How do estrogen and testosterone alter cell function? Khan Academy provides a comprehensive explanation of these hormones’ roles in the body. Both estrogen and testosterone are sex hormones that play crucial roles in the development and maintenance of sexual characteristics in humans. They also influence various cellular processes, affecting the function of cells in different ways.

Estrogen, primarily produced in the ovaries in females and the adrenal glands in both sexes, is responsible for the development of female reproductive organs and secondary sexual characteristics such as breast growth and the distribution of body fat. In males, estrogen levels are lower but still present. Estrogen can alter cell function through several mechanisms:

1. Receptor Activation: Estrogen binds to estrogen receptors (ERs) in the cell nucleus, leading to the activation of gene expression. This can result in the growth and differentiation of cells, as well as the regulation of various cellular processes.

2. Influence on Gene Expression: Estrogen can modulate the expression of genes involved in cell growth, differentiation, and apoptosis (cell death). This hormone can either promote or inhibit these processes, depending on the context.

3. Stimulation of Cell Proliferation: Estrogen can stimulate the proliferation of certain cell types, such as breast and endometrial cells. This is crucial for the development of female reproductive organs and the menstrual cycle.

4. Influence on Bone Health: Estrogen plays a vital role in maintaining bone density. It can enhance the activity of osteoblasts (bone-forming cells) and inhibit the activity of osteoclasts (bone-resorbing cells), thereby promoting bone health.

Testosterone, predominantly produced in the testes in males and the ovaries in females, is responsible for the development of male reproductive organs and secondary sexual characteristics such as muscle mass, facial hair, and deep voice. Testosterone can alter cell function through the following mechanisms:

1. Androgen Receptor Activation: Testosterone binds to androgen receptors (ARs) in the cell nucleus, leading to the activation of gene expression. This can result in the growth and differentiation of cells, as well as the regulation of various cellular processes.

2. Stimulation of Protein Synthesis: Testosterone can stimulate the synthesis of proteins, which is crucial for muscle growth and development.

3. Influence on Gene Expression: Testosterone can modulate the expression of genes involved in cell growth, differentiation, and apoptosis. This hormone can either promote or inhibit these processes, depending on the context.

4. Promotion of Sperm Development: In males, testosterone is essential for the development and maturation of sperm cells.

Both estrogen and testosterone play critical roles in the regulation of cellular function. Their interactions with specific receptors and influence on gene expression can lead to a wide range of effects on cell growth, differentiation, and survival. Khan Academy’s explanation of these mechanisms provides a solid foundation for understanding the complex interplay between hormones and cell function.