KIDNEY 11-BETA-HSD2 IS INHIBITED BY GLYCYRRHETINIC ACID-LIKE FACTORS IN HUMAN URINE

We have previously shown that human urine contains substances that, li ke glycyrrhetinic acid, inhibit 11 beta-HSD1. We have named these subs tances ''glycyrrhetinic acid-like factors'' or GALFs. We now have foun d that human urine contains measurable quantities of both 11 beta(HSD1 )- and 11 beta(HSD2)-GALF inhibitory substances. Both are markedly ele vated in pregnancy. Their chemical and high-performance liquid chromat ography (HPLC) characteristics suggest that several of the GALFs are s teroidal. Large quantities of neutral 11 beta(HSD1)- and 11 beta(HSD2) -GALFs can be extracted directly from urine into ethyl acetate, yieldi ng fraction EA(1). Hydrolysis of the GALFs remaining in the aqueous ph ase by beta-glucuronidase markedly increases the total amounts of GALF s, with the majority now being ethyl acetate extractable (fraction EA( 2)). These EA(2) post-hydrolysis GALFs can be separated by HPLC result ing in at least six components with inhibitory activity against each i soenzyme. Only two GALF peaks are active against both 11 beta-HSD1 and 11 beta-HSD2. The others are peaks with specific 11 beta(HSD 1)- and 11 beta(HSD2)-GALF inhibitory activity. The GALFs in the same posthydr olysis EA1 extract are also inhibitory toward the 11 beta HSD1 that is present in vascular smooth muscle where they may play a role in the m echanisms controlling blood pressure. We have also found that 11 beta- HSD2 is selectively inhibited by 5 alpha-(but not by 5 beta-) reduced steroids. GC-MS analysis of the 11 beta(HSD2)-GALFs in EA(2) is now be ing performed to determine whether this group includes 3 alpha,5 alpha -ring A-tetrahydro-reduced derivatives of steroids.