Akinobu Fujita, Kimihito Tashima, Masato Nishijima and Koji Takeuchi*
Department of Pharmacology and Experimental Therapeutics, Kyoto Pharmaceutical
University, Yamashina, Kyoto 607-8414, Japan
*Corresponding author.ﾊﾊFAX:+81-75-595-4774
E-mail: takeuchi@mb.kyoto-phu.ac.jp
Abstract: We compared the acid secretory response to peptone in normal
and streptozotocin-induced diabetic rats. Animals were injected with streptozotocin
and used after 5ﾊweeks of diabetes with blood glucose levels of ﾊ>350ﾊmg/dl.
Under urethane anesthesia, 2ﾊml peptone solution (2-8%) was instilled in
the stomach through an acute fistula every 30ﾊmin. Peptone increased acid
secretion in a concentration-dependent manner in normal rats, the maximal
response being obtained at 8%. Likewise, the increased acid response was
observed in diabetic rats, yet the maximal response observed at 4% was significantly
greater than that in normal rats. In both cases, this response was inhibited
potently by famotidine as well as YM-022 (a CCKB antagonist)
and partially inhibited by atropine. Peptone increased luminal histamine
and plasma gastrin levels in both normal and diabetic rats, and the former
response was significantly greater in diabetic animals. The altered acid
secretion and histamine output in diabetic rats were reverted by insulin
treatment. Pentagastrin- but not histamine-induced acid secretion was also
increased in diabetic rats. We conclude that peptone-induced acid secretion
is increased in diabetic conditions. This phenomenon is insulin-dependent
and associated with an enhanced release of histamine but not with an increased
sensitivity of the parietal cells.
Keywords: Diabetic rat, Acid secretion, Peptone, Gastrin, Histamine
Copyrightｩ The Japanese Pharmacological Society 2000
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