| Popis: |
1. 1) The cytochemical examination of frozen-dried preparations of the pancreas of the Rana clamitans tadpole leads to the following conclusions: 1.1. a) The zymogen granules contain a high concentration of protein, while no nucleic acid is detectable. 1.2. b) The mitochondria contain a higher concentration of protein than the surrounding cytoplasm, while the nucleic acid concentration appears to be lower. 1.3. c) The nucleolus-associated chromatin appears to show a higher ratio of PNA to DNA than other chromatic bodies of the nucleus. 2. 2) Volumetric study by the Chalkley technique indicates that the secretory process consists of the addition of the zymogen granules to an amount of ground cytoplasm that is not a function of the secretory cycle. The volumes of the nucleus and of the nucleolus are independent of the secretory stage. 3. 3) The amount per cell and concentration of cytoplasmic nucleic acid, as measured both by basic staining and ultraviolet absorption, is not correlated with the secretory cycle. 4. 4) The amount per cell and concentration of cytoplasmic protein, as measured by acid dye binding, is also independent of the secretory cycle. 5. 5) The stability of cytoplasmic nucleic acid in protein-producing gland cells of the apocrine type as contrasted with growing cells and other types of gland cells is considered to be associated with the presence of zymogen granules. These structures may function in removing synthesized protein from the site of the synthetic reaction. |
