236 The Vertebrate Organ Systems 



turbances are due to the reduced flow of blood through the kidney re- 

 sulting from the concentration of the blood. 



The Secretion of the Cortex. — The general name, cortin, is given 

 to the hormone of the cortex ; this secretion, however, is actually a 

 whole series of compounds. Many of these are of the type known as 

 the steroids. They are found in many seemingly unrelated sources ; 

 for example, cholesterol from the liver has a similar structure as do 

 some of the important sex hormones. One of the most important of 

 these hormones composing cortin is corticosterone. Some of these 

 hormones have been at least partially synthesized, and a rapidly in- 

 creasing number of them are becoming available for medical use. 



In addition to the many steroids (at least twenty-five) found in 

 cortin, other materials, such as carotene, cholesterol, and some fats, are 

 found. 



The Effects of Hypoactivity. — In the year 1855 an English physi- 

 cian, Thomas Addison, described a human disease which he showed to 

 be associated with atrophy of the adrenal glands. In his honor, this 

 disease became known as Addison's disease. In general, the symptoms 

 of this disease are similar to those noted as typical of the adrenal- 

 ectomized animals. These include muscular weakness, loss of appetite, 

 lowered basal metabolism, excessive elimination of sodium, fall in 

 blood sugar, kidney injury, etc. lo addition, there is accompanying 

 bronzing of the skin. 



At present some amelioration of these symptoms is afforded by use 

 of cortical extracts and a diet rich in sodium but poor in potassium. 

 For best results, it has been shown that the material corticosterone is 

 more effective than some of the other steroids found in cortin. 



The Effects of Hyperactivity. — Occasionally tumors of the cortex 

 cause excessive secretion of cortin. The effects of this are more notice- 

 able in females than in males due to the masculinization which ensues. 

 The voice lowers in pitch, hair appears on the face and is distributed 

 over the body in the typical masculine manner, and muscular develop- 

 ment is such that the bodily contours change. Relief of this condition 

 is afforded by removal of the tumors. Perhaps the explanation of 

 these seemingly unrelated response^ is to be found in the great similarity 

 of the steroids of the adrenal cortex and of the gonads. 



Occasionally cortical tumors do occur in young males, and are 

 then associated with premature development of the secondary sexual 

 characters such as beard growth, lowered voice, etc. 



