Perhaps the most important of the glands is the pituitary, although disturbance of any of the glands of internal secretion is serious. The glands include the anterior and posterior pituitary, the thyroid, the pancreas, the thymus, the adrenals and the sex glands. Among the hormones that have been identified in the anterior pituitary are a growth hormone which can increase height and raise body weight.
The anterior pituitary also develops substances which pass by way of the blood to the adrenal gland, the thyroid, the sex glands and the milk-producing glands and influence their function. Recent studies have shown that the pituitary itself may be stimulated to act by adrenalinecoming from the adrenal glands and by nervous stimuli coming from the emotional center in the brain. Since so many differently acting substances are developed in the pituitary, disturbances of this gland may be reflected in the body in many different ways.
Lessened activity of the pituitary gland before a child reaches adolescence may be observed as dwarfism and subnormal mentality and sexual development. However, deficiencies of growth also result from deficient action of the thyroid gland, and instances are known in which dwarfism is hereditary. The failure of the pituitary gland may be due to deficient development or to infection or to the presence of tumors which may damage the gland. While substitute materials for the whole anterior pituitary have not yet been developed satisfactorily, some of the deficiencies can be corrected by giving thyroid, or sex gland, or adrenal cortex materials. Research has been given such a tremendous push by the discovery of Cortisone and ACTH that the outlook is more bright now than ever previously.
In the pituitary gland lies the function of creating a substance which is known as the growth hormone. This acts directly on the growth of body tissues. A dwarf is a person who is conspicuously smaller than other people of the same age and species. For normal growth a person must have proper amounts of the necessary food substances. The body takes this material and puts it into proper places as new tissue. People may be stunted in their growth from lack of essential foods or lack of oxygen. In addition, the body must develop for itself the growth hormone, thyroid hormone and sex hormone. Among other causes of dwarfism are diseases or failure of growth of bones, such as may occur with rickets.
Often children have been much smaller than others all through the period of childhood. When they pass into adolescence the body fails to make the spurt that is usual. Not only do they fail to grow in height but also they remain mentally and sexually immature. In some instances this is just a delay in action of the interlocking chain of glands that includes the pituitary, adrenal and sex glands.
The treatment of dwarfism depends on the cause. If a deficiency of essential proteins and vitamins is responsible, supply of these substances will bring about growth. Similarly, thyroid deficiency can be met by giving thyroid extract. Pituitary growth hormone has not yet been developed for general use. In many cases of delayed adolescence doctors can now prescribe certain of the sex hormones with excellent results. The determination of which to give and the time and duration of treatment must be decided for each patient according to the conditions found when the patient is studied.
If an excess of growth hormone develops in childhood before the centers from which bones grow have ceased to function, the child be comes a giant. If the excess of growth hormone comes after this time, the condition called acromegaly develops. At the beginning the giant may be strong, alert, and intelligent, but in most cases as the giant growth continues the pituitary functions lessen; then the giant becomes weak and slow. Giants naturally attract much attention. Several cases have been recorded of growth over eight feet.
Usually in acromegaly excessive glandular tissue is found in the anterior pituitary gland. Such people may have enlargements of the lungs and liver and other organs as well as general increase in growth. Acromegaly is a relatively rare condition. Attention is called to it first by the increased size of the head, hands and feet. Fatigue, headache, and muscle pain may be noticed. Among the most observed signs is the enlargement of the lower jaw. The features become larger and coarsened, the skin becomes rough and the ridges above the eyes become prominent. A voracious appetite is often noticed and sometimes is blamed for the growth changes.
Acromegaly is not a fatal condition, and many of these patients live to advanced years. Some of the people develop diabetes because of changes in the glands. Formerly, operation on the pituitary gland was recommended for most of these patients but more recently the overgrowth of glandular tissue has been found to be susceptible to the X-ray. Often exposure of the tissue to X-ray will stop the progress of the acromegaly.
Since sex-gland disturbances are frequently associated with acromegaly the provision of male or female sex hormones as needed may be most helpful. Altogether, much more may now be done for such people by giving proper amounts of the glandular substances available.
While the front portion of the pituitary gland provides a number of hormones-substances circulating in the blood-which stimulate the thyroid, the adrenals and other glands to perform their functions, the posterior or back portion of the pituitary gland has quite different effects. When injected into the body, extracts similar to those provided by the back portion of the gland act to stimulate the muscle in the walls of the intestine, the muscle of the uterus and that in the walls of the blood vessels. Hence the bowel is made active, and the blood vessels contract. Thus this substance is used to stop hemorrhages after childbirth. The substance also has a profound effect on the action of the kidneys, controlling the way in which they eliminate water. If, therefore, there is a deficiency of the substance that comes from the posterior portion of the pituitary gland, people develop a condition called diabetes insipidus in which large amounts of fluid are poured out of the body. This condition is rare; in fact, a large clinic found only about twelve such cases in 100,000 patients.
The chief symptoms of diabetes insipidus are the pouring out of great amounts of water from the body and, naturally associated with it, the taking in of tremendous quantities of water. The amounts may reach fifteen to twenty quarts a day. Because of the excess elimination of fluid, these people have a dry skin and an insatiable thirst. Under the circumstances, the condition is usually treated by giving the substance which is known as “pitressin.” Two different substances have been isolated, one of which has the power of contracting the muscle of the intestines and uterus as its chief function, and the other of which controls the elimination of fluid.