Hypothalamic digoxin, cerebral chemical dominance, and regulation of gastrointestinal/hepatic function.

The role of the isoprenoid pathway in gastrointestinal and hepatic diseases, and its relation to hemispheric dominance, was assessed in this study. The following parameters were measured in patients with (i) acid peptic disease, (ii) ulcerative colitis, (iii) gallstones, (iv) cryptogenic cirrhosis liver, (v) Reye's syndrome, (vi) mesenteric artery occlusion, (vii) irritable bowel syndrome, and (viii) in individuals with right hemispheric, left hemispheric, and bihemispheric dominance: 1. plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; 2. tryptophan/tyrosine catabolic patterns; 3. free radical metabolism; 4. glycoconjugate metabolism; and 5. membrane composition. In patients with gastrointestinal and hepatic disease there were elevated digoxin synthesis, increased dolichol, and glycoconjugate levels, and low ubiquinone and elevated free radical levels. The RBC membrane Na(+)-K+ ATPase activity and serum magnesium were decreased. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites in the serum. There was an increase in cholesterol: phospholipid ratio and a reduction in the glycoconjugate level of RBC membrane in these groups of patients. The same biochemical patterns were obtained in individuals with right hemispheric dominance. An upregulated isoprenoid pathway and hyperdigoxinemia is characteristic of gastrointestinal and hepatic disease and in right hemispheric chemical dominance. Right hemispheric chemical dominance is important in deciding the predisposition to gastrointestinal and hepatic disease.