The plasma-
gastrin response to feeding and to
insulin stimulation was determined before and after precise antrectomy in conscious rhesus monkeys (Macaca mulatta). Feeding resulted in a significant increase above basal
gastrin levels (107 plus or minus 13 to 276 plus or minus 22 pg. per milliliter), as did stimulation with
insulin (93 plus or minus 8 to 182 plus or minus 23 pg. per milliliter). Antrectomy reduced basal
gastrin concentrations and abolished the
gastrin response to both feeding and
insulin. Antrectomy abolished the
acid secretory response to
histamine and
insulin. In order to eliminate the problems of reflux
gastritis and to study the time course of reduced
acid secretory capacity, three monkeys were antrectomized and maintained by duodenal feedings. The
histamine acid secretory response virtually was abolished within 24 hours and was not recovered over a 4 week period. Parietal cell architecture remained intact. In the monkey a major portion of basal circulating
gastrin is
antral in origin and the
gastrin response to feeding and
insulin is from the antrum exclusively. Loss of
antral gastrin results in a virtual abolition of the
acid secretory response to
insulin and
histamine. This decline is immediate in onset and is not related to parietal cell
atrophy.