Electron microscopic observations on absorption in the epithelium of the guinea pig gall bladder
The mechanism of absorption of ThO2 particles (Thorotrast) by gall bladder epithelium was studied by taking advantage of the high electron density of the particles. Thirty min after injection into the lumen of guinea pigs, ThO2 particles were seen adhering to the apical cell surface and to the inner surface of small cytoplasmic vesicles just below the apex. The appearance suggests that the absorption occurs by pinocytosis. Two hr after the injection, ThO2 particles were widespread throughout many of the epithelial cells, and in addition to their presence in superficial vesicles, free particles were found in the lumen of vacuoles deeper in the cytoplasm. Dense cytoplasmic bodies could be seen near the Golgi apparatus and nucleus. Except for the presence of Thorotrast, the dense bodies resembled those of untreated gall bladder epithelium. Thorotrast particles were also found between adjacent epithelial cells, not only where there is a dilated intercellular space but also where the lateral cell membranes are closely apposed. No particles were seen in the terminal bar area or elsewhere outside the epithelial cells. The Thorotrast ingested by epithelial cells is apparently dealt with in one of two ways. It may be discharged into the intercellular spaces in the same way as fat in the small intestine. Alternatively, Thorotrast remains within the cell in the dense cytoplasmic bodies probably resulting from fusion of the pinocytotic vesicles and partial extraction of their contents. The dense bodies of the gall bladder epithelium resemble those of other epithelia, including the absorptive epithelium of small intestine and tracheal mucosa. Similar bodies seen in macrophages might be the end-product of phagocytosis of ThO2.
- Research Organization:
- Glasgow Univ.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-17-038731
- OSTI ID:
- 4629126
- Journal Information:
- Cell and Tissue Research, Vol. 56, Issue 2; Other Information: Orig. Receipt Date: 31-DEC-63; ISSN 0302-766X
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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