Regulation of Protein Synthesis in Hen's oviducts. I. Removal of extracellular and intracellular proteins and their effects on protein synthesis.

The minced oviducts prepared from laying hens contained considerable amounts of extracellular proteins (about 60 mg per g of the wet oviducts), which could largely be removed (about 80%) by washing four times with chilled 5rebs-Ringer-Tris buffer, pH 7.6. When the washed, minced oviducts were incubated at 37 degrees with the buffer, intracellular proteins were increasingly secreted to the extracellular fluids as the incubation time was increased and the amounts of intracellular proteins decreased concomitatnly, suggesting that the rate of secretion of intracellular proteins was faster than that of protein synthesis under the conditions used (without addition of amino acids to the medium). Repeated 5-min incubations (five to seven times) resulted in the secretion of intracellular proteins in amounts of 100 mg or more per g of the wet oviducts. The secretion rate of intracellular proteins was almost constant at 77 degrees regardless of the volume of buffer used for the incubation, and no secretion occurred at 4 degrees even after 5 h. It appeared that a 30 min period was required for the secretion of intracellular proteins from the oviducts at 37 degrees and that the rate of secretion was not affected appreciably by the amount of secreted proteins present in the extracellular fluids. The protein synthesis activity in the washed, preincubated minced oviducts was independent of the amount of intracellular proteins involved but was dependent upon that of secreted proteins present in the extracellular fluids.