Q.94 As compared lo peplide hormones, steroid hormones take more lime to activate a celluiar response
because

(A) steroid hormones show non-specific binding with diverse sets of receptors.
(B) steroid hormone acts through a receptor which is a transcription factor.
(C) cells that respond to steroid hormones are dormant in nature.
(D) peptide hormones are not transported through plasma while steroid hormones are.

Steroid vs Peptide Hormones: Why Steroids Activate Responses Slower

Steroid hormones trigger slower cellular responses than peptide hormones due to their genomic mechanism involving gene expression. This MCQ highlights key differences in hormone signaling for biology exams.

Correct Answer

(B) steroid hormone acts through a receptor which is a transcription factor.

Steroid hormones, being lipophilic, diffuse across the cell membrane and bind intracellular receptors that function as transcription factors. This hormone-receptor complex translocates to the nucleus, binds hormone response elements, and induces gene transcription and protein synthesis, which takes hours to days for effects to manifest. In contrast, peptide hormones bind cell-surface G-protein coupled receptors, activating rapid second messenger cascades like cAMP or IP3, yielding responses in seconds to minutes.

Option Explanations

(A) Steroid Hormones Show Non-Specific Binding with Diverse Sets of Receptors

Steroid hormones exhibit high specificity for their receptors (e.g., glucocorticoid receptor for cortisol), not non-specific binding. Diverse receptors exist but binding is precise; this doesn’t explain slower action, as receptor affinity relates more to potency than timing.​

(B) Steroid Hormone Acts Through a Receptor Which Is a Transcription Factor (Correct)

The key delay stems from the multi-step genomic pathway: diffusion, receptor binding, nuclear translocation, transcription, mRNA processing, translation, and protein function. Peptide hormones skip this, using pre-existing proteins via phosphorylation, explaining their rapid onset.

(C) Cells That Respond to Steroid Hormones Are Dormant in Nature

Target cells for steroids (e.g., muscle for testosterone) are metabolically active, not dormant. Response speed depends on signaling mechanism, not cell state; dormant cells wouldn’t respond faster to peptides regardless.​

(D) Peptide Hormones Are Not Transported Through Plasma While Steroid Hormones Are

Both types circulate in plasma—peptides freely or loosely bound, steroids tightly bound to carriers like SHBG for solubility. Transport doesn’t dictate activation speed; it’s post-binding intracellular events that differ.​

This comparison underscores genomic vs. non-genomic signaling for exam prep in endocrinology and cell biology.