ISSN:
1432-0878
Keywords:
Gallbladder epithelium
;
Brush border
;
Apocrine secretion
;
Ultrastructure
;
Teleosts
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The free surface of the epithelial cells in the gallbladder of the rainbow trout (a predatory fish) and the tench (an omnivorous fish) is characterized by well-developed microvilli. They are irregularly arranged in the tench, but form a true brush border consisting of regularly aligned microvilli in the rainbow trout. In both species membrane-bounded cytoplasmic protrusions, up to 5 μm in diameter, extend from the apical surface. These protrusions are free of granules, secretory vesicles or other organelles; only in the tench some of them contain glycogen. Thus, the previously used terms “apocrine and droplet secretion” are not justified; the epithelial protrusions are now to be regarded as droplets of degenerated cytoplasm. Since they resemble the protrusions reported in fetal and postnatal epithelial cells in the gallbladder of higher vertebrates, interspecific differences are discussed. There is no significant correlation between the seasonal activity of the fish and the abundance or structure of the cytoplasmic protrusions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00216886
