Garel J M, Besnard P, Rebut-Bonneton C
Endocrinology. 1981 Nov;109(5):1573-7. doi: 10.1210/endo-109-5-1573.
The high plasma calcitonin (CT) level found in suckling newborns and baby rats led us to hypothesize that thyroid C cells might be exhausted during the postnatal period. This prompted us to evaluate the CT concentration of the thyroid C cells during the prenatal and postnatal periods in the rat as the CT content to number ratio of C cells. The CT content of the thyroid gland increased exponentially from 17.5 (0.03 ng) to 21.5 (1.72 ng) days of gestation in the rat fetus; C cells were detected by immunofluorescence and counted from 19.5 days of gestation until term. A value of 600 + 90 C cells was obtained at 19.5 days, 1557 +/- 239 at 20.5 days, and 2602 +/- 536 at 21.5 days of gestation. Plasma CT concentrations were undetectable (less than 150 pg/ml) before 20.5 days of gestation, but increased to approximately 500 microgram/ml in 20.5- and 21.5-day-old fetuses. After birth, both the thyroid CT content and the number of C cells increased progressively. In 3-day-old suckling newborns, 4298 +/- 412 C cells were found; 9679 +/- 1114 were found 7 days after birth, and 12202 +/- 1280 were observed 15 days after birth; at the same stages, the CT contents of the thyroid gland were 6.54 +/- 0.18, 8.59 +/- 0.19, and 19.49 +/- 0.79 ng, respectively. Thus, the CT concentrations of the C cells (approximately 1.0 pg/cell) were roughly similar during the prenatal and postnatal periods in the rat. These results suggest the presence of active C cells during fetal life in the rat. They also indicate a capacity of C cells during the prenatal and postnatal periods to increase their secretion of CT while maintaining their hormone content, since the CT concentration of the C cell remains unaltered in spite of the high CT secretion in suckling rats.
在新生乳鼠和幼鼠中发现的高血浆降钙素（CT）水平使我们推测甲状腺C细胞可能在出生后时期被耗尽。这促使我们评估大鼠产前和产后时期甲状腺C细胞的CT浓度，以C细胞的CT含量与数量之比来衡量。大鼠胎儿甲状腺的CT含量从妊娠17.5天（0.03 ng）到21.5天（1.72 ng）呈指数增加；通过免疫荧光检测C细胞，并从妊娠19.5天直至足月进行计数。在妊娠19.5天获得600 + 90个C细胞的值，20.5天时为1557 +/- 239个，21.5天时为2602 +/- 536个。在妊娠20.5天之前血浆CT浓度检测不到（低于150 pg/ml），但在20.5天和21.5天龄的胎儿中增加到约500微克/ml。出生后，甲状腺CT含量和C细胞数量均逐渐增加。在3日龄的新生乳鼠中，发现4298 +/- 412个C细胞；出生7天后为9679 +/- 1114个，出生15天后为12202 +/- 1280个；在相同阶段，甲状腺的CT含量分别为6.54 +/- 0.18、8.59 +/- 0.19和19.49 +/- 0.79 ng。因此，大鼠产前和产后时期C细胞的CT浓度（约1.0 pg/细胞）大致相似。这些结果表明大鼠胎儿期存在活跃的C细胞。它们还表明产前和产后时期C细胞有能力在维持其激素含量的同时增加CT分泌，因为尽管乳鼠CT分泌量高，但C细胞的CT浓度保持不变。
