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Doctoral thesis, 1997

Acid secretion and gastrin parameters after inhibition of acid secretion and interference with sex hormones in rats

Girma, Kinfe


Ulcer disease is today treated with drugs that profoundly and with long duration inhibit the acid secretion and such treatment is often carried out for many years. This treatment may mean a risk for the patients.
In this thesis the effects of the H+/K+-ATPase inhibitor omeprazole and the H2-receptor antagonist ranitidine are studied on acid secretion and some gastrin parameters. Both drugs inhibit basal acid secretion to a similar extent and omeprazole reduces stimulated secretion better than ranitidine. The treatment does not cause any tachyphylaxis or increased maximal secretion, but increased sensitivity to stimulation for omeprazole was seen. The total omeprazole dose can be reduced if it is given twice per day.
Fasting gradually lowers the plasma gastrin concentration as well as prolonged time between the last omeprazole dose and blood sampling. Tissue gastrin concentrations are relatively stable under these conditions.
Treatment with omeprazole and ranitidine for 28 days with doses that produce a similar 24 hour inhibition of the acid secretion increases the gastric gastrin content. Omeprazole raises the gastrin content already after 3 days and the final increase is much higher than for ranitidine. After a recovery period for 28 days, gastric concentrations are normalized.
Normal male rats secrete more acid than females in response to maximal stimulation and such daytime secretion is larger than at night. Gonadectomy reduces the acid output in males but not in females. Estradiol treatment does not influence basal acid secretion but testosterone lowers the basal acid output in females but not in males. In both sexes, estradiol and testosterone lower the stimulated daytime secretion but raise the secretion at night. Both hormones inhibits the stimulation of parietal cells in vitro.
​​​​​​​Gonadectomy lowers the number of gastrin cells and the plasma gastrin concentration in both sexes. Treatment with testosterone lowers the number of gastrin cells and the plasma gastrin concentration. Estradiol also reduces the cell number but increases the plasma gastrin concentration.

Published in

Acta Universitatis Agriculturae Sueciae. Veterinaria
1997, number: 21
ISBN: 91-576-5412-3
Publisher: Swedish University of Agricultural Sciences

Authors' information

Girma, Kinfe
Swedish University of Agricultural Sciences, Department of Animal Physiology

UKÄ Subject classification

Clinical Science

URI (permanent link to this page)