Stimulation of Ribonucleic Acid Synthesis in Luteinized Rat Ovary by Cyclic 3′, 5′-Adenosine Monophosphate1

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Abstract
In luteinized rat ovarian slices [primed by human chorionic gonadotropin and pregnant mares serum gonadotropin] adenosine 3'',5''-cyclic cAMP stimulates RNA synthesis. The stimulatory effect of cAMP was observed throughout pseudopregnancy, the maximum being on day 9. The stimulatory effect of cAMP was both concentration and time dependent. Optimum concentration of cAMP was 2 mM and required a preincubation period of 30 min to elicit maximum response. The observed stimulation was not due to altered transport of [3H]uridine. The stimulatory effect of cAMP on RNA synthesis was seen both in total tissue RNA as well as RNA from microsomal fraction and was not due to altered transport of [3H]uridine. Polyacrylamide gel electrophoresis of different RNA fractions revealed that cAMP stimulated the extent of [3H] uridine incorporation into rRNA and tRNA as well as poly(A) [poly adenylic acid] containing RNA. The stimulation of precursor incorporation into poly(A) containing RNA by cAMP was confirmed by its resistance to digestion with nucleases (RNase A and RNase T1) followed by adsorption of the digest to Milliport filter, poly(U) [poly uridylic acid] coated glass fiber filters and to oligo(dT) [oligo deoxy thymidylic acid] cellulose columns. The present studies suggest that cAMP stimulates the biosynthesis of all types of RNA including poly(A) containing RNA in a nonselective manner.