Srovnávací analýza časného vývoje a evoluce adenohypofýzy u bazálních ryb

Brezarová, Dominika

The pituitary is a master endocrine gland in the vertebrate head with many crucial roles in producing hormones and controlling secretion of other glands, and with long-standing controversies on its evolution and embryonic origin. Adenohypophysis (ADH), the front lobe of the pituitary, develops from the rostral placode that extensively migrates under the brain to connect the neurohypophysis, evagination of the ventral hypothalamus. Owing to its ectodermal placodal origin, ADH is commonly understood as a part of the vertebrate specific acquisition of our new head. Recently, however, an endodermal contribution to ADH was revealed in the teleost fish, supporting classic claims of a pre-vertebrate origin of this organ from an ancient chordate pharyngeal structure. In this work, early development of ADH was characterized in three species of basal fishes, bichirs, sturgeons, and gars, representing a possible stem-like pattern of early vertebrate craniogenesis. Interestingly, in all three species, both the early development and later migration of ADH is intimately linked with the pharyngeal domain in the rostral head. In sturgeon embryos, ADH migrates in between the brain and the pharyngeal domain, which further separates ADH from the forming mouth. In bichir embryos, ADH was additionally shown to get...

guest :: login Digital Repository
		Search		Submit		Help		About