Temporal profiles of urinary excretion of NH2-terminal big gastrin immunoreactivity in humans.

We studied the temporal profile of urinary NH2-terminal big gastrin immunoreactivity (NT G-34-IR) excretion in order to evaluate the dynamics of gastrin secretion. The temporal profile of urinary NT G-34-IR excretion in normal subjects represented three peaks corresponding to each meal. In contrast, the profile in antrectomized patients and patients under total parenteral nutrition (TPN) represented a flat pattern. Urinary NT G-34-IR excretions during fasting 2-h periods in antrectomized patients and TPN patients were about one-sixth and one-third, respectively, of basal NT G-34-IR excretion in normal subjects (53.1 +/- 13.9 pmol/h). Total urinary NT G-34-IR excretion during 24 h both in antrectomized patients (220 +/- 35 pmol/24 h) and TPN patients (390 +/- 68 pmol/24 h) was also significantly lower than in normal subjects (1985 +/- 403 pmol/24 h). The present study showed that the main source of urinary NT G-34-IR is the gastric antrum, that the main factor fluctuating its excretion is food intake, and that long-term TPN reduces basal gastrin secretion. Urinary NT G-34-IR would be a useful indicator for total gastrin secretion.