Rapid accumulation of vitellogenin messenger RNA during secondary estrogen stimulation of Xenopus laevis

Accurate quantitation of low concentrations of vitellogenin mRNA by hybridization to vitellogenin cDNA allows analysis of the accumulation of new vitellogenin mRNA sequences throughout secondary estrogen stimulation. Administration of a secondary injection of estradiol-17 beta to male Xenopus laevis which have been withdrawn from estrogen for 60 days results in synthesis of complete vitellogenin mRNA molecules in as little as 1 h after restimulation. Vitellogenin mRNA accumulates at a rate of 13 molecules/cell/min--at least four times the rate observed in primary estrogen stimulation and peaks at a level twice that observed in primary stimulation. Administration of estrogen to male Xenopus laevis evokes stable long lived changes in the pattern of vitellogenin gene expression and constitutes a type of cellular "memory effect."