This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Until recently it was assumed that all these drugs acted on the liver, probably by increasing the amount of sugar made from the hepatic store of glycogen; but now we have reasons for thinking that sometimes the pancreas may be the organ at fault in diabetes, for its excision causes sugar to appear in the urine, and other symptoms of diabetes; also it has been suggested that perhaps some perversion of processes going on in muscles may cause diabetes, therefore it is rash to assume that all drugs causing sugar to appear in the urine (glycosuria) must act on the liver. What little can be stated as to the mode of action of these drugs will be given when each individual drug is considered.
The drugs stated to cause glycosuria have already been mentioned (See p. 70).
Phosphorus, arsenic, and antimony diminish and even stop the formation of glycogen by the liver; they also cause fatty degeneration of it. In certain forms of diabetes, opium, morphine, and codeine have a most marked effect in diminishing the quantity of sugar in the urine.
3. Drugs modifying the formation of urea by the liver. - It is believed that some of the nitrogenous substances, especially leucin, arriving at the liver, are there converted into urea. The quantity of urea excreted by the urine is increased by phosphorus, arsenic, antimony, ammonium chloride, and iron. Phosphorus may also lead to the appearance in the urine of leucin and tyro-sin. There is some evidence that this drug causes an increase of the urea through its action on the liver, for in phosphorus poisoning that organ undergoes extreme fatty degeneration, and jaundice supervenes. Whether the other drugs act through the liver is doubtful. Antimony and arsenic, if given in large doses for some time, both produce general fatty degeneration. All these substances must be administered in almost poisonous doses in order to increase the urea in the urine, and they are not employed therapeutically for this purpose.