1042 ABSORPTION 



The Regulation of the Sugar Supply of the Body. — The sugar con- 

 tent of the blood of the general circulatory system is determined by 

 two factors, namely, by the production of glucose by the liver (glyco- 

 genolysis), and by the consumption of this substance by the tissues 

 (glycolysis). Both these processes are in turn dependent upon an 

 adequate conversion of the absorbed sugar into glycogen (glycogenesis). 

 Consequently, it may be said that the sugar content of the body is 

 the result of an interaction between these three factors, and that such 

 conditions as hyperglycemia and glycosuria are the outcome of a dis- 

 turbance in any one or several of these processes.^ Under normal 

 conditions, a harmonious interaction between these factors may be 

 brought about through the nervous system or through chemical agents 

 contained in the blood stream. Regarding the nervous control we 

 have the positive evidence of CI. Bernard that a puncture of the floor 

 of the fourth ventricle (rabbits) is usually followed by an excessive 

 secretion of urine, containing abnormally large amounts of sugar 

 (glycosuria). This has led to the assumption that the aforesaid ac- 

 tivities are under the control of a special center which is often referred 

 to as the glycogenic or diabetic center. 



It has been shown that the stimulation of either the greater splanch- 

 nic nerves or the hepatic plexus gives rise to glycosuria, the claim 

 being made that these nerves are concerned with the storage and con- 

 version of glycogen by the cells of the liver. It is held further that 

 this regulation is under the control of a hormone secreted by the 

 adrenal glands, but the evidence so far presented in support of this 

 contention, is not at all convincing. In spite of this fact, however, it 

 cannot be doubted that glycosuria is frequently associated with mental 

 excitement. Furthermore, the disease of diabetes mellitus usually 

 affects persons with neurotic tendencies or those who are under a 

 constant and severe mental strain, or whose work demands much 

 mental concentration and exactitude. ^ At present, however, no 

 facts are at hand to show that diabetes mellitus finds its initial cause 

 in an outpouring of adrenin in consequence of too frequently repeated 

 emotions, such as anger, fear and fright.^ 



The control of the formation and consumption of the sugars by 

 hormones may be discussed at this time in a very brief manner, because 

 this subject matter has already been dealt with in a preceding chap- 

 ter. McLeod^ states that this regulation may arise in consequence of 

 (a) the concentration of the glucose in the blood, (6) the presence in 

 the blood of the products of decomposition of the glucose, and (c) the 

 action of some internal secretion. In accordance with this investi- 

 gator, the first possibility is based upon the law of mass action, in 



1 McLeod, Physiol, and Biochem. in Modern Medicine, C. V. Mosby, St. Louis, 

 1918; and Hewlett, Monogr. Med., Appleton and Co., 1917. 



2 Cannon, Bodily Changes in Pain, Hunger, Fear and Rage, Appleton and Co., 

 1915. 



3 Allen, Glycosuria and Diabetes, Boston, 1913; also: Von Noorden, Metabolism 

 and Pract. Medicine, Chicago, 1907. 



