Axon guidance effects of classical morphogens Shh and BMP7 in the hypothalamo-pituitary system.

The hypothalamus plays a key role in homeostasis. Many of its effector functions are mediated through neuroendocrine neurons whose axons project to the median eminence or posterior pituitary. Understanding the guidance of hypothalamic neuroendocrine axons in development therefore adds important insight into hypothalamic function. Previous studies show that FGF10 deriving from the medial ventral midline of the hypothalamus plays an important role in attracting developing neuroendocrine axons. Here we show that Shh and BMP7, which are expressed in the anterior and posterior hypothalamic ventral midline respectively, together repel hypothalamic axons towards the medial ventral midline.