ISSN:
1432-119X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The distribution of 5′-nucleotidase (5′-Nase) activity is studied in esophagi of swiss mice during the following stages of the development: 14th to 18th day of gestation, newborn, 1st, 4th, 7th, 10th, 14th, 21st, and 29th day after birth, adult animals. Both light microscopical and electron microscopical methods are used. Biochemical measurements of 5′-Nase levels in esophagi of newborn and adult animals are carried out to confirm the histochemical findings. In the light microscope 5′-Nase activity is found regularly in smooth muscle cells and precursors of smooth muscle cells. The reaction product can be demonstrated in the region of the developing lamina muscularis mucosae for the first time at the 15th day of gestation. The striated muscle cells show no 5′-Nase reaction. In the basal portions of the esophageal epithelium 5′-Nase activity can be detected between the 15th day of gestation and the 29th day post partum. The maximum reaction is found during the first week after birth. In the esophageal epithelium of adult animals no 5′-Nase activity can be visualized. In the electron microscope the reaction products are found restricted to the cell membranes of epithelial cells and smooth muscle cells. Biochemical data indicate that the 5′-Nase activity per gramme protein in the esophagus of newborn animals is about 15 times higher than in the adult esophagus. These findings give strong evidence against a reverse correlation between 5′-Nase levels and proliferation capacities of tissues, which is generally assumed in the literature.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02428551
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