Steroid hormones

Options

A. have only cell surface receptors
B. are lipophobic
C. act through altering the activity of proteins in the target cell
D. are produced by only adrenal cortex

Answer

### Step-by-Step Solution:

1. **Understanding Steroid Hormones**:
- Steroid hormones are a class of hormones that are derived from cholesterol. They include hormones such as estrogen, testosterone, and cortisol.

2. **Analyzing the Options**:
- **Option A**: "Have only cell surface receptors"
- This statement is incorrect. Steroid hormones can penetrate the cell membrane and have receptors both on the cell surface and inside the cell.

- **Option B**: "Are lipophobic"
- This statement is also incorrect. Steroid hormones are lipophilic, meaning they can dissolve in lipids and easily pass through the lipid bilayer of cell membranes.

- **Option C**: "Act through altering the activity of proteins in the target cell"
- This statement is correct. Steroid hormones enter the cell, bind to specific intracellular receptors, and then influence gene expression and protein synthesis, thereby altering the activity of proteins in the target cell.

- **Option D**: "Are produced by only adrenal cortex"
- This statement is misleading. While the adrenal cortex produces steroid hormones (like cortisol and aldosterone), other steroid hormones such as estrogen and testosterone are produced by the gonads (ovaries and testes).

3. **Conclusion**:
- After evaluating all the options, the correct answer is **Option C**: "Act through altering the activity of proteins in the target cell."