Steroid Hormones: Videos & Practice Problems

Steroid hormones, derived from cholesterol, are classified into five groups: androgens, estrogens, progestins, glucocorticoids, and mineralocorticoids. Androgens, like testosterone, regulate male sexual development, while estrogens, such as estradiol, control female sexual development. Progestins, including progesterone, manage the menstrual cycle and pregnancy. Glucocorticoids, like cortisol, oversee metabolism of carbohydrates, proteins, and lipids, whereas mineralocorticoids, such as aldosterone, regulate kidney excretion of salt and water. Understanding these hormones is crucial for grasping their physiological roles in the body.

Steroid Hormones

In the study of steroid hormones, it is essential to understand that these hormones are derived from cholesterol, which serves as their precursor molecule. Steroid hormones are a type of bio-signaling molecule released by cells or glands, traveling through the body to affect distant cells. They can be classified into five distinct groups based on their physiological responses: androgens, estrogens, progestins, glucocorticoids, and mineralocorticoids.

Androgens, such as testosterone, are primarily responsible for male sexual development and are produced by the gonads, which include the testes. Estrogens, like estradiol, control female sexual development and are also produced by the gonads, specifically the ovaries. Progestins, exemplified by progesterone, play a crucial role in regulating the menstrual cycle and supporting pregnancy in females.

On the other hand, glucocorticoids, such as cortisol, are produced by the adrenal cortex and are involved in the metabolism of carbohydrates, proteins, and lipids, facilitating the breakdown of these macromolecules. Mineralocorticoids, including aldosterone, also produced by the adrenal cortex, are vital for regulating kidney excretion of salt and water, thus influencing fluid balance in the body.

To aid in memorization of these classes, a mnemonic can be utilized: the first letters of "angry elves probably get mad" correspond to androgens, estrogens, progestins, glucocorticoids, and mineralocorticoids, respectively. This playful association can help reinforce the understanding of the steroid hormone classes and their functions.

Overall, this introduction to steroid hormones sets the stage for deeper exploration of their specific functions and roles in the body, which will be covered in subsequent lessons.

Each of the following can be synthesized from cholesterol EXCEPT:

• A. Glucose
• B. Progesterone
• C. Cholic acid
• D. Testosterone
• E. Estradiol

Answer: (A)

Identify the molecule derived from sterols.

• A. Arachidonic acid
• B. Gangliosides
• C. Phosphatidylglycerol
• D. Prostaglandins
• E. Cortisol

Answer: (E)

Which of the following steroid hormones regulates a female's menstrual cycle?

• A. Estrogen
• B. Testosterone
• C. Progesterone
• D. Cortisol

Answer: (C)

Here’s what students ask on this topic:

What are the five classes of steroid hormones and their primary functions?

The five classes of steroid hormones are androgens, estrogens, progestins, glucocorticoids, and mineralocorticoids. Androgens, such as testosterone, regulate male sexual development. Estrogens, like estradiol, control female sexual development. Progestins, including progesterone, manage the menstrual cycle and pregnancy. Glucocorticoids, such as cortisol, oversee the metabolism of carbohydrates, proteins, and lipids. Mineralocorticoids, like aldosterone, regulate kidney excretion of salt and water. Each of these hormones plays a crucial role in maintaining various physiological processes in the body.

How are steroid hormones synthesized from cholesterol?

Steroid hormones are synthesized from cholesterol through a series of enzymatic reactions. Cholesterol serves as the precursor molecule. The process begins with the conversion of cholesterol to pregnenolone, which then undergoes further enzymatic modifications to form different steroid hormones. These modifications include hydroxylation, dehydrogenation, and isomerization reactions, which are catalyzed by specific enzymes located in the mitochondria and endoplasmic reticulum of steroidogenic cells. The final products are the five classes of steroid hormones: androgens, estrogens, progestins, glucocorticoids, and mineralocorticoids.

What is the role of glucocorticoids in metabolism?

Glucocorticoids, such as cortisol, play a crucial role in the metabolism of carbohydrates, proteins, and lipids. They help regulate blood glucose levels by promoting gluconeogenesis in the liver, which is the synthesis of glucose from non-carbohydrate sources. Glucocorticoids also facilitate the breakdown of proteins into amino acids and lipids into fatty acids, which can be used as energy sources. Additionally, they have anti-inflammatory and immunosuppressive effects, making them important in stress responses and in the treatment of inflammatory and autoimmune conditions.

How do mineralocorticoids regulate kidney function?

Mineralocorticoids, such as aldosterone, regulate kidney function by controlling the excretion of salt and water. Aldosterone acts on the distal tubules and collecting ducts of the nephron in the kidneys, promoting the reabsorption of sodium ions (Na⁺) and the excretion of potassium ions (K⁺). This sodium reabsorption leads to water retention, which helps maintain blood volume and blood pressure. By regulating the balance of electrolytes and water, mineralocorticoids play a vital role in maintaining homeostasis in the body.

What are the differences between androgens and estrogens?

Androgens and estrogens are both classes of steroid hormones, but they have different roles and are produced in different quantities in males and females. Androgens, such as testosterone, are primarily involved in the development and maintenance of male characteristics, including muscle mass, deep voice, and facial hair. They are produced mainly by the testes in males. Estrogens, like estradiol, are primarily involved in the development and maintenance of female characteristics, such as breast development and regulation of the menstrual cycle. They are produced mainly by the ovaries in females. Both hormones are present in both sexes but in different proportions.