Persson P, Gagnemo-Persson R, Orberg J, Chen D, Håkanson R
Department of Pharmacology, University of Lund, Sweden.
Endocrinology. 1991 Sep;129(3):1162-6. doi: 10.1210/endo-129-3-1162.
As in the rat, gastrin and an extract of the acid-producing part of the stomach (proventriculus) were found to lower the blood Ca2+ concentration in the chicken. Furthermore, gastrin enhanced the uptake of 45Ca into the femur. It has been suggested previously that gastrin causes hypocalcemia in the rat by releasing gastrocalcin, a hypothetical hormone thought to reside in the acid-producing part of the stomach. The results of the present study in the chicken are in agreement with this concept. Not only exogenous, but also endogenous gastrin lowered blood calcium levels. Thus, the serum gastrin concentration was increased in response to ranitidine-evoked blockade of the gastric acid output; the rise in gastrin was associated with a transient drop in blood calcium. Also, food intake produced a rise in the serum gastrin concentration and a transient drop in blood calcium. However, injection of ranitidine or food intake in proventriclectomized (acid-producing part of the stomach extirpated) chickens failed to lower blood calcium, supporting the view that the gastrin-evoked hypocalcemia depends upon an agent in the gastric (proventriculus) mucosa. We suggest that endogenous and exogenous gastrin evoke hypocalcemia in the chicken by the same mechanism as that which has been postulated in the rat, i.e. by mobilization of the candidate hormone gastrocalcin from endocrine cells in the acid-producing gastric mucosa.
与大鼠的情况一样，发现胃泌素和胃产酸部分（前胃）的提取物可降低鸡的血钙浓度。此外，胃泌素可增强45Ca向股骨的摄取。此前有研究表明，胃泌素通过释放胃钙素导致大鼠低钙血症，胃钙素是一种被认为存在于胃产酸部分的假想激素。本研究在鸡身上得到的结果与这一概念相符。不仅外源性胃泌素，内源性胃泌素也会降低血钙水平。因此，雷尼替丁引起胃酸分泌受抑制时，血清胃泌素浓度会升高；胃泌素升高与血钙短暂下降有关。同样，进食会使血清胃泌素浓度升高，血钙短暂下降。然而，给切除前胃（胃产酸部分被切除）的鸡注射雷尼替丁或喂食并不能降低血钙，这支持了胃泌素引起的低钙血症取决于胃（前胃）黏膜中一种物质的观点。我们认为，内源性和外源性胃泌素引起鸡低钙血症的机制与大鼠中推测的机制相同，即通过从胃产酸黏膜中的内分泌细胞中动员候选激素胃钙素。
