Effects of different doses of estrogen on the aortic wall of young immature rabbits

Abstract

The object was to study with a light microscope the morphological changes in the aorta and the effects on spontaneous aortic arteriosclerosis produced by administering different doses of estrogens (estradiol) to animals. Seventy-seven immature New Zealand rabbits were treated and compared with 72 controls. None showed fat content in the aortic wall. The estradiol was given for a short period of 8–9 days or for 22 days. Nearly identical morphological effects were noted in all animals receiving estrogen. The reversal effect on arteriosclerosis was noted only in the group treated for the short period with a dosage of 9.7 mg/kg. Those animals given smaller or larger doses or treated for a longer period showed no reversal effect. This indicates that the reversal effect is the product of metabolic changes not understood at this time. Further studies, including enzymatic studies, must be performed before we can discover what metabolic processes are responsible for the vavorable arteriosclerotic reversal effect.