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A Unique Mode of A pocrine Secretion in the Gallbladder Epithelium of Clemmys japonica with a Note on the Histochemical Quality of the Secretary Material

1960; Keiji Okajima; Volume: 35; Issue: 1-3 Linguagem: Inglês

10.2535/ofaj1936.35.1-3_47

1881-1736

Kazuyorí Yamada,

Caveolin-1 and cellular processes

1. A unique mode of apo c rine secretion was observed in the epithelial cells of gallbladders from Japanese turtles (Clemmys japonica). Additionally, the histochemical quality of the secretory material was partially elucidated.2. The cycle of s e cretion representing the mode is for convenience divided into four stages; of restitution, accumulation, extrusion and cessation.3. In the f irst stage, secretory granules appear in the epithelial cytoplasm. They are morphologically classified into two types; clear granules with a figure of fine droplets and tiny spheres, and PASreactive granules of different sizes. The former develops in close association with the nucleus and mitochondria in the cytoplasm. The latter appears obviously in the Golg i apparatus of the cells. The distal extremity of the epithelial cells is provided with a narrow, homogenous strip. The two types of secretory granules migrate towards the distal end of the cells, reach this strip and mostly undergo maturation therein to turn into a lucid secretion.4. In the second stage, these secretions pass t h rough the strip and swell out, with the surface membrane covering them, into the lumen. Consequently, they present first a cap-like and then a vaultlike protrusion, and finally a secretory projection resembling in shape a club. The cross section of the secretory projection constantly reveals, regardless of the levels of sectioning, a figure perfectly identical with that of the cross section of the cell body.5. In the third stage, the secretory projection is constricted at the base, amputated at the site of constriction and then liberated as a secretory vesicle into the gallbladder cavity. Finally, the vesicle ruptures to effuse its inclusions into the surrounding media, thus becoming an amorphous secretion in the cavity.6. Following the disconnection of the secre t o ry projection, the free surface of the cells regains its flatness. Usually secretory activity pauses in the cytoplasm (The final stage).7. In the cytoplasm of the final stage, the renewal of secretory granule development begins as an initial process of the succeeding cycle of secretion.8. T h e unique mode of apocrine secretion observed here, is singular in both morphology of secretory projection and mechanism of secretion, as the following illustration indicates.9. No trustworthy speculation can be m ade of the histochemical quality of clear granules. PAS-reactive granules are believed to consist of neutral mucopolysaccharide and muco- or glycoproteins or either of the two groups, and probably of a certain type of acid mucopolysaccharide. Finally, mature, lucid secretion can not in detail be analyzed.