Immunocytochemical and in situ hybridization studies of gastrin after cisplatin treatment

Cisplatin treatment (9 mg/kg) causes bloating of the stomach, an increase i n gastric acid, and ulceration in rats. Gastrin, a gut peptide, plays an im portant role in regulating gastric acid production. To study the role of ga strin in this increased gastric acid production after cisplatin treatment, male Wistar rats (100-150 g) were treated with cisplatin (9 mg/kg) in five divided doses over 5 consecutive days. The rats were sacrificed 1, 6, 10, o r 15 days after the last treatment. As measured by immunocytochemistry, in situ hybridization, Northern blot, and dot-blot techniques, gastrin was fou nd to be below detectable limits just 1 day after cisplatin treatment. Howe ver, 10-15 days after the last injection, the levels for both gastrin and i ts mRNA gradually recovered to normal. Northern blot studies showed that de creased somatostatin mRNA parallels the changes of gastrin and its mRNA. Th ese results suggest that after cisplatin treatment the increased gastric ac id production in rat stomach is independent of gastrin. This decrease of ga strin production is not under the influence of somatostatin, which also dec reased after cisplatin treatment.