Circadian variations of blood gastrin under enteral and/or parenteral nutrition in a case of short bowel syndrome.

The study of the circadian variations of serum gastrin levels is reported in a patient after massive small bowel resection. Twenty-four hour continuous nutrition was administered intravenously, alone or with periods of enteral feeding and cimetidine. All samples of serum gastrin showed a marked elevation, 362 +/- 112 pg/ml (N less than 100 pg/ml) and a circadian rhythm was detected in all conditions except with intravenous nutrition alone. Cimetidine shifted the peak time of serum gastrin level. These results are consistent with and endogenous rhythm of serum gastrin and a chronopharmacological action of cimetidine.