Estimation of Androstenedione in Human Peripheral Blood with35S-thiosemicarbazide1

Abstract

A double isotope derivative technique using ³⁵S-thiosemicarbazide and ³H indicator for estimation of androstenedione in 10 ml peripheral plasma is described. Radiochemical isolation is achieved with 2 thin layer and 2 paper chromatographic steps utilizing pyruvic acid hydrolysis for further derivative formation. With this method, plasma from ovariectomized-adrenalectomized subjects or 10 ml water blanks give values of 0.015 ±0.006 (sd) μg/100 ml. Male plasma contains 0.075 ±0.004 (se) and female plasma contains 0.145 ±0.017 (se) in the follicular phase and 0.160 ±0.010 (se) μg/100 ml in the luteal phase of the cycle (values not corrected for mean blank). Accuracy and precision studies do not indicate the presence of a systematic error. A comparison of plasma levels of both androstenedione and testosterone suggests that minimal blood testosterone is converted to blood androstenedione, but the excess concentration of androstenedione in the female could indicate that this steroid may be a major peripheral precursor of blood testosterone in the normal adult female.