Response of rat aortic adventitial fibroblasts to oestradiol treatment in vivo. Role of the cell tubulin system.

The fine morphological response was studied of rat aortic adventitial fibroblasts to oestradiol treatment in vivo. Fibroblasts from control rats revealed a well-developed Golgi complex, rough endoplasmic reticulum and cytoplasmic microtubules. Golgi-related vacuoles, elongated and flattened rough endoplasmic reticulum cisterns and microtubules associated with both these organelles were found in these cells. In contrast, dilated rough endoplasmic reticulum cisterns mainly of the vacuolar type were a conspicuous finding in fibroblasts from oestradiol treated rats. The Golgi complex was less expressed, and these cells contained no microtubules. The cytoplasmic microtubules and/or membrane bound tubulin (rough endoplasmic reticulum cisternal membrane bound tubulin) are suggested to be the cell targets on which oestradiol exerts its primary, cholchicine-like effect, resulting in the cellular response of rat aortic adventitial fibroblasts, in a dilatation of the cisterns of rough endoplasmic reticulum.