Blumen G, Merzel J
J Biol Buccale. 1982 Mar;10(1):73-83.
Eight mice (M. musculus, albinus), two hours old, were sacrificed from 1 to 168 hours following the administration of a single dose of 1 microCi/g body weight of 3H-Thymidine. An other group of six mice received a single dose of 5 microCi/g body weight of 3H-Proline and the animals were killed from 20 min. to 120 h after the injection. The unfixed hemi-jaws containing one incisor tooth, were processed to obtain frozen cross serial sections. With time, as the tooth grows, the 3H-Thymidine labelled ameloblasts move away from the apical end of the incisor at a daily rate of 550 micrometer. By determining the silver grains content over ameloblasts and related enamel matrix in animals which received 3H-Proline, using serial sections separated from each other by 550 micrometers, it was shown that : 1) The silver grains concentration over secretory ameloblasts, which was maximum 20 min. after 3H-Proline administration, showed a decrease after 24 h and a new increase between 48 and 72 h and a further decrease at later time intervals ; 2) such second reactive peak was not observed in post-secretory ameloblasts; 3) the radioactive reaction over the enamel matrix after reaching a maximum 24 h after the injection, decreased at 48 h and another increase in radioactivity was detected at 96 h when the matrix moved incisally but was still related to secretory ameloblasts. The results were interpreted as indicative of the participation of the secretory ameloblasts in the removal of proline-containing protein, which can be considered either as one of the steps of enamel maturation, or also as evidence of a distinct process by which there would be a partial turnover of the organic matter in young enamel.
选用8只出生2小时的小白鼠（小家鼠，白化变种），在给予单剂量1微居里/克体重的³H - 胸腺嘧啶核苷后1至168小时内将其处死。另一组6只小鼠接受单剂量5微居里/克体重的³H - 脯氨酸，在注射后20分钟至120小时内将动物处死。取含一颗切牙的未固定半颌骨，制作冷冻交叉连续切片。随着时间推移，牙齿生长，³H - 胸腺嘧啶核苷标记的成釉细胞以每天550微米的速度从切牙顶端移开。通过测定接受³H - 脯氨酸的动物中，相互间隔550微米的连续切片上成釉细胞及相关釉基质上的银粒含量，结果表明：1）分泌期成釉细胞上的银粒浓度在³H - 脯氨酸给药后20分钟时最高，24小时后下降，48至72小时之间再次升高，之后的时间间隔进一步下降；2）在分泌后期成釉细胞中未观察到这种第二个反应峰；3）注射后24小时釉基质放射性反应达到最大值，48小时下降，当基质向切端移动但仍与分泌期成釉细胞相关时，96小时检测到放射性再次升高。这些结果被解释为表明分泌期成釉细胞参与含脯氨酸蛋白质的清除，这可被视为釉质成熟的步骤之一，或者也可作为年轻釉质中有机物部分更新的独特过程的证据。
