Direct Cholagogues

These have been studied in fasting, curarized dogs. A cannula is inserted into the bile-duct, and is brought out of the body, the drug to be experimented upon is administered, and the amount of bile is secreted before and after the administration is noted. No food must be given during the experiment, as that alone causes a considerable increase in the biliary flow.

Direct cholagogues (the most powerful being placed first) are -

(1) Euonymus.

(2) Sodium benzoate.

(3) Sodium salicylate.

(4) Podophyllin.

(5) Iridin.

(6) Leptandra.

(7) Corrosive mercuric chloride.

(8) Sodium sulphate.

(9) Sodium phosphate.

(10) Aloes.

(11) Ipecacuanha.

(12) Diluted nitric acid.

(13) Diluted nitrohydrochloric acid.

(14) Colocynth.

(15) Colchicum.

(16) Potassium sulphate.

(17) Rhubarb.

(18) Jalap.

(19) Scammony.

(20) Diluted arsenous acid.

There are individual differences among direct cholagogues. Some, as sodium salicylate, make the flow very watery, others, as toluylendiamine, which is not given to man, make it so thick that it flows through the duct with the greatest difficulty. Euonymin, sodium benzoate, sodium salicylate, Harrogate old sulphur spring and Carlsbad water, all markedly increase both the total quantity and the solids. Podophyllin and iridin, on the other hand, increase the solids without affecting the quantity.

Indirect Cholagogues

These cause no increase in the amount of bile secreted; they act by stimulating the upper part of the jejunum and the lower part of the duodenum, thus sweeping the bile on before there is time for it to be re-absorbed.

They are - (1) Mercury; (2) most Cathartic purgatives, especially

Calomel.

Therapeutics

Cholagogues are used for cases of dyspepsia in which there is reason to believe that the liver is the organ at fault, and certainly they often have a very markedly beneficial effect. It is clearly an advantage to combine direct and indirect cholagogues in order to insure that the bile shall be excreted. As bile itself is a stimulant to the peristaltic movements of the intestine, all cholagogues are purgatives, and form a distinct class of purgatives. In cases of hepatic dyspepsia attention to diet is of the greatest importance, and muscular movements, as riding, rowing, etc., aid in the expulsion of bile from the gall-bladder and ducts.

Anti-Cholagogues

These are often called hepatic depressants. They decrease the quantity of the bile secreted. Calomel, castor oil, gamboge, magnesium sulphate, opium and lead acetate have this effect, but it is not sufficiently marked to interfere with their therapeutic use for other purposes, and they are never employed for this action.

2. Drugs modifying the glycogenic function of the liver.-We will here refer to those drugs which cause sugar to appear in the urine, and to those drugs which diminish the glycogenic function of the liver.