The Micro Estimation of Steroids Produced by Rat Adrenals in Vitro¹

RAT adrenal glands have been found by Saffran, Grad, and Bayliss (1952) to produce steroids when incubated in a saline medium and to be stimulated to form much larger amounts when ACTH is added to the medium. Others have shown that slices of pig and beef adrenal cortex(Haynes, Savard, and Dorfman, 1952) can be similarly stimulated by ACTH. The methods used in these latter studies for extraction and purification of the steroidal material prior to estimation have involved much manipulation of the samples with attendant losses of material. The methods described here are rapid and quantitative. The ultraviolet absorption method for measuring the steroids, used by Saffran et al. (1952) and Saffran and Bayliss (1953) has been improved and adapted to the measurement of 2 to 5 μg. of steroid with an error of less than ± 10%. A second method, making use of a derivative of triphenyl tetrazolium chloride