11HSD

11HSD refers to the enzyme 11 beta-hydroxysteroid dehydrogenase. This enzyme plays a crucial role in the regulation of steroid hormone action, particularly in the activation and inactivation of glucocorticoids and mineralocorticoids. There are two main isoforms, type 1 (11βHSD1) and type 2 (11βHSD2), which exhibit distinct tissue distributions and substrate specificities.

11βHSD1 primarily functions in regenerating active glucocorticoids from their inactive metabolites, such as cortisol from cortisone. This isoform is highly expressed in metabolically active tissues like the liver, adipose tissue, and brain. Its activity is critical for local glucocorticoid signaling and is implicated in conditions such as metabolic syndrome, obesity, and type 2 diabetes.

In contrast, 11βHSD2 is mainly involved in inactivating active glucocorticoids. It converts cortisol to cortisone, thereby protecting mineralocorticoid receptors from being activated by cortisol. This isoform is predominantly found in mineralocorticoid target tissues like the kidney, colon, and salivary glands. Dysregulation of 11βHSD2 can lead to conditions like apparent mineralocorticoid excess syndrome, characterized by hypertension and hypokalemia.

The two isoforms are encoded by separate genes, HSD11B1 and HSD11B2, respectively. Research into 11HSD enzymes continues to shed light on their diverse physiological roles and their potential as therapeutic targets for a range of diseases.