208 ESSENTIALS OF ZOOLOGY 



regulates the rate of sugar production by the liver, and promotes 

 the storage of sugar as glycogen in the muscles. It therefore de- 

 creases the amount of sugar in the blood. 



Extracts of insulin are obtained from the pancreas of animals and 

 are used commercially for the treatment of the condition known as 

 diabetes. This disorder is due to a disturbance of the metabolism 

 of sugars, provoked by a deficiency of insulin. The blood contains 

 too great a percentage of sugar, but this is not turned into needed 

 energy, and much water is excreted by the kidneys in order to elimi- 

 nate the excess sugar. The patient suffers, therefore, from fatigue, 

 excessive hunger, and thirst. The injection of insulin subcutane- 

 ously assists in regulating the condition by restoring the power to 

 transform glucose into glycogen in the muscles. The patient re- 

 gains strength and weight as a result, but the treatment does not 

 perfect a complete cure and additional insulin must be injected at 

 intervals to maintain normal health. Overdoses of insulin result in 

 very serious disturbances, which may be relieved by ingestion of 

 glucose. 



Among the functions of the hormone, adrenalin, is the accelera- 

 tion of the production of glucose in the blood ; it is apparent, there- 

 fore, that the hormones, insulin and adrenalin, are antagonistic in 

 their effect on sugar metabolism, and an upset of the normal pro- 

 duction of these secretions results in metabolic disturbances. 



Thus we see the complexity of the performance of these secre- 

 tions in the body. When they are present in correct proportions, 

 the organism enjoys a smooth functioning of its physiological proc- 

 esses, regulated by the hormones. The malfunctioning of any one 

 endocrine organ results, however, in a disturbance of those processes 

 which it specifically regulates and usually of others which it influ- 

 ences in conjunction with its sister glands of internal secretions 

 or with other regulatory organs of the body. Each gland is called 

 upon, therefore, to function in full cooperation with the other glands 

 as well as to perform duties peculiar to itself. 



References 



Allen, Edgar: Sex and Internal Secretions, Baltimore, 1939, Williams and Wilkins 



Company. 

 Cameron, Alex. T.: Recent Advances in Endocrinology, Philadelphia, 1936, P. 



Blakiston's Son & Co. 

 Schafer, E. A.: The Endocrine Organs, ed. 2, London, 1916^ Longmans^ Green & 



Company. 



