IMMUNOCYTOCHEMICAL IDENTIFICATION AND DISTRIBUTION OF THECELL'TYPESINTHEPITUITARYG~DOFTHENILEPERCH, LATES NILOTICUS (TELEOSTEl, CENTROPOMIDAE)

IMMUNOCYTOCHEMICAL IDENTIFICATION AND DISTRIBUTION OF
THECELL’TYPESINTHEPITUITARYG~DOFTHENILEPERCH,
LATES NILOTICUS (TELEOSTEl, CENTROPOMIDAE)
BY
MOSTAFA A. ·MOUSA *
•National Institute ofOceanography and FISheries – Fish Reproduction Laboratory
Key words: Immunocytochemistry, pituitary gland, Lates niloticus (Teleostei).
ABSTRACT
Immunocytochemical identijicatien of the diffirent cell types in the
pituitary gland of the Nile perch (Lates niloticus) was performed using
antisera agClinst mammalian (humCln and rat) and piscine hormones. The
cl€ien@hypophysis was cemposed ef rostral pars distalis (RPD), proximal
pars distalis (PPD) and pars intermedia (PI). Prolactin and
adrenoc@rticotrophic cells were leeated in the rostral pars distalis of the
pituitary. Gon61rietrephic and grewth hermene cells were distributed in the
proximal pars dist6dis, but gonadotr@phic cells appear also at the horder
efthe pars intermedia. Soma(fJlactin cells, as well as alpha-melanotrophic
cells were l(}cated in the pars intermedia ofLates niloticus pituitary. The
prolactin (PRL) cells were distributed in the RPD stained with orange G
and showed streng immunoreactivity with antiserum to chum salmon. The
Cldren@cfJrticotr@phic (ACTH) cells were lead hematoxylin-positive (PbJr)
and showed strong immunoreactivity with anti-human ACTH; these cells
bordered the neurohypephysis and islets between PRL cells in the RPD.
Growth hermone (GH) cells were densely distributed and associated with
the neurohypophysis in the PPD. They were orange G positive and reacted
with antiserum to chum salmon. Genadotrops were located in the central
area ef the PPD and in the external border of the PI These cells were
alcian blue and PAS positive, and immunostained with anti-chum salmon
GTH IfJ and anti-chum salmon GTH IIfJ. The gonadotrophic cells were
observed in all maturity stages ofL. niloticus. In addition, antiserum to rat
TSHf3 reacted positively to the gonadotrophic cells. These results suggest
that GTH 1, GTH 11 and TSH are synthesized in the same cells in the
pituitary ofL. niloticus. The PI was composed mainly ofPbJr cells and a
PAS- cell layer adjacent to the neurohypophysis. The PAS cells from the
PI bound speCifically to anti-chum somatolactin Anti-alpha-l’dSIJ stained
only the PbF cells (melanotrops) ofthe PI