What is the Origin of Nuclear Progesterone Receptors?

The term is derived from the cell's structural components, where 'Nuclear' specifies the location of the receptor, and 'Progesterone Receptors' identifies the hormone ligand. The discovery of these intracellular receptors was a major advancement in endocrinology. This finding explained how lipophilic steroid hormones regulate cell function by directly influencing the genome and transcriptional machinery.

What is the Mechanism of Nuclear Progesterone Receptors?

Progesterone binds to the nuclear PR, inducing a conformational change that promotes receptor dimerization and subsequent binding to specific Progesterone Response Elements (PREs) in the DNA promoter regions of target genes. This binding event recruits co-regulator proteins, leading to the initiation or repression of transcription. The differential expression and activation of the PR-A and PR-B isoforms allow for a complex, tissue-specific modulation of cellular growth, differentiation, and secretory functions, particularly in the endometrium.

Nuclear Progesterone Receptors ∞ Area

Nuclear Progesterone Receptors

Meaning

Nuclear Progesterone Receptors (PRs) are ligand-activated transcription factors located within the cell nucleus that mediate the genomic actions of the steroid hormone progesterone. These receptors, existing as two main isoforms, PR-A and PR-B, are critical components of the female reproductive tract, breast, and central nervous system, regulating gene expression to control diverse physiological processes. Their presence is a key diagnostic and prognostic marker in hormone-sensitive cancers.