Age-dependent changes of uridine nucleotide and RNA metabolism in the brain of normal and hypothyroid rats.

ABSTRACT

The effects of neonatal thyroidectomy on the incorporation in vivo of labelled orotic acid into acid-soluble uridine nucleotides, nuclear RNA and microsomal RNA of the rat brain were studied at 10 and 30 days of age. It was found that the conversion of orotate into uridine nucleotides is high at the earliest stage and does not change upon maturation. At any stage, the neonatal lack of thyroid function does not effect the conversion of orotate into uridine nucleotides. Neonatal thyroidectomy led to a significant decrease in the synthesis of cerebral RNA only at 10 days after birth.