Regulation by calcium of XXXX and @entity11249 mRNA sequences in primary cultures of rat pituitary cells.

@entity141 @entity3695 @entity10977 @entity11249
Addition of @entity141 to primary cultures of female pituitary cells incubated in serum-free medium lacking added @entity141 yielded no effects on levels of @entity3695 or @entity11249 mRNA, assayed by cytoplasmic dot hybridization. However, incubation of the cells in serum-free medium containing sufficient @entity10977 bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to reduce medium @entity141 levels below the 10-40 microM present as a trace contaminant yielded a decrease in the levels of both mRNAs. The decrease was dose-dependent at extracellular @entity141 concentrations below 1.0 microM, had an apparent half-maximum at about 0.3 microM, and did not appear to plateau with increasing incubation times. Following 2-3-day incubations of cells in low @entity141 , a reduction of @entity3695 mRNA (23-70-fold) consistently greater than the reduction of @entity11249 mRNA (9-15-fold) was observed. Similar effects of reduced extracellular @entity141 were obtained with primary cultures of male pituitary cells. The specificity of these effects of lowered extracellular @entity141 was demonstrated by the following observations. The decreases in these mRNAs were substantially reversible by readdition of @entity141 to the incubation medium. Reduction of extracellular @entity141 led to no detectable changes in cellular ribosomal RNA levels or over-all RNA synthesis. In male pituitary cells, the level of another metal-regulated mRNA, that for metallothionein, was not decreased by a reduction of extracellular @entity141 that caused a 40-fold decrease in levels of @entity3695 and @entity11249 mRNA. Hence, @entity141 exhibits specificity in its regulation of pituitary @entity3695 and @entity11249 gene expression.
