We have the hypothalamus-anterior pituitary-endocrine axis, but is there a similar chain of command for posterior pituitary gland such that oxycotin and vasopressin are regulated by some tropic hormones?
The difference between secretion of ACTH and neurohypophysial hormones is that the prior is a two step process, with CRF from hypothalamus stimulating the anterior pituitary. The latter is produced and secreted from the same cell, only in different organs! Magnocellular neurons stretch from the hypothalamus to the posterior pituitary, where they have their neurosecretory endings packed with hormone storing large dense-core vesicles. The same neurons are osmosensitive, regulating their secretion themselves as physiological need arises. Also, they apparently do dendritic secretion as autocrine signalling. Some reading about this: http://www.ncbi.nlm.nih.gov/pubmed/24265070 and http://www.nature.com/nrn/journal/v7/n2/full/nrn1845.html Hope it helps.