Haynes J I
Department of Anatomical Sciences, University of Adelaide, Australia.
Anat Rec. 1999 Feb 1;254(2):269-80. doi: 10.1002/(SICI)1097-0185(19990201)254:2<269::AID-AR13>3.0.CO;2-G.
Only scant information is available in the scientific literature on the parathyroids and ultimobranchial bodies in the primitive mammals, the echidna (Tachyglossus aculeatus) and platypus (Ornithorhynchus anatinus). The major aim of this paper is to describe the morphology of the monotreme parathyroid gland and to compare it with parathyroids in mammals and reptiles. The gross anatomy and light microscopic structure of the ultimobranchial body, thymus, and thyroid are also given. Animals were dissected and routine light and electron microscopic techniques used to examine the microscopic morphology. The locations of parathyroid hormone, calcitonin and calcitonin gene-related peptide in tissue sections were identified by immunostaining. Monotremes have one pair of parathyroid glands located in the thorax and they are often associated with thymic tissue but never with the thyroid which is also present in the mediastinum. Ultimobranchial bodies are ventrolateral to the commencement of the trachea. Thymic lobules with Hassall's corpuscles are scattered in the fibrofatty tissue of the mediastinum and the ventral surface of the pericardium. Histologically, principal cells, water-clear cells, and non-secretory cells were identified in the parathyroid glands. Principal cells showed polarity and had microlamellar projections that formed intercellular canaliculi. Non-secretory cells had features similar to those of thymic epithelial reticular cells. Immunostaining of parathyroid hormone showed a diffuse distribution in parathyroid principal cells and none in ultimobranchial bodies. Identification of the ultimobranchial bodies was confirmed by immunostaining. The monotreme parathyroid gland, ultimobranchial bodies and thyroid show reptilian as well as mammalian features.
关于原始哺乳动物针鼹（短吻针鼹）和鸭嘴兽甲状旁腺及后鳃体的科学文献资料极为稀少。本文的主要目的是描述单孔目动物甲状旁腺的形态，并将其与哺乳动物和爬行动物的甲状旁腺进行比较。同时还给出了后鳃体、胸腺和甲状腺的大体解剖结构及光镜结构。对动物进行解剖，并运用常规光镜和电镜技术检查微观形态。通过免疫染色确定甲状旁腺激素、降钙素和降钙素基因相关肽在组织切片中的位置。单孔目动物有一对甲状旁腺，位于胸部，常与胸腺组织相连，但从不与也位于纵隔的甲状腺相连。后鳃体位于气管起始部的腹外侧。带有哈氏小体的胸腺小叶散在于纵隔的纤维脂肪组织和心包的腹面。组织学上，在甲状旁腺中可识别出主细胞、水样透明细胞和非分泌细胞。主细胞具有极性，有微层状突起，形成细胞间小管。非分泌细胞的特征与胸腺上皮网状细胞相似。甲状旁腺激素的免疫染色显示在甲状旁腺主细胞中呈弥漫性分布，在后鳃体中则无。后鳃体的识别通过免疫染色得以证实。单孔目动物的甲状旁腺、后鳃体和甲状腺兼具爬行动物和哺乳动物的特征。
