434 A TEXTBOOK OF PHYSIOLOGY 



appears in the urine secreted by that kidney before it appears in the 

 urine -secreted by the other kidney. If it be mixed with defibrinated 

 blood and perfused through an excised kidney, sugar is excreted. 

 No hyperglycaemia is induced, and no store of glycogen in the liver is 

 requisite. The sugar is formed in the kidney under the influence of 

 the drug. The sugar does not come from the drug itself, since phlore- 

 tin, the portion of the alkaloid which is free from dextrose, also causes 

 glycosuria. Two sources of the sugar have been suggested : (1) Glucos- 

 amine, the carbohj-drate-holding group attached to the blood-proteins ; 

 (2) amino-acids formed within the kidney itself. 



The amount of sugar is often too large to be accounted for wholly 

 by the first view. The administration, together with the drug, of 

 alaniu and other allied amino-acids causes an increased sugar excretion. 

 The nitrogen excretion of the urine is also increased by phloridzin, 

 the | ratio being 3-6 after all the hepatic glycogen has been got rid 

 of by fasting. 



5. Adrenalin Glycosuria. The fact that injection of adrenalin 

 causes glycosuria has already been mentioned. It is believed that 

 adrenalin normally aids the liver in the performance of its glycogenic 

 function (see p. 428). Injection of adrenalin apparently increases the 

 conversion of glycogen into dextrose, and thus floods the blood with 

 sugar a condition allied to puncture diabetes. Adrenalin causes 

 glycosuria in starved animals, and also in animals which have been 

 submitted to the administration of phloridzin. It is stated that 

 the administration of adrenalin in increasing doses causes a deposition 

 of glycogen in the liver, but not in the muscles, in rabbits from 

 whom all traces of glycogen had been removed both by starvation and 

 doses of strychnine. The convulsions produced by strychnine expend 

 the last of the glycogen. This internal secretion therefore plaj-s an 

 important part in the production of glycogen from sugar, of sugar 

 from gl}"cogen, and of sugar from proteins. 



6. Thyroid and Parathyroid Glycosuria. After removal of both 

 the thyroid and parathyroid glands, the organism is said to show a 

 diminished tolerance to dextrose. When the thyroids alone are re- 

 moved (see p. 515 for a discussion of the relationship of these glands to 

 each other), there is no evidence of such diminished tolerance. It 

 is necessary that the parathyroids be ako removed. The para- 

 thyroids apparently influence carbohydrate metabolism in such r, 

 way as to prevent the accumulation of excessive sugar within the 

 organism. The thyroids probably have a function which is supple- 

 mentary to the action of adrenalin. Taking away the thyroids has 

 been shown to lessen the glycosuria induced by a given dose of ad- 

 renalin. Excess of thyroid, on the other hand, possibly causes 

 glycosuria by bringing about a more marked action of adrenalin 

 (see p. .",05). 



7. Pituitary Glycosuria. It is claimed that intravenous or sub- 

 cutaneous injection of extracts of the posterior lobe of the pituitary 

 gland causes a glycosuria in animals fed on an ordinary diet, and that 

 this is due to an internal secretion which lowers the utilization of 



