Hypothalamo-neurosecretory system of the femaleudsea bass, Lates calcarifer (Bloch), with specialudreference to gonadal maturation

摘要

Hypothalamus of Lates calcarifer (Family : Centropomidae) consists mainlyudof nucleus preopticus (NPO), nucleus lateralis tuberis (NLT) and their axonaludtracts. NPO is a paired structure situated on either side of the third ventricleudslightly above the optic chiasma. It is a highly vascularised structure andudcytoarchitecturally divisible into dorsal pars magnocellularis (PMC) comprisingudlarger neurons and ventral pars parvocellularis (PPC) with smallerudneurosecretory cells. In the hypothalamus the NLT cells were found distributeduduniformly in the infundibular floor adjacent to the pituitary stalk. Prominentudphloxine-positive neurosecretory material (NSM) was encountered in PPC ofudmatured female. Though neurosecretory cells of both NPO and NLT wereudpositive to aldehyde fuchsin (AF), acid and chrome-alum-hematoxylin-phloxineud(CAHP), cellular differentiation was more marked in the latter. Both NPO andudNLT contributed beaded axons to form the neurohypophysial tract. Herringudbodies (HB) of varying sizes were encountered in the anterior neurohypophysisud(ANH). Neurosecretory cells of both NPO and NLT exhibited fluctuations inudtheir secretory activity in response to the gonadal maturation.