What is the Origin of Steady-State System?

A concept borrowed from chemistry and pharmacokinetics, where "steady-state" denotes a dynamic equilibrium within an open system. In endocrinology, the term is applied to therapeutic dosing regimens, distinguishing the constant concentration achieved after multiple doses from the fluctuating levels seen after a single dose.

What is the Mechanism of Steady-State System?

In hormone replacement therapy, the mechanism to achieve steady-state involves administering a hormone at regular intervals that match its elimination half-life. For example, a testosterone dose is given frequently enough to ensure that the amount cleared since the last dose is replaced by the new dose. This balanced input and output prevents peaks and troughs in the circulating concentration, thereby maintaining continuous and optimal receptor saturation and minimizing adverse effects.

Steady-State System ∞ Area

Steady-State System

Meaning

A physiological state where the concentration of a substance, such as a hormone or drug, remains relatively constant over time because the rate of its input or production precisely equals the rate of its output or clearance. In hormonal health, achieving a steady-state concentration of an administered hormone is the primary goal of hormone replacement therapy. This equilibrium is crucial for ensuring stable tissue exposure and consistent biological effect.