Talmage R V, Doppelt S H, Cooper C W
Proc Soc Exp Biol Med. 1975 Sep;149(4):855-9. doi: 10.3181/00379727-149-38913.
Daily fluctuations in plasma calcium concentrations in rats trained to a closely regulated feeding pattern have been compared to corresponding plasma gastrin and calcitonin concentrations. The time period studied was that extending from 4 hr prior to the start of the feeding. Both plasma calcium and phosphate levels fedd prior to the start of the feeding period and remained low at least for the first 2 hr of feeding. This pattern was also observed in rats in which food was withheld for 2 hr past the regular feeding time. Plasma 45Ca and 32P concentrations (radionuclide injected at least one week prior to sampling) did not follow the pattern of their stable counterparts. Instead, these values rose or remained constant until after feeding had commenced, after which they fell precipitously. Both plasma calcitonin and gastrin levels rose rapidly after the start of the feeding period. The primary point of emphasis is that calcitonin secretion was produced in these rats by an intestinal related stimulus and not by a rise in plasma calcium concentration.
已将训练至进食模式受到严格调控的大鼠血浆钙浓度的每日波动情况，与相应的血浆胃泌素和降钙素浓度进行了比较。所研究的时间段是从进食开始前4小时起。在进食期开始前，血浆钙和磷酸盐水平均下降，并至少在进食的头2小时内保持较低水平。在常规进食时间过后食物被扣留2小时的大鼠中也观察到了这种模式。血浆45Ca和32P浓度（在采样前至少一周注射放射性核素）并未遵循其稳定对应物的模式。相反，这些值在进食开始前上升或保持恒定，之后急剧下降。进食期开始后，血浆降钙素和胃泌素水平均迅速升高。主要强调的一点是，这些大鼠中降钙素的分泌是由肠道相关刺激产生的，而非血浆钙浓度升高所致。
