Croonian lecture.—The functions of the pituitary body

Abstract

The observation of P. Marie (1885) that the disease to which he has given the name "acromegaly" is associated with tumours of the pituitary body has caused this organ to attract the recent attention of pathologists to a greater degree than any other of the structures which were formerly classed together under the generic name "ductless glands." Since Marie's description of that disease, very many cases have been recorded, and in most of these the same association has been noticed. The most striking sign of acromegaly is the increased growth of certain parts of the skeleton, especially the lower jaw and the extremities of the limbs, with hypertrophy of the connective tissue; indeed, the enlargement of the hands and feet is frequently the first change which calls attention to the existence of the disease, the patient finding that his gloves boots are becoming too small for him. In the later stages there is dorsal kyphoscoliosis. Headache is a prominent symptom, polyuria is often present, and the eyesight is frequently affected. Acromegaly usually occurs in adults, often about middle age, although it may begin during adolescence. An allied affection—(pathological) gigantism—which occurs before normal growth is completed, is accompanied, in addition to many of the above symptoms, by an increase in length both of the limb bones and of the trunk, so that the patient affected attains an altogether unusual stature. This also has been found in most cases that have been examined to be associated with tumours of the pituitary body and a concomitant enlargement of the sella turcica. It is probably the case that the changes in the skeleton in acromegaly and gigantism are due to the same cause, operating, perhaps, at different stages during the progress of growth, and that this cause is to be found in an alteration in the functions of the pituitary body. Assuming from what is known of the above diseases that the functions of this organ, or of a part of it, have to do with the growth and nutrition of the skeletal tissues, it has still to be decided whether the increased and abnormal growth which is met with in them is due to diminution or excess of the activity of the gland. The former view was taken by Marie, who noticed—as others have done since—that the nature of the tumour which is found after death is often such as to have produced complete destruction of the organ, a cancerous or sarcomatous formation having been frequently described. Those who uphold this view look upon the gland as in some way—probably by means of an internal secretion or hormone—regulating the growth of the skeleton, which in the absence of such regulation proceeds abnormally. But the opposite view (Tamburini, 1894, and Woods-Hutchinson, 1894) has also been advocated, viz., that the symptoms of acromegaly and of gigantism are due to a hypertrophic condition of the pituitary, or, according to the very probable suggestion of Woods-Hutchinson, of its anterior lobe alone, which may be considered to produce too great a quantity of a hormone which stimulates bone-growth. The most important argument in favour of this view is derived from the fact that the pituitary tumours which have been found to be associated with the acromegalic condition have in many instances, especially where the tumour has not been unusually large, been described as a simple glandular hyperplasia of the anterior lobe. And in a few cases of acromegaly which have been noted to be unaccompanied by any distinct enlargement of the pituitary, the glandular cells have been described as unusually full of the granules which are generally regarded as indicative of the secretory activity of the cells.