II. The biliary pigment curve during the secretin test

Summary and discussion

Secretin in addition to causing an increased flow of pancreatic juice also possesses a marked choleretic effect. An intravenous injection of secretin produces an increase in flow of liver bile, estimated in our work to amount to 60 to 80 cc. during the 80 minute test period. Under normal conditions of the biliary apparatus this secretion of liver bile enters the gall bladder and is stored there, resulting in the majority of instances in a colorless duodenal juice. When, however, the function of the gall bladder is impaired, such as by occlusion of the cystic duct or when the gall bladder has been removed, this newly secreted liver bile enters directly into the duodenum and causes a marked discoloration of the pancreatic juice. By studying the icteric index curve of the different samples of duodenal juice obtained during the secretin test one can differentiate the normally functioning gall bladder from the diseased non-functioning gall bladder.

We recognize three types of biliary pigment curves. Type I is the normal curve where invariably the icteric index approximates zero either throughout the entire test or at least in the second or third samples collected; type II, the diseased and non-functioning gall bladder where the biliary pigment curve remains high in every sample collected and the icteric index varies between 30 and 50 but never dropping below 17 in our series; type III, in jaundiced individuals where the common duct is completely obstructed and the icteric index remains zero in all the specimens of the test. This helps to differentiate the obstructive from the non-obstructive jaundice as illustrated in the case of toxic hepatitis where an abundance of bile was present in the duodenal juice.

The test has been especially valuable in those doubtful cases where the gall bladder visualized poorly in the X-ray, or in some instances not at all. In four cases of our series where for some unknown reason X-ray failed to visualize the viscus the secretin test gave a normal biliary pigment curve. Subsequent X-ray examinations of these cases substantiated the secretin findings.

In borderline cases, where X-ray study with dye reveals poor concentration with faint visualization of the viscus, the secretin test helps to determine the degree of impairment of function of the gall bladder and helps to indicate the choice of therapy. The test is easily performed and can be carried out as an office procedure.

Note: We wish to thank Dr. G. Elias and Mrs. L. Schmidt for their valuable assistance in the laboratory.