A BRADYKININ-POTENTIATING FRACTION ISOLATED FROM THE VENOM OF EGYPTIAN SCORPION BUTHUS-OCCITANUS INDUCED PROSTAGLANDIN BIOSYNTHESIS IN FEMALE GUINEA-PIGS

A fraction with bradykinin potentiating activity was chemically isolat ed from the Venom of the Egyptian scorpion Buthus occitanus. The pharm acological activity of the fraction (BPF) was bioassayed by its abilit y to potentiate added bradykinin on the isolated guinea pig ileum as w ell as its inhibitory activity on angiotensin converting enzyme. The m ode of action of this fraction on gonads of immature female guinea pig s was studied. The fraction was i.p. injected I mu g/g body weight for five times in animals (about, 150 g) at successive time intervals of I days each. Total body, ovarian, and uterine tissue weights were sign ificantly increased as well as uterine total protein, RNA and cyclic n ucleotides contents. Concomitantly, PGF(2 alpha) level showed signific ant elevation in both uterine and ovarian tissues. The uterine tissue homogenates in vitro showed an enhancing effect in response to the add ed fraction (1 mu g/ml) and bradykinin (I mu g/ml) fbr prostaglandin b iosynthesis from radiolabelled precursor C-14-linoleic acid into its l abelled metabolites: arachidonic acid, PGD(2), TxB(2), PGE(2), PGF(2 a lpha), and 6-keto PGF(1 alpha). This enhancement effect was abolished in the presence of BK inhibitor but the labelled PGF(2 alpha) was stil l high, The results clearly indicate that the increase of PGs resultin g from both in vivo and in vitro experiments may contribute to the inh ibition of ACE and potentiation of exogenous and endogenous BK. (C) 19 97 Elsevier Science Inc.