The reason for this effect is not well understood and could be caused by increased absorption or reduced gastrointestinal or biliary secretion.

These pioneering studies suggested that biliary secretion might be regulated by both vagal and non-vagal neural mechanisms.

Enzymatic hydrolysis is initiated by intraluminal processes requiring gastric, pancreatic, and biliary secretions.

Yet another theory is that abnormal chloride movement out of the cell leads to dehydration of mucus, pancreatic secretions, biliary secretions, etc.

His Experiments upon the Human Bile and Reflections on the Biliary Secretions (London: 1772), was translated into several languages.

The effect of intracerebroventricular injection of neuropeptide Y on biliary secretion was studied in conscious dogs, prepared with gastric and duodenal fistulas and cerebroventricular guides.

The study concluded that UDCA-induced biliary secretion of GSNO contributed to stimulating ductal secretion of bile.

However, the alterations in biliary secretion and composition that result from ablation of the peripheral innervation of the liver suggest that central neural stimuli may indeed modulate biliary secretion.

Despite the fact that there have been many reports describing the central effects of neuropeptides on gastric and pancreatic secretion, there has been only one previous report of the effects of a centrally acting peptide on biliary secretion.

The finding by Fritz and Brooks that vagotomy abolishes the choleretic response to feeding in cholecystectomised dogs suggests that, at least as regards the digestive function of bile, neural regulation of biliary secretion may be of greater functional importance than is generally acknowledged.

Since then the gall-bladder is the part of the whole hepatic system most remote from the liver (the cause and source of biliary secretion), every instant of time bile remains in the gall-bladder, it is constantly changing from a better to a worse condition - from a living to a dying state.

However, a direct vasomotor effect of central neuropeptide Y on the nepatic artery vasculature, resulting in increased blood flow, cannot be ruled out entirely and may indeed be the mechanism causing the observed effect on biliary secretion in dogs where the arterial component to blood flow is significant as opposed to rats.