THE INFLUENCE OF RESERPINE ON THE NUCLEIC ACID AND ACID-SOLUBLE RIBONUCLEOTIDE CONTENTS OF INVOLUTING MAMMARY TISSUE OF RATS

(1) Changes in the content of lactose, DNAP, RNAP and acid-soluble ribonucleotides have been followed in the involuting mammary tissue of rats, and of rats treated with reserpine, for periods up to 6 days after removal of the pups.

(2) After a rise in the first 24 hr. after separation from the litter, the lactose content declines and is virtually absent after 5 days. Administration of 75 μg. reserpine a day retards the rate of this disappearance.

(3) The DNAP level falls progressively after the first 24 hr. in the normally involuting gland. Reserpine prevents this decline during the first 4 days. Seventy-two hours after weaning there is a sharp peak in the DNAP content of involuting glands from reserpine-treated rats. A similar pattern of change is found for the RNAP content.

(4) Reserpine decreases the rate of decline of acid-soluble ribonucleotides in the involuting gland, particularly of UMP, of UDP-N-acetyl-glucosamine and of those in the eluate which contains GDP and ADP-ribose.

(5) The findings are discussed in relation to the chemical changes found in involuting mammary tissue and to the histological picture presented by the gland after reserpine treatment.