INACTIVATION OF ADRENALINE AND NORADRENALINE BY HUMAN AND OTHER MAMMALIAN LIVER IN VITRO

Abstract

In a previous paper, Bain, Gaunt, and Suffolk (1937) described a biological assay method for following the course of adrenaline inactivation in vitro. Using this method they showed, among other things: (1) that adrenaline was only partially inactivated in cats' defibrinated blood, and that this was largely owing to the slow passage of some of the adrenaline into the red cells, whence most of it could be recovered by laking; (2) that the addition of tissue slices, particularly of liver, to a blood-adrenaline mixture, determined a relatively rapid and complete inactivation of the adrenaline.In some subsequent work, not published in full, Bain and Dickinson (1938) showed that the mean rate of adrenaline inactivation by liver slices, as indicated by the half-inactivation time, varied with the species: it was fastest for the guinea-pig and for man, slowest for the cat, dog, and mouse, and intermediate for the rat. The results from 16 samples of human liver were reported at that time. Three of these inactivated adrenaline so slowly as to seem in a different category from the others. As two of the subjects had suffered from arterial hypertension of non-renal origin it was suggested that delayed inactivation of the transmitter of adrenergic vasomotor nerve activity-then thought to be adrenaline-might be responsible for such forms of raised arterial blood pressure.The importance of noradrenaline was not, of course, recognized when these observations were made. It seemed desirable, therefore, in the light of subsequent events, to compare the behaviour of noradrenaline with that of adrenaline. This has accordingly been done by repeating some of the earlier work, but in parallel experiments in which both drugs were investigated at the same time under the same conditions. Most experiments were with human liver.A preliminary note on some of the results has already appeared (Bain and Batty, 1952). MATERIALS AND METHODSDrug Solutions.-A concentrated stock solution of (-)-adrenaline hydrochloride was made by dissolving a known amount of the synthetic laevo base (British Drug Houses, Ltd.) in the calculated amount of 0.1 N-HCl, and adjusting the final volume with distilled water so that the solution contained 10 mg. base/ml. From this a dilute stock solution, containing 1 mg. base/ml., was prepared as required. A standard adrenaline solution, containing 10 pg. base/ml., was freshly prepared for each assay from the dilute stock solution.Laevonoradrenaline was at first used as the hydrochloride, and later as the bitartrate monohydrateboth kindly supplied by Dr. M. L. Tainter. A stock solution, containing 1 mg. base/ml., was prepared by dissolving the appropriate amount of the salt in distilled water (I mg. base = 1.22 mg. hydrochloride = 1.99 mg. bitartrate). Standard solutions for the assays were prepared by dilution of this stock solution.Stock solutions were kept in the refrigerator. During the course of an assay the standard solutions were kept cool on ice.Blood-Liver-Amine System.-Apart from a few preliminary experiments, whe...

The output of sympathetic transmitter from the spleen of the cat

“…At high frequencies the rate of noradrenaline release might exceed the maximum rate at which amine oxidase could destroy it. The accumulating transmitter would then spill over into the blood stream where it would be protected from destruction (Bain & Batty, 1956). This possibility was investigated by studying the effect of an inhibitor of monoamine oxidase on the output of sympathin at 10 and 30/sec.…”

Choline Phenyl Ethers as Inhibitors of Amine Oxidase

“…To do this, four or more blood and adrenaline samples are removed for assay at times ranging from S to about 90 min. The adrenaline assay and the estimation of the adrenaline content of the mixtures are described in detail by Bain et al (1937) and by Bain and Batty (1956). When the log adrenaline concentration is plotted against time, as in Fig.…”

“…Bain et al (1937) used, as a measure of the rate of adrenaline inactivation, the time taken to inactivate half of the original amount present; Bain andBatty (1952, 1956) took the regression coefficient of log adrenaline concentration against time. We have estimated the rate of inactivation by calculating the amount of adrenaline destroyed in 30 min.…”

Vitamin P – Do Certain Polyphenolic IMPS Have a Vital Function?

“…In vitro experiments showed that 2c is readily oxidized by catechol oxidase, the cytochrome system, amine oxidases, and peroxidases (86). Javillier and Lavollay supposed that Vitamin P slowed down oxidation and thereby the resulting inactivation of 2c (49,(87)(88)(89); 2c can also be inactivated by non-oxidative enzymes, such as catechol-Omethyltransferase. The ability of many different types of flavonoids and coumarins to affect the persistence of 2c was evaluated in a subsequent extensive study (85).…”