Isolation and characterization of low molecular weight (4–6S) nuclear RNA in the developing rat brain, and the effect of starvation

Abstract

(1) Groups of rats were subjected to severe starvation during the development of the foetus and/or during the postnatal period. Nuclear 4–6S RNA isolated from the brains of the 4 groups of rats was studied. (2) On fractionation of the RNA on Sephadex G-100, 3 subspecies of RNA were obtained. One of them had a base composition similar to that of mouse liver t-RNA and showed amino acid acceptor activity. (3) At birth, the total amino acid acceptor activity of 4S RNA obtained from rats born of mothers on a restricted diet was about half the activity of 4S RNA obtained from rats born of mothers on a normal diet. (4) The results indicate that starvation during the development of the foetus and also during the postnatal period causes a lowering in the total body and brain weights; in the total concentration of the low molecular weight (4–6S) RNA; and in the levels of amino acid acceptor activity of 4S RNA in rat brain nuclei. The animals were not capable of returning to the normal metabolic state once damage had been caused by starvation, either during the development of the foetus or in the early postnatal period .