Which human hormone is the basis for steroids? Select one: A. adrenalin. B. norepinephrine. C. human growth hormone. D. testosterone.
The correct answer and explanation is:
The correct answer is: D. testosterone
Explanation:
Steroids are a large class of organic compounds characterized by a specific molecular structure of four fused rings. In the human body, steroid hormones are synthesized from cholesterol and include important hormones like testosterone, estrogen, cortisol, and aldosterone.
Testosterone is a key steroid hormone, primarily classified as an androgen. It serves as the basis for many steroid hormones because it is one of the principal sex hormones that controls the development of male characteristics, but it also acts as a precursor for other steroid hormones.
Here’s why testosterone is the basis for steroids:
- Steroid Hormone Structure: Steroid hormones share a common structural backbone derived from cholesterol. Testosterone itself is a steroid hormone synthesized from cholesterol through a series of enzymatic steps.
- Precursor Role: Testosterone can be converted into other steroid hormones. For example:
- It can be aromatized into estradiol, an important estrogen hormone.
- It shares pathways with other steroids like dihydrotestosterone (DHT), which is a more potent androgen.
- It is involved in the biosynthesis of other adrenal steroids.
- Function: Testosterone regulates various physiological processes such as muscle mass, bone density, libido, and secondary sexual characteristics in males. Due to its steroidal nature, testosterone influences gene expression by binding to androgen receptors inside cells.
Why not the others?
- A. Adrenaline (epinephrine) and B. Norepinephrine are catecholamine hormones, derived from the amino acid tyrosine, not steroids. They are involved in the fight-or-flight response, affecting heart rate and blood pressure, but they are structurally different from steroid hormones.
- C. Human Growth Hormone (HGH) is a peptide hormone secreted by the pituitary gland. It is a protein-based hormone that stimulates growth and cell reproduction, but it is not a steroid.
Summary:
Steroid hormones are cholesterol-derived molecules, and testosterone is a primary steroid hormone serving as a foundation for many other steroids in the body. Unlike adrenaline, norepinephrine, or growth hormone, testosterone belongs to the steroid family and thus is the correct answer.