816 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



are considerably less potent than in the case of extracts of the pars nervosa. 

 The active principle of the pars intermedia, on account of these differences, 

 is looked upon by Herring 55 as representing an immature stage in the manu- 

 facture of the active principle of the gland, the final product of which is 

 represented by the extract of the posterior lobe. The fact that the cells 

 of the pars intermedia are, apparently, the ultimate source of the pituitary 

 autacoid (see page 806) supports this view. 



Clinical Manifestations of Deranged Pituitary Function 



Because of their importance from a physiological standpoint, we shall 

 now proceed to review briefly some of the more important facts that have 

 so far been brought to light by clinical observations. The pathological 

 condition most frequently observed affecting the pituitary is an adenom- 

 atous growth particularly located in the anterior lobe. Besides pro- 

 ducing general symptoms of pressure, such as diminution of the visual 

 field and, perhaps, headache, a shadow can usually be observed when the 

 patient is examined by means of the x-rays. General symptoms, com- 

 monly ascribed to a hypersecretion of the autacoid of the anterior lobe of 

 the pituitary hyperpituitarism begin sooner or later to show them- 

 selves. These symptoms are almost exactly opposite in character to those 

 observed in animals after removal of this portion of the gland. Thus, 

 the bones of the extremities become stimulated to increased growth, 

 so that if the patient is young, and the epiphyses therefore 

 not ossified, remarkable elongation of the long bones occurs, pro- 

 ducing the condition known as gigantism. On the other hand, if the dis- 

 ease does not develop until after ossification is complete, its effects be- 

 come most marked in the bones of the face, the lower jaw becoming 

 enormously hypertrophied and the supraorbital ridges very prominent. 

 The long bones also become enlarged at their extremities, and there may 

 be some increase in length of the vertebral column, although the stature 

 does not increase because of kyphosis (bowing of the spine). The 

 condition is called acromegaly. Nutritive disturbances of the skin and 

 hairs also become marked, causing the skin to become dry and yellowish, 

 and the hairs to undergo abnormal increase over the body. An early 

 symptom of the condition is a failure of the sexual power (Figs. 201 and 

 202.) 



After a time the disease begins to affect the pars intermedia et nervosa, 

 and disturbances in carbohydrate metabolism come to be observed, con- 

 sisting usually in a diminished tolerance accompanied by glycosuria, in 

 the early stages of the disease, followed by increased tolerance in the 

 later stages. The glycosuria is usually accompanied by marked polyuria. 



It should be observed that sometimes tumor of the pituitary has been 



