Immunocytochemical identification and distribution of the cell types in the pituitary gland of <i>Bagrus bayad</i> (<i>Teleostei, Bagridae</i>)

Abstract

Immunocytochemical identification of the different cell types in the pituitary gland of Bagrus bayad was performed using antisera against mammalian (human and rat) and piscine hormones. The adenohypophysis was composed of rostral pars distalis (RPD), proximal pars distalis (PPD) and pars intermedia (PI). Prolactin and adrenocorticotrophic cells were located in the rostral pars distalis of the pituitary. Gonadotrophic and growth hormone cells were distributed in the proximal pars distalis, but gonadotrophic cells appear also at the border of the pars intermedia. Somatolactin cells, as well as alpha-melanotrophic cells were located in the pars intermedia of B. bayad pitui-tary. The prolactin (PRL) cells were distributed in the RPD stained with orange G and showed strong immunoreactivity with antiserum to chum salmon. The adrenocorticotrophic (ACTH) cells were lead hema-toxylin-positive (PbH+) and showed strong im- mu-noreactivity with anti-human ACTH; these cells bor-dered the neurohypophysis and grouped in islets be-tween PRL cells in the RPD. Growth hormone (GH) cells were densely distributed with the gonadotrophic (GTH) cells in the PPD. They were orange G positive and reacted with antiserum to chum salmon. GTH cells were located in the central area of the PPD and in the external border of the PI. These cells were Alcyan Blue and PAS positive, and immunostained with anti-chum salmon GTH Iβ and anti-chum salmon GTH IIβ. In addition, antiserum to rat thyrotropin stimulating hormone β (TSHβ) reacted positively to the GTH cells. These results suggest that GTH I, GTH II and TSH are synthesized in the same cells in the pituitary of B. bayad. The PI was composed mainly of PbH+ cells and a PAS+ cell adjacent to the neurohypophysis. The PAS+ cells from the PI bound specifically to anti-chum somatolactin. Anti-alpha- melanin stimulating hormone (MSH) stained only the PbH+ (alpha-melanotrophic) cells of the PI

Immunocytochemical identification and ontogeny of adenohypophyseal cells in a cave fish, Phreatichthys andruzzii (Cypriniformes: Cyprinidae)

“…In P. andruzzii the ir‐TSH cells were identified by antiserum against human β‐TSH and were clearly separated from GtH cells in PPD, as in other teleosts (Agulleiro et al ., ). The antiserum against human β‐TSH did not show any cross reactivity with gonadotropic cells, on the contrary of what observed in some teleosts (Nozaki et al ., ; Mousa et al ., ). In the adult some ir‐TSH cells were also found in RPD near the ir‐PRL cells, as previously reported in the grass carp Ctenopharyngodon idella (Valenciennes 1844) (Cypriniformes) (Grandi et al ., ), in A. japonica (Ueda et al ., ) and in A. anguilla (Grandi et al ., ).…”