The effect of zinc deficiency on the timing of deoxyribonucleic acid synthesis in regenerating rat liver

Abstract

The effect of a short-term (3-day) dietary zinc deficiency on DNA synthesis in regenerating rat liver was investigated, with particular attention being paid to the timing of the S-phase of synthesis. The findings indicated a significantly reduced (P<0,01) incorporation of 'H-thymidine into the DNA of animals receiving the zinc-deficient ration (0,3 µg/g) when compared with control animals which received 60 µg/g in their diet. Of special interest was the finding that a shift occurred in the timing of the peak of maximum incorporation, from 17½ hours postoperatively in the control animals to 25 hours postoperatively in the deficient animals. Thus, when comparisons were made between the incorporation data at the respective peaks of maximum DNA synthesis, the effect of zinc deficiency was considerably reduced (P<0,05), but not eliminated when compared with the data obtained at the same time postoperatively in both groups. The data highlight the need for studies concerning the effect of zinc deficiency on the incorporation of 'Hthymidine to be performed at the peak of maximum DNA synthesis for the respective treatments, and not, as is done at present, at the same time for all groups.

S. Afr. Med. J., 48, 1697 (1974).