Development of the Rabbit Pancreas with Particular Regard to the Argyrophilic Cells

Abstract

Titlbach M., E. Maňáková: Development of the Rabbit Pancreas with Particular Regard to the argyrophilic Cells. acta vet. Brno 2007, 76: 509-517.The aim of the study was the description of the prenatal development of rabbit pancreas, cell modifications, and changes in their volume and mitotic activity.immunohistochemical, light and electron microscopic procedures were employed. Stereological methods were used for estimation of cellular and nuclear volumes. hits on epithelial cells, tubular lumens, and endocrine progenitor cells were counted by systematic field sampling using test grid. Number of mitoses was registered in various cellular types after colchicine treatment. Data obtained were converted to 1 mm 3 tissue. First granules were observed in cells on day 10 and 18 hours, however two different granular types are distinguishable by electron microscopy only on day 15, when insulin and glucagon can be detected immunohistochemically. Cellular volume increased remarkably in harmony with findings of granules in serous cells. Number of epithelial cells increased also exponentially. The increase was more rapid between days 13 and 15, later it appeared exponential. value of mitotic index and length of cell cycle did not change considerably between days 15 and 24. Mitoses were observed in ductal, exocrine, as well as endocrine cells. The dividing endocrine cells were those that contained fine dense granules (progenitor cells).The sub-population of progenitor cells is able to divide, however, this source of cells appears insufficient for exponential growth. Results after colchicine treatment show the increase of cell population but the life-span and a period necessary for volume multiplication vary. Mitoses decrease in both sub-populations during the prenatal period. The progenitor cells arise probably by differentiation from the ducts, because their number increases proportionally to the main cell population.

Development of the duct system during exocrine pancreas differentiation in the grass snake Natrix natrix (Lepidosauria, Serpentes)

“…On the other hand, the smaller ducts consisted of squamous principal cells. This is similar to the embryonic pancreas of other vertebrate species (Hick et al, ; Laitio et al, ; Pictet & Rutter, ; Titlbach & Maňáková, ; Villasenor et al, ).…”

“…It can be assumed that the abundant mitotic divisions of pancreatic duct cells in Natrix are correlated with the growth of the pancreas and their tubular branching. Similar mitotic divisions were also described in the pancreatic duct cells of chick (Zeigel, ), rabbit (Titlbach & Maňáková, ), and rat (Pictet & Rutter, ) embryos.…”

“…Some of the cylindrical principal duct cells contained large bundles of elongated filaments that were oriented along the long axis of the duct cells. Similar bundles have been described in some pancreatic duct cells of toad (Kobayashi, ), rabbit (Titlbach & Maňáková, ), and mouse (Wessells & Evans, ) embryos as well as in the adult human pancreas (Kern, ; Kern & Ferner, ). It can be assumed that the role of these filaments in the embryonic pancreas of the grass snake is related to maintaining the correct shape of cells.…”

Light and Electron Microscopic Studies on Prenatal Differentiation of Exocrine Pancreas in Buffalo

“…In literature, prenatal development of exocrine pancreas has been reported in rat [ 3 ], pig [ 4 ], sheep [ 5 ], rabbit [ 6 ], and human [ 7 , 8 ], but very scanty literature is available in buffaloes [ 9 , 10 ]. So the present research work was conducted.…”

Gross Anatomical Studies on the Pancreas in Prenatal Goat (Capra hircus)

“…In the present study fused definitive pancreas was first observed at 53 days gestation. Two primordia of pancreas were fused together at 7 th week of gestation in man (Arey, 1954) and 15 th day of gestation in rabbit (Titlbach and Manakova, 2007). In goat foeti the pancreas lied in the abdominal cavity partly on right and partly on left side of median plane.…”