What is the Origin of Steroid Receptor Concentration?

This concept is fundamental to steroid endocrinology, as steroid hormones are lipophilic and typically exert their effects by binding to intracellular receptors. The term emphasizes the quantitative aspect of the target cell's readiness to respond to the hormonal message. It is a critical component of understanding tissue-specific hormonal action.

What is the Mechanism of Steroid Receptor Concentration?

Steroid receptor concentration is primarily regulated at the level of gene expression; the cell can increase or decrease the transcription and translation of the receptor protein. Once synthesized, the receptors reside in the cytoplasm or nucleus, often bound to heat shock proteins, awaiting the hormone. Upon hormone binding, the complex translocates to the nucleus and acts as a transcription factor, directly regulating the expression of target genes, thus initiating the biological effect.

Steroid Receptor Concentration ∞ Area

Steroid Receptor Concentration

Meaning

The total number of intracellular protein receptors available within a target cell to bind and respond to steroid hormones, such as cortisol, testosterone, estrogen, and vitamin D. This concentration is a key determinant of tissue sensitivity; a higher concentration means the cell is more receptive to a given circulating hormone level. This metric is dynamic and can be modulated by disease states, genetic factors, and therapeutic interventions. Clinically, understanding this concentration helps explain why individuals with similar circulating hormone levels can exhibit vastly different biological responses.