Riddle C V
Cell Tissue Res. 1985;241(3):687-9. doi: 10.1007/BF00214593.
Prekeratinized fetal epidermis may function as an osmoregulatory organ. This study shows that the structural response of fetal epidermis to cAMP (second messenger of antidiuretic hormones) is very similar to that in well characterized osmoregulatory epithelia. cAMP stimulation of unkeratinized fetal epidermis induces the appearance of "aggregates" of intramembranous particles. These aggregates are present in the apical plasma membrane of the periderm or outermost cell layer of the epidermis. Tubular vesicles that contain the presumptive aggregates fuse with the apical plasma membrane during cAMP stimulation. The same response to cAMP and to antidiuretic hormones has been reported in the osmoregulatory ion- and water-transporting epithelia of amphibian urinary bladder and mammalian collecting ducts. In these systems aggregates have been positively correlated with water transport. Thus, the fetal epidermis may control and regulate its water permeability.
角质化前的胎儿表皮可能起到渗透调节器官的作用。本研究表明，胎儿表皮对环磷酸腺苷（抗利尿激素的第二信使）的结构反应与特征明确的渗透调节上皮细胞非常相似。环磷酸腺苷刺激未角质化的胎儿表皮会诱导膜内颗粒“聚集物”的出现。这些聚集物存在于表皮的周皮或最外层细胞层的顶端质膜中。在环磷酸腺苷刺激期间，含有推测聚集物的管状小泡会与顶端质膜融合。在两栖动物膀胱和哺乳动物集合管的渗透调节离子和水运输上皮细胞中，也报道了对环磷酸腺苷和抗利尿激素的相同反应。在这些系统中，聚集物与水运输呈正相关。因此，胎儿表皮可能控制和调节其水通透性。
