Steroidal Spiro-.gamma.-lactones That Inhibit 17.beta.-Hydroxysteroid Dehydrogenase Activity in Human Placental Microsomes

Abstract

The important enzyme 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) is known to regulate intracellular levels of biologically active steroids, namely, androgens and estrogens. In an effort to develop potent inhibitors of 17 beta-HSD for reducing the levels of active steroids, we found that steroidal spiro-gamma-lactones inhibit 17 beta-HSD activity. In this report, we describe the synthesis of 11 spiro-gamma-lactone analogs containing a steroidal C-18 or C-19 nucleus and compare their relative inhibitory effects on 17 beta-HSD activity in the human placenta microsomes that catalyze the interconversion of androgens and estrogens. To void the interaction of the cytosolic 17 beta-HSD activity that is specific for the interconversion of estrone and estradiol, we used 4-androstenedione as substrate. Analysis of the inhibitory effect exerted by these analogs on microsomal 17 beta-HSD activity indicates that spiro-gamma-lactones containing the C-18 nucleus are more potent inhibitors than C-19 nucleus analogs. The best inhibition was obtained with the phenolic spiro-gamma-lactone 7 (3-hydroxy-19-nor-17 alpha-pregna-1,3,5(10)-triene 21,17-carbolactone), which has an IC50 value of 0.27 microM, and was much lower than the competitive effect of the unlabeled substrate 4-androstenedione, which has an IC50 value of 1.40 microM. Preincubation with lactone 7 did not inactivate 17 beta-HSD activity. The results thus suggest that lactone 7 is a reversible in inhibitor. Lactone 7 is selective for microsomal 17 beta-HSD activity, as no inhibition was observed for cytosolic 17 beta-HSD activity.

Metabolic stability optimization and metabolite identification of 2,5-thiophene amide 17β-hydroxysteroid dehydrogenase type 2 inhibitors

“…Some steroidal [5][6][7] and non steroidal [8,9] 17β-HSD2 inhibitors are already described. In our group we also developed and reported about several classes of non-steroidal 17β-HSD2 inhibitors [10][11][12][13][14], with a strong inhibition of human 17β-hydroxysteroid dehydrogenase type 2 (h17β-HSD2) and a good selectivity toward h17β-HSD1.…”

Isolation and Structural Elucidation of Related Impurities in Canrenone

“…All solvents were of analytical grade. 1 H, 13 C, and 2D NMR spectra were recorded on Bruker-AM-400 spectrometer using TMS as internal standard. EIMS spectra were recorded on MAT-711.…”

Towards the evaluation in an animal disease model: Fluorinated 17β-HSD1 inhibitors showing strong activity towards both the human and the rat enzyme

“…[44][45][46] Recombinant mouse 17β-HSD1 and rat 17β-HSD1 were transiently expressed in HEK293 cells. Incubations were run with cytosolic fractions, tritiated E1, cofactor and inhibitor.…”