Cell specific effect of ecdysone on RNA synthesis in the differentiated salivary gland of Acricotopus lucidus.

The influence of the steroid hormone ecdysone on the RNA metabolism of 2 cell types (main and anterior lobe) of the Acricotopus salivary gland has been investigated. Ecdysone has been found to increase the synthesis of 4S RNA and poly(A)+ RNA in the main lobe, while the anterior lobe remained unaffected by the same treatement. The stimulated poly(A)+ RNA is characterized by its relatively low cytoplasmic turnover. No evidence has been found for the stimulation of ribosomal RNA synthesis in both cell types. Analysis of the metabolic stability of cytoplasmic poly(A)+ RNA after ecdysone administration revealed a different response of the main and anterior lobe cells. Only in the anterior lobe ecdysone causes a shortening of the lifetime of that part of poly(A)+ RNA which is peculiar in its early appearance and relatively low stability in the cytoplasm.