| Abstract: | The effects of 8-day intravenous infusions of dexamethasone on deoxyribonucleic and ribonucleic acid metabolism have been examined in the skin of the Merino sheep. In two separate experiments, depilatory doses of dexamethasone (8.4 mg kg-0.75 body weight) were shown to inhibit the 3H]thymidine incorporation into DNA in the skin by about 80%. In the presence of excess thymidine the amount of radioactivity in DNA at the end of infusion decreased to about 50% of the pretreatment values. The incorporation of 3H]uridine into RNA in the skin was not affected. Decreases in the wet weight, DNA and RNA contents of skin were observed at the end of the dexamethasone infusion. In two experiments, wool growth was reduced to 36 +/- 9% (s.e.m.) and 52 +/- 8% of the respective pretreatment values. The results suggest that the dexamethasone caused a reduction in the wool growth by inhibiting DNA biosynthesis of wool follicle cells. |
