Embryonic Development of the Pituitary Gland in the Chick

Abstract

Pituitary glands of chicken, from stages 20 (70 ∼ 72 h of incubation) to 46 (20 days) of Hamburger and Hamilton (1951), were studied by immunocytochemical and histological stainings and India ink injection into blood vessels. Using the distribution pattern of 6 types of immunoreactive adenohypophyseal cells and the location of pituitary stalk as guideposts, we found how specific areas in the epithelium of Rathke’s pouch differentiate into specific regions of the adenohypophysis at 20 days. In the sagittal plane, the walls of Rathke’s pouch were tentatively divided into the upper part (A₁ + A₂) and lower part (A₃) of the anterior wall, and the posterior wall (P₁ + P₂ + P₃). The cephalic lobe was mainly assembled by the proliferation of parenchymal cells in the areas A₂ + A₃ + P₂ of Rathke’s pouch epithelia at 3 days of incubation. The caudal lobe was derived from A₁ + P₁ + P₃. The pars tuberalis was derived from A₁ + A₂. Thus, the avian adenohypophysis is established at 13 days, though the blood supply to the pars distalis is established at 20 days. Therefore, the cephalic lobe and caudal lobe of the pars distalis and the pars tuberalis of the chicken adenohypophysis are derived from specific areas of the cell cords of Rathke’s pouch at 3 days of incubation.

Identification and characterization of a tachykinin-containing neuroendocrine organ in the commissural ganglion of the crabCancer productus

“…India ink injection into the circulatory system has long been used to map the distribution of blood vessels in neural tissue (Lane et al, 1981;Renkin et al, 1981;Renkin, 1985;Farley, 1990;Hogers et al, 1995;Murray and Wilson, 1997;Grivas et al, 2003;Sasaki et al, 2003;Cerri et al, 2004;Hutchinson and Savitzky, 2004;Marinkovic et al, 2004). Here, we developed a method using this reagent to visualize the distribution of hemolymph vessels and lacunae in the stomatogastric neuromuscular system.…”

The chicken embryo as a model for developmental endocrinology: Development of the thyrotropic, corticotropic, and somatotropic axes

“…ACTH-immunopositive cells were detected from day 7 onwards (Sasaki et al, 2003), although immunostaining with a homologous antibody to the ACTH precursor peptide pro-opiomelanocortin (POMC) showed no corticotropic cells at this age (Allaerts et al, 1999). Data on the appearance of growth hormone (GH)-and prolactin-immunoreactive cells in the chicken pituitary are again inconsistent, but most studies do show that the somatotropes and lactotropes are the last pituitary cell types to differentiate (Sasaki et al, 2003). A reverse hemolytic plaque assay (RHPA) demonstrated the absence of GH-secreting cells in pituitaries from 10-or 12-day-old embryos (Porter et al, 1995).…”

“…the use of various heterologous versus homologous antibodies with different sensitivities, differences in immunostaining protocols, the use of different chicken strains or lines, possible variation in pre-incubation history of the eggs, etc.). TSH-immunopositive cells have been reported to appear anywhere between day 4.5 and 11 of incubation (Sasaki et al, 2003;Muchow et al, 2005).…”

“…However, developmental changes in circulating hormone levels are not merely the result of the functional differentiation and growth of their respective production sites, but also of Using a homologous antibody to chicken TSH, Nakamura and colleagues (2004) found the first thyrotropic cells on embryonic day 10, but TSH mRNA -determined by RT-PCR -was expressed somewhat earlier, on day 9. ACTH-immunopositive cells were detected from day 7 onwards (Sasaki et al, 2003), although immunostaining with a homologous antibody to the ACTH precursor peptide pro-opiomelanocortin (POMC) showed no corticotropic cells at this age (Allaerts et al, 1999). …”

Expression and regulation of glucocorticoid-induced leucine zipper in the developing anterior pituitary gland

“…Initiation of hormone transcription in these cells occurs during the second half of embryogenesis and continues during early neonatal life in both mammals and birds (Japon et al 1994, Sasaki et al 2003, Ellestad et al 2006. Pituitary aGSU, POMC, and TSHb mRNAs steadily increase during the second half of embryogenesis, expression of GH, PRL, and FSHb mRNA increases most substantially during the last third of embryogenesis, and LHb mRNA is not abundant until after hatch (Ellestad et al 2006, Ellestad and Porter, unpublished).…”