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.
el-Saadani
Muhammad A
MA
Department of Biochemistry, Faculty of Science, Alexandria University, Alexandria, Egypt. EL_saadaniM@hotmail.com
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