Early development of the pituitary gland in Acipenser naccarii (Chondrostei, Acipenseriformes): an immunocytochemical study Abstract: The distribution and appearance of secretory cells in the pituitary gland were investigated for the first time in a chondrostean species, Acipenser naccarii, from embryos to juveniles, by immunohistochemistry with mammalian and teleost hormone antisera. On 5.5 day post-fertilization (2.5 days pre-hatching) the pituitary of embryos appears as an oval mass with a narrow central cavity (hypophysial cleft), close to the ventral border of diencephalon under the third ventricle. At this time, no neurohypophysis is observed, the adenohypophysis is not yet structurally divided into pars intermedia (PI) and pars distalis (PD) and only immunoreactive growth hormone cells are detectable. Seven days post-fertilization (1 day pre-hatching) the immunoreactive tireotropic cells appear in the ventral region and the immunoreactive adrenocorticotropic cells in the posterior dorsal one. At hatching, some immunoreactive melanotropic (ir-MSH) cells are visible in the posterior dorsal region and some immunoreactive prolactin cells in the anterior one. Eight days later the immunoreactive somatolactin cells appear along the posterior dorsal border and the immunoreactive gonadotropic I (ir-GtH I) cells in the ventral region. Here, a few ir-GtH II cells finally appear in 76-86 day old juveniles. The gland elongates after hatching and in 8-day old larvae two adenohypophysis regions are identified: a posterior (the presumptive PI) and an anterior one (the presumptive PD). In 156-166 day old juveniles three regions (rostral and proximal pars distalis and pars intermedia) appear and a high number of ir-MSH cells are visible in the rostral region. The first protrusion of neurohypophysis into adenohypophysis is observed in 76-86 day old juveniles and increases with age, branching into PI. The rostro-caudal distribution of the immunoreactive cells follows the spatial expression of the corresponding hormone gene families observed in zebrafish, suggesting similar differentiating mechanisms in teleosts and chondrosteans
Early development of the pituitary gland in Acipenser naccarii (Chondrostei, Acipenseriformes): an immunocytochemical study.
GRANDI, Gilberto;CHICCA, Milvia
2004
Abstract
Early development of the pituitary gland in Acipenser naccarii (Chondrostei, Acipenseriformes): an immunocytochemical study Abstract: The distribution and appearance of secretory cells in the pituitary gland were investigated for the first time in a chondrostean species, Acipenser naccarii, from embryos to juveniles, by immunohistochemistry with mammalian and teleost hormone antisera. On 5.5 day post-fertilization (2.5 days pre-hatching) the pituitary of embryos appears as an oval mass with a narrow central cavity (hypophysial cleft), close to the ventral border of diencephalon under the third ventricle. At this time, no neurohypophysis is observed, the adenohypophysis is not yet structurally divided into pars intermedia (PI) and pars distalis (PD) and only immunoreactive growth hormone cells are detectable. Seven days post-fertilization (1 day pre-hatching) the immunoreactive tireotropic cells appear in the ventral region and the immunoreactive adrenocorticotropic cells in the posterior dorsal one. At hatching, some immunoreactive melanotropic (ir-MSH) cells are visible in the posterior dorsal region and some immunoreactive prolactin cells in the anterior one. Eight days later the immunoreactive somatolactin cells appear along the posterior dorsal border and the immunoreactive gonadotropic I (ir-GtH I) cells in the ventral region. Here, a few ir-GtH II cells finally appear in 76-86 day old juveniles. The gland elongates after hatching and in 8-day old larvae two adenohypophysis regions are identified: a posterior (the presumptive PI) and an anterior one (the presumptive PD). In 156-166 day old juveniles three regions (rostral and proximal pars distalis and pars intermedia) appear and a high number of ir-MSH cells are visible in the rostral region. The first protrusion of neurohypophysis into adenohypophysis is observed in 76-86 day old juveniles and increases with age, branching into PI. The rostro-caudal distribution of the immunoreactive cells follows the spatial expression of the corresponding hormone gene families observed in zebrafish, suggesting similar differentiating mechanisms in teleosts and chondrosteansI documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
