A study has been made of the calcium movements in isolated acinar cells of rabbit pancreas in relation to the process of enzyme secretion. 2. After 90 min, the 45Ca2+ uptake level of the acinar cells reaches a steady state level which depends on the extracellular calcium concentration: it increases with increasing calcium concentration. 3. Carbachol, in addition to stimulating enzyme secretion, causes a decrease in the 45Ca2+ content of pre-loaded acinar cells. This decrease is virtually independent of the extracellular calcium concentration. It is followed by an uptake of 45Ca2+ which only in a medium with 2.5 mM Ca2+ leads to a significantly higher 45Ca2+ level than the steady state level. 4. Carbachol, added to acinar cells not preloaded with 45Ca2+, increases the 45Ca2+ uptake in medium with 2.5 mM and in that with 0.1 mM Ca2+. 5. The amount of enzyme released by carbachol depends on the extracellular calcium concentration: it is larger in media with higher calcium concentration. 6. It is concluded that the increase in cytoplasmic calcium concentration which takes place immediately upon addition of a stimulus and which is necessary for the stimulation of the enzyme secretion, is caused by a release of calcium from an intracellular pool and not by an influx of calcium from the extracellular medium. 7. The results suggest that there are at least three different calcium pools in the pancreatic acinar cells.
摘要
针对兔胰腺分离腺泡细胞中钙的移动与酶分泌过程的关系进行了一项研究。2. 90分钟后，腺泡细胞的45Ca2+摄取水平达到一个稳定状态水平，该水平取决于细胞外钙浓度：它随钙浓度增加而升高。3. 卡巴胆碱除了刺激酶分泌外，还会使预先加载了45Ca2+的腺泡细胞的45Ca2+含量降低。这种降低实际上与细胞外钙浓度无关。随后是45Ca2+的摄取，只有在含有2.5 mM Ca2+的培养基中，摄取后45Ca2+水平才会显著高于稳定状态水平。4. 添加到未预先加载45Ca2+的腺泡细胞中的卡巴胆碱，会增加含有2.5 mM和0.1 mM Ca2+的培养基中的45Ca2+摄取。5. 卡巴胆碱释放的酶量取决于细胞外钙浓度：在钙浓度较高的培养基中释放量更大。6. 得出的结论是，在添加刺激物后立即发生的细胞质钙浓度升高，这对于刺激酶分泌是必需的，是由细胞内钙库释放钙引起的，而不是由细胞外介质中的钙流入引起的。7. 结果表明，胰腺腺泡细胞中至少存在三种不同的钙库。
