System for routine studies of steroid metabolism (prostatic 5α and 17 β dehydrogenase)

We present an original analysis system developed for routine studies of steroid metabolism in the prostate (5 α reductase, 17 β dehydrogenase), which can be easily adapted for the study of any enzymatic reaction where radiolabeled substrates are used. This system was assembled from simple commercially available components and combines the advantages of highly reproductible HPLC separation and the counting and calculation rapidity of an in-line radiodetector (FLO/ONE). The advantages of this method are: (1) access to a rapid and precise calculation of the conversion rates of an enzymatic reaction without requiring costly double label techniques; (2) limitation of nonspecific radiodecay of the tracers used (suppression of monospecific controls); (3) reduced consumption of scintillation liquid in the assay. Total automation leads to uninterrupted operation (24 hrs, a day) with reduced technical assistance and rapidity of analysis (6 samples counted and calculated hourly). The minimal operating costs of the system and the advantages it presents in comparison to a conventional procedure of TLC separation with dual labelling and non-specific phenomena controls, are discussed on the basis of the comparative results of 97 dosages carried out with the two methods