The steroid metabolite 16(ß)-OH-androstenedione generated by CYP21A2 serves as a substrate for CYP19A1.

The 21-hydroxylase (CYP21A2) is a steroidogenic enzyme crucial for the synthesis of mineralo- and glucocorticoids. It is described to convert progesterone as well as 17-OH-progesterone, through a hydroxylation at position C21, into 11-deoxycorticosterone (DOC) and 11-deoxycortisol (RSS), respectively. In this study we unraveled CYP21A2 to have a broader steroid substrate spectrum than assumed. Utilizing a reconstituted in vitro system, consisting of purified human CYP21A2 and human cytochrome P450 reductase (CPR) we demonstrated that CYP21A2 is capable to metabolize DOC, RSS, androstenedione (A4) and testosterone (T). In addition, the conversion of A4 rendered a product whose structure was elucidated through NMR spectroscopy, showing a hydroxylation at position C16-beta. The androgenic properties of this steroid metabolite, 16(ß)-OH-androstenedione (16bOHA4), were investigated and compared with A4. Both steroid metabolites were shown to be weak agonists for the human androgen receptor. Moreover, the interaction of 16bOHA4 with the aromatase (CYP19A1) was compared to that of A4, indicating that the C16 hydroxyl group does not influence the binding with CYP19A1. In contrast, the elucidation of the kinetic parameters showed an increased Km and decreased kcat value resulting in a 2-fold decreased catalytic efficiency compared to A4. These findings were in accordance with our docking studies, revealing a similar binding conformation and distance to the heme iron of both steroids. Furthermore, the product of 16bOHA4, presumably 16-hydroxy-estrone (16bOHE1), was investigated with regard to its estrogenic activity, which was negligible compared to estradiol and estrone. Finally, 16bOHA4 was found to be present in a patient with 11-hydroxylase deficiency and in a patient with an endocrine tumor. Taken together, this study provides novel information on the steroid hormone biosynthesis and presents a new method to detect further potential relevant novel steroid metabolites.

Frequency of parenteral exposure and seroprevalence of HBV, HCV, and HIV among operation room personnel.

A study was designed to determine the frequency of needle-stick injuries, immunization status for hepatitis B virus (HBV) and sero-prevalence of HBV, hepatitis C virus (HCV), and human immunodeficiency virus (HIV) infections among operation room personnel. Self-assessment questionnaires were completed and blood tested for HBsAg, anti-HBc (total), anti-HCV and anti-HIV. Of 114 operation room personnel studied, the majority (58.8%) reported more than four needle-stick injuries per year, 36.8% one to three needle-stick injuries per year, while 4.4% reported no needle-stick injury in the last five years. Thirty-six percent of personnel had received a complete course of hepatitis B vaccination. There was serological evidence of hepatitis HBV virus and/or HCV infections in 31% of the studied population. Four percent were reactive for HCV infection, 7.5% for HBsAg infection and 25.43% for anti-HBc (total); none was HIV positive. Eighty percent of the HCV positive and 55% of the anti-HBc (total) positive personnel had more than four needle-stick injuries per year in the last five years, while 75% HBsAg-reactive personnel had received one to three needle-stick injuries per year. This study indicates a need for continued efforts to minimize the risk of blood-borne infection by enhancing the compliance of operation room personnel with HBV vaccination and adherence to infection control measures.