What is the Origin of Bio-Active Hormones?

The term combines Bio-, from the Greek bios (life), signifying a biological effect, and Active, denoting functional capacity. This concept originated from the understanding of plasma protein binding, particularly the role of Sex Hormone-Binding Globulin (SHBG) and albumin, in regulating hormone availability. It shifts the focus from simple quantity to functional efficacy within the endocrine system.

What is the Mechanism of Bio-Active Hormones?

The mechanism centers on the principle of mass action and receptor availability. Only the unbound hormone molecule can diffuse across cell membranes or access membrane-bound receptors to initiate intracellular cascades. Carrier proteins, like SHBG, act as a circulating reservoir, releasing hormones only when the free concentration drops, thereby stabilizing the endocrine signal and preventing rapid clearance.

Bio-Active Hormones ∞ Area

Bio-Active Hormones

Meaning

Hormones that are unbound to carrier proteins and are thus readily available to interact with target cell receptors to elicit a biological response. In clinical endocrinology, this fraction, often referred to as “free hormone,” represents the physiologically relevant portion driving cellular signaling. Assessing the bio-active fraction provides a more accurate picture of tissue-level hormonal status than total hormone measurements.