Reference

The effect of diatrizoate salts on vasopressin-induced volume flow across the excised toad urinary bladder

The effect of diatrizoate salts on vasopressin-induced volume flow across the excised toad urinary bladder. Gatzy, John T.; Mudge, Gilbert H. (Dep. Pharmacol., Dartmouth Med. Sch., Hanover, N. H., USA). J. Pharmacol. Exp. Ther., 204(2), 469-80 (English) 1978. CODEN: JPETAB. ISSN: 0022-3565. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacodynamics) In excised toad urinary bladder, a model for the mammalian distal nephron, when NaSO4, Na gluconate, or Na diatrizoate (I Na) [737-31-5] was the principal electrolyte, the increase in flow induced by vasopressin (ADH) [11000-17-2] was half that obsd. with NaCl solns. Resting flow was unaffected. Meglumine sulfate [66395-24-2] and I decreased the ADH response by 65 and 85%, resp. Meglumine I [131-49-7] inhibition was partially reversible, was induced with concns. as low as 35 mmol/L in the serosal soln. only andwas antagonized by NaCl (5 mmol/L). In addn., meglumine I decreased the vol. flow induced by theophylline or cyclic AMP. Resting transmural p.d. tended to be lower and to increase less after ADH in those tissues which did not respond with an increase in vol. flow, but the voltage response in the presence of serosal meglumine I was not inhibited. When bladders were mounted in a Ussing chamber under vol. flow conditions, serosal Na I, meglumine I, or meglumine sulfate depressed the ADH-induced increase in short-circuit current to about 45% of the response of a paired lobe in Na2SO4 soln. In addn., meglumine I blocked the increase in current at a concn. (25 mmol/L) that did not affect the vol. flow response to ADH. Incubation of the bladder with meglumine I reduced the QO2 to the same level as exposure to choline chloride. This observation suggests that the decrease with meglumine I is the consequence of the absence of Na+ rather than inhibition of basal oxidative metab. Thus meglumine I prevents the increase in vol. flow induced by ADH by interfering with a step beyond cyclic AMP and this action is not shared by the Na salt or by other poorly permeant salts which antagonize the short-circuit current response. An inhibition of the action of ADH on the renal tubule may contribute to the relatively low osmolality of the urine that is excreted after parenteral administration of meglumine I.

Study of the action of x-ray contrast media on the rate of NADPH and NADH oxidation by rat liver microsomes

Study of the action of x-ray contrast media on the rate of NADPH and NADH oxidation by rat liver microsomes. Sergeev, P. V.; Bol'shev, V. N.; Khalilov, E. M. (Med.-Biol. Fak., II Mosk. Med. Inst., Moscow, USSR). Farmakol. Toksikol. (Moscow), 40(4), 445-7 (Russian) 1977. CODEN: FATOAO. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacodynamics) Bilignost [606-17-7], cardiotrast [300-37-8], triiotrast [129-63-5], and triombrin [737-31-5] at 5mM decreased the oxidn. rate of NADPH [53-57-6] by rat liver microsomes but did not affect (except for triiotrast) the oxidn. rate of NADH [58-68-4]. The comparative resistance of the NADH-specific flavoproteins is probably due to the presence of a hydrophobic layer impervious to the polar mol. of the contrast media.