Bride J
J Embryol Exp Morphol. 1978 Aug;46:21-35.
The uropygial gland (preen gland), an epidermal derivative, is a bilobed, lipid-secreting gland located over the base of the tail of most birds. In the duck embryo Anas platyrhynchos, the internal branching morphogenesis of preen gland is set up at the 17th day of incubation. Each glandular lobe is made of numerous epidermal columns each of which is terminated by a bulb or end-bud. The functional differentiation of the end-buds and the development of the cellular columns into collecting ducts were investigated. The ductal epithelium, separated from the mesoderm by a continuous basal lamina, is keratinized just as in normal embryonic avian epidermis. The features which indicate glandular differentiation in the end-buds were described. Lipogenesis results from progressive cellular differentiation characterized by proliferation and development of smooth membranes. The direct ecto-mesodermal contacts, which were observed at the end-buds after the establishment of morphogenetic pattern and before the onset of glandular secretory activity, suggest that a new interaction mechanism would be required to initiate the functional differentiation.
尾脂腺（羽脂腺）是一种表皮衍生物，是大多数鸟类尾部基部上方的双叶脂质分泌腺。在鸭胚胎绿头鸭中，羽脂腺的内部分支形态发生在孵化的第17天建立。每个腺叶由许多表皮柱组成，每个表皮柱由一个球状物或终芽终止。研究了终芽的功能分化以及细胞柱向集合管的发育。导管上皮通过连续的基膜与中胚层分离，与正常胚胎鸟类表皮一样发生角质化。描述了终芽中表明腺分化的特征。脂肪生成源于以光滑膜的增殖和发育为特征的渐进性细胞分化。在形态发生模式建立后且腺分泌活动开始前，在终芽处观察到的直接外胚层-中胚层接触表明，启动功能分化需要一种新的相互作用机制。
