lg6 BIOLOGICAL CHEMISTRY 



is another internally secreting organ. The anterior portion 

 is derived from the epithelium of the nasopharynx, the pos- 

 terior portion is derived from the central nervous system, 

 and the intermediate portion is like the anterior portion 

 an outgrowth from the naso-pharynx. 



The anterior portion regulates the growth of the body. 

 Enlargement with hyperactivity leads to an overgrowth of 

 the skeleton, which in young people leads to gigantism and 

 in older people to acromegaly. The extract from the whole 

 gland was found by Oliver and Schafer to cause a rise of 

 blood pressure. * M Howell has shown this to be due to the 

 extract of the posterior lobe.f This -extract from the posterior 

 portion has an action which greatly resembles that of the 

 adrenal medulla, but differs from the latter in causing dilation 

 of the renal vessels and a flow of urine. It probably acts 

 directly on involuntary muscle and not on the sympathetic 

 nerve endings as does adrenaline. 



By histological methods Herring has traced a colloid 

 material from the intermediate portion through the posterior 

 portion to the third ventricle. This substance is probably 

 the material which is responsible for the rise of blood pressure, 

 in which case it is formed by the intermediate portion, and 

 the activity of the extract of the posterior portion is due to 

 this substance passing through it.J 



Robertson has isolated a substance which he claims is 

 the growth-promoting substance of the anterior lobe. This 

 substance he calls tethelin : it contains phosphorus, nitrogen 

 and inosite. A portion of the nitrogen is in the form of an 

 iminazolyl group. 



THE PANCREAS. 



In addition to its external secretion the pancreas 

 furnishes an internal secretion. The evidence for this 

 belief is that if the pancreas is removed the metabolism 

 of carbohydrates is upset and sugar is excreted in the urine. || 

 Cohnheim has claimed that neither muscle nor pancreas extract 

 has any glycolytic action, but that mixing extracts of the two 

 produces some substance capable of destroying sugar.^f 



* G. Oliver and E. S. Schafer, Journ. Physiol., 1895, vo1 - l8 P- 2 77- 

 f W. H. Howell, Amer. Journ. Exper. Med., 1898, vol. 3, p. 245. 

 J P. T. Herring, Quarterly Journ. Exper. Physiol., 1908, vol. i, 



p. 121. 



T. B. Robertson, Journ. Biol. Chem., 1916, vol. 24, pp. 397 and 

 409. 



|| I. v. Mering and O. Minkowski, Arch. f. exper. Path. u. Pharm., 

 1890, vol. 26, p. 371. 



Tf O. Cohnheim, Zeit. physiol. Chem., 1903, vol. 39, p. 336. 



