| Popis: |
synopsis. With the exception ofthe agnathan fishes, a prolactin cell has been identified in all vertebrates in which it has been sought. This review examines the structure of the prolactin-producing pituitary cell in non-mammalian vertebrates, the manner in which it responds to natural and artificial stimuli, and its control by neural and humoral factors. Fundamental similarities and differences are described in an attempt to understand better its method of operation. Given our present state of knowledge, there is, among all the apparent diversity, a similarity in the basic structure and morphological response of this cell in teleosts, amphibi? ans, reptiles, and birds. One can identify and speak with relative certainty about a specific adenohypophysial cell called a "prolactin cell." More profound differences may be found at the level of control mechanisms, chemistry ofthe hormone(s), and the nature of receptivity and response of target tissues. It appears that although there are basic similarities in the design ofthe prolactin cell, the systems that control its activities may differ and the similar products produced by the cell may be used toward different ends. This review examines the structure of the prolactin-producing pituitary cell in nonmammalian vertebrates, the manner in which it responds to natural and artifically induced stimuli, and its relation to the |
