GLANDS AND THEIR WORK

Evening Star, Issue 21994, 2 April 1935, Page 10

GLANDS AND THEIR WORK

A CHEMICAL LABORATORY THE SIZE OF AREA SOME RECENT DISCOVERIES Most people are familiar with the names, even if they do not understand ,*he actions, of those mysterious substances called “ vitamines,” which must be consumed in minute quantities, in our diet to ensure perfect health. JV’ery few, on the other hand, realise that there are probably scores of equally important substances circulating in the blood in even more minute quantities, which are elaborated in the body itself and are necessary for our wellbeing and even life itself. These selfmade chemical substances are ■ called v hormones.” They are manufactured ; in the endocrine or ductless glands, from which they are passed directly into the blood stream to produce their effects throughout the body. Forty years ago the presence of these sub•tances may have been suspected, but it is safer to say that nothing was known of'-them (writes John Beattie, M.D., in ‘ John o’ London’s Weekly ’). Dr Beattie is conservator of the museum and director of research, Royal .College of. Surgeons' of England. : To-day the dried thyroid glands 'Of hnimals, or the “ hormone ” or active principle of, them, are fed to patients who suffer from defective secretion of .their’ own glands. Diabetes, caused by the absence of a hormone called “ insulin,” is treated by extracts containUg .the hormone. Attempts have been made to transplant pieces of the sex glands of monkeys and apes into mail, in the hope that . the “ hormones ” elaborated in the person’s glands may be supplemented and that “ rejuvenescence ” may ensue. KEEL PLATE OF BRAIN. As work on the endocrine glands has proceeded, attention has been concentrated on the pituitary gland, lying in a small recess in the bone forming the keel plate, of the brain box. It is attached to the base of the brain by a thin, short stalk, and in man is about the size of a small pea., When examined it is seen to consist of three sectoins—a front and back part separated by a thin intermediate portion. There are thus probably three glands. iWe shall see that each part has probably a multiplicity of. “ hormones ” to produce for the good ordering and developing of the body. The anterior or front part is now known to elaborate at least five distinct substances which produce positive • actions, and two substances which have the effect of suppressing activity of other glands in the body. The posterior and intermediate parts, are peculiar in , their effects., but it is believed that three (at least) “ hormones ” are produced in these fwo parts. Thus in the size of a pea is a chemical laboratory which determines whether a child shall be a giant or a .dwarf, an idiot or a normal person, or remain a child, sexless and undeveloped. It may also' determine: whether or not a person shall die of diabetes, high blood pressure, or three or four other diseases which are rarely seen. . - Mane, a .famous French physician, recorded that cases .of a peculiar disease known as acromegaly were always associated with an enlargement or a tumour of the pituitary gland,' Acromegaly, we now know, is due to an excess of the secretion made .by the front or anterior part of the pituitary • gland. This excessive ; secretion causes, amongst other things, an overgrowth of bone which distorts the facial contours and the shape of the hands and'feet. If the secretion is excessive during childhood, it results in the production of a giant. So acromegaly is due-to the overproduction during adult life of a substance which normally -controls the growth rate of .the body, and especially that of the skeleton. This substance is a “ growth hormone.” When it is lacking a certain kind of dwarf is produced. Me have no, idea at the moment how the rate of secretion of the growth nprmone is controlled. While it is still true to say that no man can add. an inch to-his stature “by taking thought,” yet animals much larger than normal can be produced by the prolonged injection of “ growth-produc-ing ’’ extract from the anterior part of the gland. Animals deprived of this part. of the gland do not grow, blit can be made to resume their normal rate of growth by injections of the “ growth ” extract. The other four active principles or hormones ” of the anterior pituitary gland seem to control the activity of four different glands. Young and immature animals deprived of their pituitary glands by experimental methods of by tumours which destroy the pituitary do not develop into normal adults capable of reproducing their kind, even if the growth hormone is administered by. injection. Something is lacking to transform the growing animal into the adult; The “hormone” which control’s the development of the sex glands and’ reproductive organs not only influences these parts of the body, but by stimulating the sex glands to ac- . tivity it brings about those subtle changes which gradually . transmute thechild into the adult man or woman. This hormone may be called the “maturation or “ adolescense ” hormone. Another hormone in this part of the gland causes the production of milk in the mammary gland even in animals which have not recently had young. Pigeons can be made to secrete “milk” from their crops by this substance. If only it could be manufactured on a commercial scale the dairy industry might be transformed! MORE ENERGY NEEDED. During life our vital processes are carried on by the expenditure of a certain amount of energy. When we do work in the physiological sense, or become, “ active,” more energy has to bo rendered available. The process is rather like a car: when at rest, with the engine “ ticking over,” petrol is being burnt; some cars can be throttled down very low; others “tick over ” at a high rate. In man and the animals the throttle-opening for out “ ticking over ” is set by the thyroid gland. When the thyroid is very active the “ revs.” are speeded up,

