Endocrine Disruption: In Vitro Aromatase Inhibition using Human Recombinant Microsomes/Mn Metal Powder and MnCl2

The objective of this screening study was to evaluate the ability of two inorganic Mn-containing Materials (i.e. MnCl2 and Manganese metal Powder) to inhibit the catalytic activity of aromatase, the enzyme responsible for the conversion of androgens to estrogens, in vitro.

Within each experiment, the test materials were tested at eight concentrations (in triplicate) together with a complete dose-response curve of the positive control inhibitor 4-hydroxy-androstenedione (4-OH-ASDN).

Based on preliminary solubility assessments, it was decided to evaluate the test materials at 8 different concentration ranges. 

The results for the test materials were negative. The coefficient of variation (CV) for replicates within each sample type and concentration were in all cases < 15%. The lowest average point on the dose response curve was 97.9%. Since this is > 75%, the results were  considered negative in the aromatase assay.