What is the Origin of Hormonal Bioavailability Assessment?

The term is rooted in pharmacokinetics and endocrinology, where bioavailability is a measure of the extent to which a substance is absorbed and becomes available at the site of physiological activity. In endocrinology, this concept applies specifically to the dynamic equilibrium between protein-bound and free hormone fractions in the plasma. It represents a sophisticated, functional view of endocrine status.

What is the Mechanism of Hormonal Bioavailability Assessment?

Hormones circulate bound to plasma proteins, primarily albumin and globulins, which act as reservoirs and carriers. Only the free, unbound hormone is capable of diffusing across cell membranes to interact with intracellular receptors and elicit a biological response. The assessment mechanism involves either direct measurement of the free fraction or calculation via indices that account for the concentration of binding proteins, such as SHBG.

Hormonal Bioavailability Assessment ∞ Area

Hormonal Bioavailability Assessment

Meaning

Hormonal Bioavailability Assessment is the clinical process of determining the fraction of a total circulating hormone that is free, unbound, and therefore biologically active and available to target tissues. This assessment is critical because total hormone levels often include a large, inactive portion bound to transport proteins, which can be misleading regarding the true physiological effect. Accurate bioavailability measurement is essential for precise diagnosis of deficiency or excess and for optimizing hormone replacement therapy.