rendering the margin for active work relatively small* as our bodies, like a car engine, have an upper limit to the " revolutions per minute,” or in terms . of (5Ur bodies, our “heart rate.” Quite recently it has beep discovered that there is a master control on the thyroid gland—another hormone which is secreted by the anterior part of the pituitary gland. Thus the general activities of the body are controlled in this indirect but extremely efficient way by the pituitary - land, acting through the thyroid. In the same laboratory in Canada where this master control of the pituitary on the thyroid gland was discovered. it has been found that the outer coat of a small gland near the kidney—the adrenal gland—degenerates when the pituitary gland is removed. An extract can be made which, without affecting any of the glands we have - discussed or interfering with

growth, causes the adrenal gland to return to its norma’ state. The outer coat of the adrenal gland is absolutely necessary to life. Disease of the gland is known and has been cured by extracts from the fresh glands ,of • oxen, pigs, or sheep. Leaving aside the question of the two possible “anti-hormones ’’discovered by Collip and his co-workers in Canada, we are faced with the difficult problem of trying to explain how a very small gland like the anterior pituitary can elaborate at least five, and possibly seven, different substances capable of the most diverse effects. At the moment no answer can be given to this question, but we hare some light on how other endocrine glands act, and it is possible that the anterior pituitary acts in a similar but not necessarily identical way. The “ honnoue ” about whose activity we know most is “ insulin.” This is, as I have pointed out, capable of saving the lives of patients affected with diabetes. Now, diabetes- is a disease which is characterised by the wastage of vast quantities of sugar. This sugar comes from the blood and, in turn, from either the sugar stores or directly from the food eaten. In the norpial person, when sweet or carbohydrate food is eaten, the sugar content of the blood is raised. As it does so, part of the brain which is very sensitive to the amount of sugar in the blood begins to send out nervous messages to the pancreas cells; which make “ insulin.” Insulin is thrown into the blood, and because of its presence the large quantities of sugar in the blood can be stored away as animal starch or glycogen in the liver, muscles, and skin. Nothing is wasted. When there is no insulin there can be no storage, and the sugar rises in the blood above the point where the kidney commenced to cast out the excess. Sugar. appears in the urine and the patient has diabetes. Here we see the phenomenon of a certain series of events called forth by a combination of chemical and nervous “messages,” a secretion of a hormone. It may be that the anterior pituitary gland hormones may be elaborated by either chemical, or nervous “ messages ” reaching it, but it is certain that the secretions of the gland are under exact control. It has been known for some time that extracts, of the posterior part of the pituitary gland cause the blood pressure to rise, some involuntary muscle tissue to contract and the sugar in the body to increase. In frogs and toads the little cells which cause the skin of the animal to appear pale or dark, as circumstances dictate, are made to expand by this extract. In the mammals, including man, the functions of this part of the gland are by no means fully understood. It has been possible to separate off the “blood-pressure raising ” hormone and to isolate the hormone which causes the contraction of involuntary muscle, but neither hormone has yet been obtained in a really pure state. Whether the other functions are under the control of other hormones i? not known. ■ There can be no doubt that this amazing little gland must be called the “ Master Gland ” of the body. Without it the' animal loses control over its chemical or internal environment to a great extent. When excessive secretion of cine or many hormones takes place bodily changes follow which often prove fatal. When one or many hormones fail a listless or sexless or helpless invalid results. As we get to know these hormones and learn of their effects it will be possible to rescue many from lives of suffering, deformity, and disease.

Believed to be the first of its kind in the world, a travelling cookery school is to set put on a tour of the Rhineland. The outfit will consist of a motor Van equipped as. a kitchen, the apparatus being capable of transference where necessary to a suitable hall. The van will be accompanied by an expert chef and a lecturer.