SCIENTIFIC PROGRESS

Waipa Post, Volume 45, Issue 3208, 26 July 1932, Page 8

SCIENTIFIC PROGRESS

A POWERFUL HORMONE. j l (By G.K. in Melbourne Age.) ' In IsWS, whiie trying uie effect of [ injection of extracts made from vari- I ous animal tissues, Oliver and Schafer discovered that, while most of such extracts produced a fall of blood pressure, two of them produced a remarkable rise. The two extracts were made from the suprarenal and pituitary "bodies" respectively. The former, as its name suggests, is situated on top of the kidney; the latter is situated just above the roof of the mouth, inside the skull, and connected with the underside of the brain by a slender stalk. Although these structures are so differently situated, too much emphasis must not be laid upon the fact, since these "bodies" are now known to be developed largely from the nervous system though each in a different manner. It is weli to remember this connection with the nervous system when later the functions of these organs are reviewed. As in the case of the thyroid gland, these organs have no ducts to lead away any secretion, and they were, like the thyroid, called "bodies" their gland function being completely overlooked. Oliver and Schafer's experiment was startling in its results. The extracts of these glands produced an immediate and excessive rise in the blood pressure. |ln the case of the extracts of the suprarenal body not the least important effect was an associated increase in the rate of the heart as well as in the power of its beat. Some 40 years previous to this Thomas Addison, ot Guy's Hospital, had demonstrated that the disease which now bears his name was associated with progressive destruction of the suprarenal bodies, and, although the disease could not be produced by surgical removal of these mysterious organs, their removal was found to cause death. Schafer's experiment, therefore, was all the more significant in that it cleai'ly demonstrated that these small glands secreted a substance sufficiently potent to produce a profound stimulation of the circulation. To-day it is one of the most valuable natural "remedies" that the physician possesses. It is a hormone. It finds its way into the blood stream directly, and then it circulates away in a more or less constant amount. One of its functins is to maintain the blood pressure at such a level as is essential to the working needs of the body, and this is achieved by its combined action on the muscle of the walls of the arteries, and upon the mechanism of the heart itself.

Tournade has recently shown beyond a doubt that the slightest fall in blood pressure instantly results in the secretion of more adrenalin into the blood stream, while the least rise in blood pressure produces a diminution of the secretion. In addition to the effect on the cir-

culation of the blood, it was soon found that there were other, and, at first sight, most divergent action of this hormone. An injection of the substance produces, in addition to the effect mentioned, a transient dilation of the pupils of the eye and a separation of the lids, a cessation of the movements of the intestine, an increase in the amount of sugar in the blood, together with a more rapid combustion of sugar, and an elevation of the hairs of the skin. These apparently deverse phenomena are produced in states of fear or prysical emergency.

Blood is required for the muscles to exercise rapid and powerful movements—either of flight or for fighting. The muscles not only require more fuel in the form of sugar, but they require to burn it more rapidly (compare with the forced draught in a locomotive). If the blood is required for the muscles it must be diverted from the intestines, which are for the time reduced to quiecence. Finally, it may be of assistance to add to the general readiness of the whole animal. A formidable appearance of this is achieved by the eye and fur effects mentioned —we even know them ourselves, the elev'ition of the hairs give's the appearance and sensation of "goose flesh." One's skin creeps. It will be seen that we are here dealing with a powerful hormone whose task, it would appear, is to regulate and co-ordinate those functions of the body which are involved in the state of preparedness for muscular effort. Whether we "face the music" or run away, the hormone from the suprarenal gland produces the same series of phenomena within the body, which, acting together, enable use to obey efficiently the dictates of the will.

The chief importance of the hormone as a therapeutic agent lies in its effect upon the circulation. In certain cases where the blood pressure is low and the heart's action weak an injection of adrenalin may be the means of saving life. Its effect upon the walls of the arteries is to be contrasted with its effect upon the muscle of the air tubes or bronchioles of the lungs. These muscles relax under its influence, an effect seen chiefly when they are in a state of spasmodil contraction. There are certain types of asthma known to be due to such muscular spasm, and an injection of adrenalin in these cases brings immediate relief to the patient.