| Abstrakt: |
The synthesis of proteins, as indicated by the incorporation of triatiated leucine into trichloroacetic acid-insoluble material, was studied in vivoin the rat parotid gland. In a series of preliminary studies, it was shown that in the rat parotid gland most of the incorporated label was used for the synthesis of secretory materials. In animals fed solid chow there was a diurnal variation in the rate of synthesis. During the day, as the gland stores of zymogen granule materials increased, synthesis decreased. Conversely, during the night, as these stores of secretory products were expelled, synthesis increased. If solid chow was replaced by liquid chow, secretion was not stimulated, the gland became atrophic, and the gland stores of secretory products were reduced to low levels. Synthesis also decreased to a stable level equivalent to 50% of the initial 8 a.m. level; no diurnal pattern was seen. If animals were then refed solid chow, synthesis was increased to normal levels. It was concluded that, in addition to stimulating secretion, mastication also plays a role in regulating the synthesis of the secretory products. |
