The function of the adrenal medulla

Abstract

WE have reported in a previous note2, that under certain conditions extracts of the adrenal medulla show an activity which cannot be explained by the adrenaline present. This activity was apparently due to a substance similar to adrenaline, but more potent than the latter. Till a chemical name can be substituted we propose to call this substance "Novadrenine."It is not the object of the present paper to give an exhaustive analysis of the physiological activity of novadrenine. We only want to give fuller evidence of the existence of such a substance, and to call the attention of research workers to this field of investigation. The present authors feel incompetent to give a definite physiological analysis, and are greatly hampered in their work by the lack of material.The existence of novadrenine is based on the observation, that under certain conditions the potency of adrenal extracts is 10-15 times higher than would correspond to their adrenaline content, estimated chemically by a colorimetric method. This high activity was only observed if the glands were excised soon after death and cooled carefully. In a great number of experiments the adrenaline content of the ox medulla was estimated colorimetrically and was found to lie between 1-2 mg. per g. of tissue, whether the extract showed a high physiological activity or not. In active extracts the physiological activity corresponded to an adrenaline content of 15-30 mg. of adrenaline per g. of medulla, a difference which could hardly be explained by an experimental error. If this latter value were correct, the gland would contain 10-15 p.c. of adrenaline by dry weight, which is impossible. It was also frequently observed that during chemical manipulations the excess activity of the extracts suddenly disappeared, the values obtained by chemical analysis and physiological estimation being then in close agreement.

The effect of fumarate on respiration

“…In unbuffered Ringer solution the oxygen uptake of muscle was low (Q o2 = 1 ) ; fumarate failed to increase respiration, and malonate failed to inhibit it, which observation agreed with that of Szent-Gyorgyi (Annau et al, 1935). This low respiration could be attributed to a rapid increase in the acidity of the system and also possibly to a deficiency in necessary phosphate.…”

“…The pigeons were killed by " breaking the neck " . The breast muscle was removed immediately, cooled on ice for one-half minute, and ground in a Latapi mincer, the second disk of which had been removed to minimize damage to the tissue (Szent-Gyorgyi et al , 1935). Small amou weighed on cellophane on a torsion balance and added directly to the flasks.…”

“…Our first experiments were made with pigeon breast muscle using M/15 phosphate buffer according to the procedure of Szent-Gyorgyi et al (1935). * There appears to be no convenient term in the literature which indicates the amount of oxygen consumed by a unit of tissue at any given time.…”

Chemical Characteristics and Physiological Rôles of Glutamine.

“…Let us consider again the possible and likely precursors of the nitrogen-free skeletons of the amides. One may postulate from analogy (as has Chibnall (45, page 190)) that, as in muscle metabolism (3, 83, 306), enzyme systems are present which convert succinic acid through fumaric and Z-malic acids to oxalacetic and aspartic acids and that each of the four nitrogen-free acids (as is the case in muscle) (3,247,255) catalyzed oxidation. Just as such reactions could provide the precursors of asparagine, so citric acid or cis-aconitic (38,117) through the cycle of Krebs (114) and Johnson (120) could lead to the formation of a-ketoglutarate (146,147), glutamic acid, and glutamine.…”

Determination of Succinic Acid in Plant Tissues

“…More recent modifications of the silver salt method, designed for application to the analysis of animal tissues, have been described by several investigators (5, 7, 9,16). During the past few years, however, attention has been directed chiefly to methods that depend on the oxidation of succinic acid in the presence of an enzyme that occurs in muscle tissue (2,12,22). These methods are especially suited to the estimation of the minute amounts of suc: cinic acid that are encountered in the small samples of animal tissue employed for the study of the details of metabolism.…”