Steroid hormones

Definition

Steroid hormones are a class of hormones derived from cholesterol that play critical roles in regulating various physiological processes in the body. These hormones are lipophilic, meaning they can easily pass through cell membranes to bind with specific receptors inside target cells, leading to changes in gene expression and cellular function. Common steroid hormones include cortisol, testosterone, and estrogen, which influence metabolism, immune response, and reproductive functions.

5 Must Know Facts For Your Next Test

1. Steroid hormones are classified into two categories: corticosteroids (like cortisol) which are involved in stress response, and sex steroids (like testosterone and estrogen) which regulate reproductive functions.
2. Unlike peptide hormones that act through cell surface receptors, steroid hormones enter target cells and bind to intracellular receptors, influencing gene expression directly.
3. Steroid hormones can have long-lasting effects on the body due to their ability to alter gene transcription and protein synthesis.
4. The synthesis of steroid hormones primarily occurs in the adrenal glands and gonads (ovaries and testes).
5. Dysregulation of steroid hormone levels can lead to various disorders, such as adrenal insufficiency or hormonal imbalances affecting reproductive health.

Review Questions

• How do steroid hormones differ from peptide hormones in terms of their mechanism of action within target cells?
  • Steroid hormones differ from peptide hormones primarily in their mechanism of action. While peptide hormones bind to receptors on the cell surface and activate signaling pathways, steroid hormones are lipophilic and can easily diffuse through cell membranes. Once inside the target cell, they bind to specific intracellular receptors, forming a hormone-receptor complex that directly influences gene expression by acting on DNA in the nucleus. This leads to changes in protein synthesis and cellular function over a longer time frame compared to peptide hormones.
• Discuss the roles of corticosteroids and sex steroids in maintaining homeostasis within the body.
  • Corticosteroids and sex steroids play vital roles in maintaining homeostasis by regulating different physiological processes. Corticosteroids, like cortisol, are crucial for managing stress responses, influencing metabolism, and modulating immune functions. They help the body respond effectively to stressors by increasing glucose availability and suppressing inflammation. On the other hand, sex steroids such as testosterone and estrogen regulate reproductive functions, influence secondary sexual characteristics, and affect bone density and muscle mass. Together, these steroid hormones contribute to a balanced internal environment essential for overall health.
• Evaluate how abnormalities in steroid hormone levels can impact health and what conditions might arise from such imbalances.
  • Abnormalities in steroid hormone levels can significantly impact health and lead to various conditions. For instance, excessive production of cortisol can result in Cushing's syndrome, characterized by obesity, high blood pressure, and skin changes. Conversely, insufficient cortisol production may lead to Addison's disease, causing fatigue, weight loss, and low blood pressure. In terms of sex steroids, low testosterone levels in males can result in decreased libido, fatigue, and muscle loss. Additionally, imbalances in estrogen levels can affect menstrual cycles in females and contribute to osteoporosis. Therefore, maintaining balanced steroid hormone levels is crucial for preventing these health issues.

Related terms

cholesterol: A type of lipid that serves as a fundamental building block for the synthesis of steroid hormones.

hormone receptor: A protein molecule that specifically binds to a hormone, triggering a cellular response.

endocrine system: The network of glands that produce and secrete hormones, including steroid hormones, into the bloodstream to regulate various bodily functions.