Anatomy of finfish and shellfish

Unit 9 - Endocrine system

9.2.1. Pituitary in teleosts
In teleosts the adenohypophysis consists of a pars intermedia and an intermediate lobe which is sometimes divisible topographically into a rostral and procentral region.This region of pars destalis appears to contain cell and the cell types characteristic of the mammalian anterior lobe .some workers have homologues the rostral pars distalis with the tetradopods pars tuberalis,but it is not certain that this is true. the neurohypophysis of teleost as in Elasmobranch is diffused and interdigites with the cells of pars intermedia and to a lesser extentwith the cells of pars distalis.Neurosecretory fibrous axons from the paraoptic nucleus and the lateral tubular nucleus terminate in all parts of neurohypophysis but their secretions have also been found in both regions of pars distalis. The Saccus vasculosus is well developed in many teleosts but it does not appear to be supplied by neurosecretory tract.