Sex hormone binding globulin: origin, function and clinical significance

Area of Science:

• Endocrinology
• Biochemistry
• Reproductive Biology

Background:

• Sex hormone binding globulin (SHBG) is a glycoprotein that binds 17 beta-hydroxysteroid hormones like testosterone and estradiol.
• Synthesized primarily in the liver, SHBG levels are influenced by hormonal balance, thyroid hormones, insulin, and diet.
• SHBG plays a crucial role in transporting sex steroids and regulating their distribution between bound and free states in plasma.

Purpose of the Study:

• To investigate the role of SHBG in sex steroid transport and its clinical utility.
• To explore the factors affecting SHBG concentrations and their implications in various diseases.
• To evaluate the usefulness of SHBG measurement in diagnosing androgen metabolism disorders and predicting therapeutic outcomes.

Main Methods:

• Review of existing literature on SHBG synthesis, regulation, and function.
• Analysis of clinical data correlating SHBG levels with different diseases and drug effects.
• Examination of the utility of SHBG measurement and testosterone:SHBG ratios in clinical evaluation.

Main Results:

• SHBG concentrations are altered in various conditions, including hyperthyroidism, hypogonadism, androgen insensitivity, hepatic cirrhosis, myxoedema, and hyperprolactinaemia.
• Drug interactions (androgens, estrogens, thyroid hormones, anti-convulsants) can affect SHBG levels.
• SHBG measurement is valuable for evaluating mild androgen metabolism disorders and identifying women with hirsutism likely to respond to estrogen therapy.

Conclusions:

• SHBG is a critical regulator of sex steroid bioavailability.
• Abnormal SHBG levels are associated with diverse endocrine and metabolic conditions.
• SHBG measurement and related ratios provide valuable diagnostic and prognostic information in endocrinology.