The Effect of Unit Gravity Sedimentation on Adrenal Steroidogenesis by Isolated Rat Glomerulosa and Fasciculata Cells*

To assess the mechanisms by which regulatory factors control aldosterone secretion, a purified adrenal glomerulosa cell system, sensitive to physiological concentrations of agonists is of critical importance. We have evaluated the feasability of using a unit gravity sedimentation technique to achieve this objective. Although basal aldosterone and corticosterone levels fell to 20% and 35% of the values in unsedimented cells, respectively, adrenal glomerulosa cells purified by unit gravity sedimentation demonstrated the same threshold sensitivity to angiotensin II (2.4 × 10−10 m) and potassium (4.3 meq/liter) as unsedimented cells. In contrast, the threshold sensitivity of the sedimented cells to α-ACTH-(l–24) (3.5 × 10−11 m) was one tenth that observed in the unsedimented glomerulosa cells. Regardless of the method of preparation, fasciculata cells did not respond to either angiotensin II or potassium, while sensitivity to ACTH was established at 3.5 × 10−12 m, and the cells reached a maximum corticosteron...