Steroid hormones are lipid-soluble signaling molecules derived from cholesterol that regulate gene expression by binding intracellular receptors and traveling through the bloodstream to distant targets. The correct answer is A and C only.

Option Analysis

• A. Steroid hormones bind to specific receptors: True. They diffuse across the cell membrane and bind to specific intracellular (cytoplasmic or nuclear) receptors, forming a hormone-receptor complex.

• B. Steroid hormones bind to DNA to control gene expression: False. The hormone-receptor complex binds to DNA, not the steroid hormone itself; the receptor acts as a transcription factor interacting with hormone response elements on DNA.

• C. Steroid hormones travel to distant tissues through blood: True. Being lipophilic, they circulate bound to carrier proteins in blood (e.g., albumin or sex hormone-binding globulin) to reach distant target cells.

Introduction to Steroid Hormones

Steroid hormones receptors blood transport is key to understanding their endocrine action. Derived from cholesterol, these hormones—like cortisol, estrogen, and testosterone—diffuse through cell membranes due to lipid solubility. They exemplify classic hormone signaling in molecular biology.

Binding to Specific Receptors

Steroid hormones first bind intracellular receptors in the cytoplasm or nucleus. This forms a complex that undergoes conformational change, dissociating heat shock proteins. The activated complex then translocates to the nucleus if needed. This receptor specificity ensures targeted effects.

Gene Expression Mechanism

Unlike peptide hormones, steroid hormones do not directly bind DNA. The receptor-hormone complex binds hormone response elements (HREs) on DNA, modulating transcription. This leads to new protein synthesis, explaining their slow but sustained effects.

Circulation in Blood

Steroid hormones travel to distant tissues through blood, bound to plasma proteins for solubility and protection. Free hormone diffuses into target cells. This allows systemic effects, distinguishing them from local signaling molecules.

Common Exam Insights

In MCQs like “What is true about steroid hormones?”, options test precise mechanisms: A (receptor binding) and C (blood travel) hold, but B misstates direct DNA binding. Useful for NEET, GATE Life Sciences prep.​