Which hormone is characterized by its lipid-solubility and ability to act as a transcription factor?

Which hormone is characterized by its lipid-solubility and ability to act as a transcription factor?

• A. Insulin
• B. Epinephrine
• C. Testosterone
• D. Cortisol

Answer: (C)

Testosterone is characterized by its lipid solubility and its ability to function as a transcription factor. This steroid hormone is derived from cholesterol, which allows it to easily cross cell membranes and enter target cells. Once inside, testosterone binds to androgen receptors in the cytoplasm or nucleus, forming a hormone-receptor complex that translocates to the nucleus. There, this complex interacts with specific DNA sequences, promoting or inhibiting the transcription of target genes involved in various physiological processes, including muscle growth, development of male reproductive tissues, and regulation of other important metabolic functions. In contrast, insulin and epinephrine are peptide and amine hormones, respectively, which are not lipid-soluble and primarily act through cell surface receptors and second messenger systems, leading to rapid cellular responses rather than direct modulation of gene expression. Cortisol, while also a steroid hormone that can act as a transcription factor, is typically less emphasized in this context when focusing solely on the primary hormone associated with those characteristics, making testosterone the more definitive answer in this instance.

Testosterone is characterized by its lipid solubility and its ability to function as a transcription factor. This steroid hormone is derived from cholesterol, which allows it to easily cross cell membranes and enter target cells. Once inside, testosterone binds to androgen receptors in the cytoplasm or nucleus, forming a hormone-receptor complex that translocates to the nucleus. There, this complex interacts with specific DNA sequences, promoting or inhibiting the transcription of target genes involved in various physiological processes, including muscle growth, development of male reproductive tissues, and regulation of other important metabolic functions.

In contrast, insulin and epinephrine are peptide and amine hormones, respectively, which are not lipid-soluble and primarily act through cell surface receptors and second messenger systems, leading to rapid cellular responses rather than direct modulation of gene expression. Cortisol, while also a steroid hormone that can act as a transcription factor, is typically less emphasized in this context when focusing solely on the primary hormone associated with those characteristics, making testosterone the more definitive answer in this instance.