17β-Estradiol inhibits 11β-hydroxysteroid dehydrogenase type 1 activity in rodent adipocytes

Abstract

17b-Estradiol (E 2 ) serves as an anti-obesity steroid; however, the mechanism underlying this effect has not been fully clarified. The effect of E 2 on adipocytes opposes that of glucocorticoids, which potentiate adipogenesis and anabolic lipid metabolism. The key to the intracellular activation of glucocorticoid in adipocytes is 11b-hydroxysteroid dehydrogenase type 1 (11b-HSD1), which catalyses the production of active glucocorticoids (cortisol in humans and corticosterone in rodents) from inactive 11-keto steroids (cortisone in humans and 11-dehydrocorticosterone in rodents). Using differentiated 3T3-L1 adipocytes, we showed that E 2 inhibited 11b-HSD1 activity. Estrogen receptor (ER) antagonists, ICI-182 780 and tamoxifen, failed to reverse this inhibition. A significant inhibitory effect of E 2 on 11b-HSD1 activity was observed within 5-10 min. Furthermore, acetylation or a-epimerization of 17-hydroxy group of E 2 attenuated the inhibitory effect on 11b-HSD1. These results indicate that the inhibition of 11b-HSD1 by E 2 depends on neither an ER-dependent route, transcriptional pathway nor nonspecific fashion. Hexose-6-phosphate dehydrogenase, which provides the cofactor NADPH for full activation of 11b-HSD1, was unaffected by E 2 . A kinetic study revealed that E 2 acted as a non-competitive inhibitor of 11b-HSD1. The inhibitory effect of E 2 on 11b-HSD1 was reproduced in adipocytes isolated from rat mesenteric fat depots. This is the first demonstration that E 2 inhibits 11b-HSD1, thereby providing a novel insight into the anti-obesity mechanism of estrogen.

Resveratrol inhibits 11β-hydroxysteroid dehydrogenase type 1 activity in rat adipose microsomes

“…In addition, these data showed that resveratrol does not inhibit G6PT, which is located in the membrane of the endoplasmic reticulum and supplies G6P to the lumen (Chou et al 2002). Further, these results were consistent with features of previous studies, indicating that no inhibition of H6PD by E 2 and 2-arylbenzofuran derivatives was observed (Tagawa et al 2009, Kiyonaga et al 2012. These characteristic properties might also be because of the typical structure of the spatial configuration of the two hydroxyl groups as observed in resveratrol, E 2 , or 2-arylbenzofuran derivatives.…”

“…Culture and differentiation of 3T3-L1 cells and microsome preparation Differentiated 3T3-L1 adipocytes and intact microsomes from mesenteric fat pads and the liver and kidney of rats were prepared according to the method described elsewhere (Tagawa et al 2009). Because it has been reported that there is no isozyme for 11b-HSD1 in liver or adipose tissue from humans and rodents, we confirmed this in this study.…”

“…Measurement of 11b-HSD1 activity 11b-HSD1 activity (11-oxoreductase) was measured using i) rat microsomes from adipose tissue (mesenteric fat depots) or liver, ii) 3T3-L1 adipocytes, and iii) rat epididymal adipose tissue according to the method previously described with minor modification (Tagawa et al 2009). Each assay was performed in duplicate or multiplicate (number of data (n): 3-5) using 10 ml microsomes, 3T3-L1 adipocytes in six-well plates, or a slice of rat epididymal adipose tissue.…”

“…Recently, we found that an endogenous steroid hormone, 17b-estradiol (E 2 ), inhibited 11b-HSD1 activity in rodent adipocytes in a non-competitive manner (Tagawa et al 2009). E 2 has phenolic and alcoholic hydroxyl groups at the C-3 and C-17b positions respectively.…”

Benzofuran Derivatives Inhibit 11β-Hydroxysteroid Dehydrogenase Type 1 Activity in Rat Adipose Tissue

“…16,17) Measurement of 11β-HSD1 Activity 11β-HSD1 activity (11-oxoreductase) was measured using microsomes from rat mesenteric fat depots, or adipocytes from 3T3-L1 according to the method described previously. 16,18) Briefly, 15 µL microsomes (1.6 mg protein/mL) were added to MOPS buffer (100 mM KCl, 20 mM NaCl, 20 mM MOPS, pH 7.4) containing NADPH (1 mM) and 11-dehydrocorticosterone (1 µM) with and without various concentrations of the test compound and the reactants were incubated at 37°C for 40 min. After extraction with dichloromethane and evaporation in vacuo, corticosterone concentrations were measured by reversed-phase semi-micro HPLC in isocratic mode (water : methanol = 45 : 55, v/v%) with UV detection.…”