Which of the following belongs to steroidal receptor superfamily?
**Question:** Which of the following belongs to steroidal receptor superfamily?
A. Glucocorticoid receptor
B. Androgen receptor
C. Estrogen receptor
D. Progesterone receptor
**Core Concept:** Steroidal receptors are a group of ligand-activated transcription factors that mediate the effects of steroid hormones on target cells. Steroids are a diverse class of lipophilic compounds that include hormones, neurosteroids, and eicosanoids. Steroid hormones are synthesized in the adrenal glands, gonads, and brain and act as signaling molecules to regulate various physiological processes, including growth, differentiation, and gene expression. Steroidal receptors belong to the nuclear receptor superfamily, which includes transcription factors that regulate gene expression in response to steroid hormones and other ligands.
**Why the Correct Answer is Right:** The steroidal receptors belong to the nuclear receptor superfamily because they are activated by steroid hormones, which are lipophilic molecules that can penetrate the lipid bilayer of cell membranes and bind to intracellular receptors. These receptors, including the glucocorticoid receptor, androgen receptor, estrogen receptor, and progesterone receptor, translocate to the nucleus upon ligand binding and regulate gene expression, thereby mediating the biological effects of steroid hormones.
**Why Each Wrong Option is Incorrect:**
A. Glucocorticoid receptor: Correct
B. Androgen receptor: Correct
C. Estrogen receptor: Correct
D. Progesterone receptor: Correct
**Why Option A is Incorrect:** Glucocorticoid receptors are a subclass of nuclear receptors activated by glucocorticoids, which are synthesized in the adrenal glands and regulate immune response, inflammation, and energy homeostasis. They are involved in the pathogenesis of various diseases, including sepsis, rheumatoid arthritis, and asthma.
**Why Option B is Incorrect:** Androgen receptors are activated by androgens, which are synthesized in the testes and adrenals and regulate male sexual development, spermatogenesis, and male secondary sexual characteristics. They are involved in the pathogenesis of diseases such as prostate cancer and androgenetic alopecia.
**Why Option C is Incorrect:** Estrogen receptors are activated by estrogens, which are synthesized in the ovaries and hypothalamus and regulate female reproductive function, bone mineral density, and cardiovascular health. They are involved in the pathogenesis of diseases such as breast cancer and osteoporosis.
**Why Option D is Incorrect:** Progesterone receptors are activated by progesterone, which is synthesized in the ovaries and placenta and regulates female reproductive function, pregnancy, and immune response. They are involved in the pathogenesis of diseases such as endometriosis and preeclampsia.
**Core Concept:** Steroidal receptors are essential components of the steroid hormone signaling pathway, which is crucial for maintaining homeostasis in the human body. They are involved in the regulation of diverse physiological processes, including reproduction, immune response, and tissue remodeling.
**Why Option A is Correct:** Glucocorticoid receptors are activated by glucocorticoids, which regulate immune response, inflammation, and energy homeostasis. Gl