What is the Origin of Sex Steroid Sequestration?

This term is central to clinical endocrinology, particularly the study of steroid hormone transport and bioavailability within the circulatory system. 'Sequestration' emphasizes the act of isolating or setting apart the hormone molecules within the circulation, controlling their access to target cells.

What is the Mechanism of Sex Steroid Sequestration?

SHBG, synthesized primarily in the liver, has a high affinity for testosterone and estradiol, forming a large molecular complex with them. When a hormone is bound to SHBG, this complex prevents it from diffusing out of the bloodstream and interacting with intracellular receptors. Therefore, the total concentration of SHBG acts as a physiological buffer, directly regulating the concentration of free, active hormone that can bind to receptors and elicit a biological effect on muscle, bone, and brain tissues.

Sex Steroid Sequestration ∞ Area

Sex Steroid Sequestration

Meaning

Sex Steroid Sequestration is the physiological process where circulating sex hormones, such as testosterone and estrogen, are bound and temporarily inactivated by carrier proteins, predominantly Sex Hormone-Binding Globulin (SHBG). This binding effectively sequesters a large fraction of the hormones, rendering them biologically unavailable to target tissues for receptor interaction. The level of sequestration is a critical determinant of the “free” or bioactive hormone fraction, directly impacting hormonal health and tissue function.