What is the Origin of Endocrine Feedback Override?

This phrase combines "endocrine," relating to secreted internal messengers, with "feedback," the regulatory loop concept, and "override," meaning to supersede or bypass established control. The concept is central to understanding pharmacodynamics when administering exogenous hormones or potent signaling molecules. It describes a departure from physiological equilibrium enforced by external input.

What is the Mechanism of Endocrine Feedback Override?

An override typically occurs when high concentrations of an exogenous hormone or analogue saturate target receptors, signaling the hypothalamus or pituitary to cease releasing tropic hormones like LH, FSH, or ACTH. This suppression halts the downstream production of native hormones, such as testosterone or cortisol, by the primary glands. The mechanism necessitates specific antagonist or agonist activity that effectively "shuts down" the upstream signaling required for homeostasis maintenance.

Endocrine Feedback Override ∞ Area

Endocrine Feedback Override

Meaning

The deliberate interruption or circumvention of the normal negative or positive feedback mechanisms governing the hypothalamic-pituitary-gonadal (HPG) or hypothalamic-pituitary-adrenal (HPA) axes by external agents or intense stimuli. Clinically, this is observed when exogenous substances suppress endogenous hormone production, leading to a state where the body’s intrinsic regulatory capacity is temporarily disabled. Recognizing an override is critical for accurate diagnostic interpretation.