Study of the 11 β-hydroxysteroid dehydrogenase in vitro

✍ Scribed by R. Deckx; P. Moor

• Publisher: Springer
• Year: 1966
• Tongue: English
• Weight: 539 KB
• Volume: 289
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00417644

✦ Synopsis

Biochemical conditions regulating the llfi-hydroxysteroid dehydrogenase activity in spleen homogenate of mice have been studied. The conversion of ll-hydroxy-to ll-dehydrosteroids is a reversible reaction. The ratio of these compounds at equilibrium and the reaction rates depend on the pH and on the proportion between NADP and NADPtI (or NAD and NADH) in the incubation medium. Although having identical maximal reaction velocities, the conversion rate below this maximal concentration is much greater for corticosterone than for cortisol or allotetrahydrocortisol.

The llfl-hydroxysteroid dehydrogenase system is an important homeostatic mechanism in the regulation of the biological activity of corticosteroids [5]. It brings forth a reversible inactivation and a redistribution of the corticosteroids, the latter due to the fact that ll-dehydro glucocorticoids are not bound to transeortin [16].

This enzyme has been studied previously by several authors in liver, kidney, placenta, and thymus [6,10,15,17]. In the present article biochemical parameters governing the activity of this enzyme system in vitro have been studied in spleen homogenate of mice.