compared to the control animals (p < 0.05). Nonsignificant changes were detected in the levels of tissue c-AMP and 5-nucleotidase activity (p > 0.05) of the treated animals, while the changes in c-GMP and c-AMP/c-GMP ratio were both significant (p < 0.05). In vitro experiments demonstrated enhanced capacity of guinea pig-renal tissue to convert (14)C-linoleic acid to its metabolites, 6-keto-PGF(1)alpha, PGF(2)alpha, PGE(2), TxB(2), PGD(2), and arachidonic acid, in response to the added PBP (1 microg/ml) and bradykinin (1 microg/ml). This enhanced response was abolished upon the addition of 1 microg/ml of BK-inhibitor (D-Arg- [Hyp(3), Thi(5,6), Phe(7)]). The capacity for labeled metabolites recovery in BPP treated renal tissue was 19.78%, while it was 13.00% in the basal control. The total increase that evoked by BPP was 62.78%. The results clearly indicate that the isolated BPP induced prostaglandin biosynthesis, which may trigger enhanced glomerular filtration in guinea pigs.
Department of Biochemistry, Faculty of Science, Alexandria University, Alexandria, Egypt. EL_saadaniM@hotmail.com
Muhammad A
MA
el-Saadani
D000818:Animals; D001681:Biological Assay / Q000379:methods; D002250:Carbon Radioisotopes / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D019787:Linoleic Acid / Q000378:metabolism*; D008297:Male; D010446:Peptide Fragments / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D011453:Prostaglandins / Q000096:biosynthesis*; D012604:Scorpion Venoms / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*
D002250:Carbon Radioisotopes; D010446:Peptide Fragments; D011453:Prostaglandins; D012604:Scorpion Venoms; D019787:Linoleic Acid