Morphological and biochemical studies on the development and function of paraneurons in the branchiogenous organs

甲状腺、甲状旁腺、胸腺、腭扁桃体和后鳃体统称为产鳃器官。其中，甲状腺和甲状旁腺分别含有C细胞和主细胞。这些细胞是特定的内分泌细胞，称为甲状旁腺素，并分别分泌降钙素（CT）和甲状旁腺素（PTH），与钙（Ca）代谢有关。本研究应用免疫组织化学方法，研究了鳃生殖器内寄生虫的个体发生、维生素D（VD）摄入或Ca和VD缺乏对妊娠期Ca代谢的影响、维生素A（VA）缺乏对垂体-甲状腺和垂体-性腺系统的影响以及衰老、妊娠和冬眠期垂体内分泌细胞的形态学变化。形态测量和放射免疫分析，从形态学和生化学上揭示副神经管在鳃生器官中的发育和功能。结果表明，Ca缺乏和VD缺乏大鼠的甲状旁腺体积显著增大，VA缺乏大鼠垂体TSH细胞面积显著增大，冬眠的日本长指蝠TSH细胞面积显著减小。对鳃生器官及其附属体发育的胚胎学研究表明，甲状腺原基和后鳃体在妊娠第9天出现，甲状旁腺原基在妊娠第10天出现，后鳃体在妊娠第25天出现，后鳃体在妊娠第12天与甲状腺融合，在后鳃体的甲状腺区域出现CT免疫反应阳性细胞。

The thyroid gland, Parathyroid gland, thymus, Palatine tonsil and ultimobranchial body are collectively called branchiogenous organs. Among them, the thyroid and parathyroid glands contain C cells and chief cells, respectively. These cells are specific endocrine cells, called paraneurons, and secrete calcitonin(CT) and parathormone(PTH), respectively, to be concerned with the calcium(Ca) metabolism. In the present study, the ontogeny of paraneurons in the branchiogendus organs, the influence of vitamin D(VD) administration or Ca and VD deficiency on the Ca metabolism during gestation, the influence of vitamin A(VA) deficiency on the pituitary-thyroid and pituitary- gonadal systems, and morphological changes of the pituitary endocrine cells in the aging, gestation and hibernation are examined by immunobistochemistry, morphometry and radioimmunoassay to reveal morphologically and biochemically the development and function of parangurans in the branchiogenous organs. As the results, the morphometric analysis with image-processing system revealed statistically the remarkable increase of the volume of the parathyroid gland in the Ca- and VD- deficient rats, the significant increase of the area of TSH cells of the pituitary gland in the VA- deficient rats, and the significant decrease of the area of TSH cells in the hibernating Japanese long-fingered bats. The embryological study on the development of branchiogenous organs and their paraneurons revealed by immunohistochemistry the appearance of the primordia of the thyroid gland and ultimobranchial body on day 9 of gestation, the appearance of the primordium of the parathyroid glared on day 10.25 of gestation, the fusion of the ultimobranchial body with the thyroid gland on day 12 of gestation, and the appearance of CT-immunoreactive cells in the region of the thyroid gland derived from the ultimobranchial body.