Mérida-Velasco J A, Sánchez-Montesinos I, Espín-Ferra J, García-García J D, Roldán-Schilling V
Department of Morphological Sciences, School of Medicine, Granada University, Spain.
Acta Anat (Basel). 1996;155(2):73-80. doi: 10.1159/000147792.
The parathyroid glands have been classically considered derivatives of the third and fourth pharyngeal pouches in most species, including humans. The presence of neural crest-derived cells in parathyroid glands connective tissue has apparently been established. However, our previous studies have provided a new hypothesis on the origin of these glands in human and chick embryos. To determine the true origin of the third parathyroid (parathyroid III) gland in the chick embryo, pieces of the third branchial arch from donor chick embryos at Hamburger and Hamilton's stage 19 (embryonic day 3) were grafted to host chick embryos at the same stage of development. Starting from Hamburger and Hamilton's stage 27 (embryonic day 5), a structure identified as the parathyroid III appeared in the ectodermal (epipharyngeal) placode of the third branchial arch graft, from which it subsequently became separated at Hamburger and Hamilton's stage 28 (embryonic day 5.5) and continued to develop and mature. Our findings suggest the conclusion that the parathyroid III gland begins to develop from the epipharyngeal placode, so that this gland, from our point of view, could be considered ectodermal in nature.
在包括人类在内的大多数物种中，甲状旁腺传统上被认为是第三和第四咽囊的衍生物。甲状旁腺结缔组织中存在神经嵴衍生细胞这一点显然已经得到证实。然而，我们之前的研究对人类和鸡胚胎中这些腺体的起源提出了一个新的假说。为了确定鸡胚胎中第三甲状旁腺（甲状旁腺III）的真正起源，将来自处于汉密尔顿和汉伯格第19期（胚胎第3天）的供体鸡胚胎的第三鳃弓组织块移植到处于相同发育阶段的宿主鸡胚胎中。从汉密尔顿和汉伯格第27期（胚胎第5天）开始，在第三鳃弓移植物的外胚层（咽上）基板中出现了一个被鉴定为甲状旁腺III的结构，在汉密尔顿和汉伯格第28期（胚胎第5.5天）它随后与之分离，并继续发育成熟。我们的研究结果表明甲状旁腺III开始于咽上基板发育，因此从我们的观点来看，这个腺体本质上可被认为是外胚层来源的。
