8.2.3 Role of Oestrogen

• Steps in the mechanism of oestrogen action

  1️⃣ Oestrogen enters the cell via diffusion

  2️⃣ Oestrogen binds to its receptor in the cytoplasm or nucleus

  3️⃣ The oestrogen-receptor complex translocates to the nucleus (if formed in the cytoplasm)

  4️⃣ The complex binds to hormone response elements on DNA

  5️⃣ Transcription of target genes is enhanced
• Match the receptor location with its function:

  Cytoplasm ↔️ Forms hormone-receptor complex; translocates to nucleus

  Nucleus ↔️ Forms hormone-receptor complex; binds to DNA; enhances transcription
• Steps in the mechanism of oestrogen action

  1️⃣ Oestrogen enters the cell via diffusion

  2️⃣ Oestrogen binds to its receptor in the cytoplasm or nucleus

  3️⃣ The oestrogen-receptor complex translocates to the nucleus (if formed in the cytoplasm)

  4️⃣ The complex binds to hormone response elements on DNA

  5️⃣ Transcription of target genes is enhanced
• Match the receptor location with its function:

  Cytoplasm ↔️ Forms hormone-receptor complex; translocates to nucleus

  Nucleus ↔️ Forms hormone-receptor complex; binds to DNA; enhances transcription
• What specific regions on DNA do oestrogen-receptor complexes bind to?

  Hormone response elements
• The binding of the oestrogen-receptor complex to DNA enhances the process of transcription
• Match the hormone with its function in gene expression:

  Oestrogen ↔️ Enhances transcription of target genes involved in female reproductive development and bone density

  Testosterone ↔️ Enhances transcription of genes involved in male reproductive development and muscle mass

  Cortisol ↔️ Influences genes involved in stress response, glucose metabolism, and inflammation
• How does oestrogen enter a target cell?

  Diffusion
• The oestrogen-receptor complex always forms in the cytoplasm before translocating to the nucleus.

  False
• What regions of DNA does the oestrogen-receptor complex bind to in the nucleus?

  Hormone response elements
• The binding of the oestrogen-receptor complex to hormone response elements enhances the transcription
• Match the location of the oestrogen receptor with its function:

  Cytoplasm ↔️ Forms hormone-receptor complex; translocates to nucleus

  Nucleus ↔️ Binds to HREs; enhances transcription
• Excess oestrogen exposure is associated with increased risks of breast cancer and endometrial cancer.

  True
• Match the type of cancer with its association with oestrogen:

  Endometrial cancer ↔️ Prolonged stimulation of uterine lining

  Breast cancer ↔️ Enhanced transcription by ERs
• What is an example of a selective oestrogen receptor modulator (SERM) used in breast cancer treatment?

  Tamoxifen
• Match the treatment type with its description and target cancer:

  SERMs ↔️ Act as agonists or antagonists; target breast cancer

  Aromatase Inhibitors ↔️ Block oestrogen production; target breast cancer

  Oestrogen Antagonists ↔️ Bind to receptors, blocking oestrogen; target breast cancer
• What are the three treatment strategies targeting oestrogen pathways mentioned in the text?

  SERMs, Aromatase Inhibitors, Oestrogen Antagonists
• Selective oestrogen receptor modulators (SERMs) act as agonists or antagonists
• Aromatase inhibitors reduce oestrogen production by blocking the enzyme aromatase.


  True
• Steps in the mechanism of oestrogen action on target cells

  1️⃣ Oestrogen enters the cell by diffusion

  2️⃣ Oestrogen binds to receptors in cytoplasm or nucleus

  3️⃣ Oestrogen-receptor complex translocates to nucleus

  4️⃣ Complex binds to hormone response elements

  5️⃣ Transcription of target genes is enhanced
• What is the role of hormone response elements (HREs) in gene expression?

  Bind oestrogen-receptor complex
• Prolonged exposure to oestrogen can increase the risk of breast and endometrial cancers.


  True
• Match the cancer type with its associated risk:

  Endometrial Cancer ↔️ Prolonged oestrogen stimulation

  Breast Cancer ↔️ Increased oestrogen exposure
• What are two examples of SERMs used in breast cancer treatment?

  Tamoxifen, Raloxifene
• Aromatase inhibitors reduce oestrogen production by blocking the enzyme aromatase
• What type of molecule is oestrogen?

  Steroid hormone
• The structure of oestrogen includes a four-ring backbone with a hydroxyl group at position 3
• Oestrogen receptors are located only in the cytoplasm of target cells.

  False
• How does oestrogen enter a target cell?

  Diffusion
• Oestrogen binds to receptors located in the cytoplasm or the nucleus
• What is the key functional group in oestrogen that distinguishes it from other steroid hormones?

  Hydroxyl group
• Oestrogen receptors are located in the cytoplasm or the nucleus
• Oestrogen enhances the transcription of genes involved in male reproductive development.

  False
• Oestrogen enhances the transcription of target genes involved in bone density.


  True
• Where in the cell are oestrogen receptors located?

  Cytoplasm or nucleus
• What type of hormone is oestrogen?

  Steroid hormone
• Steps in the mechanism of oestrogen action on target cells

  1️⃣ Oestrogen enters the cell by diffusion across the cell membrane.

  2️⃣ It binds to oestrogen receptors in the cytoplasm or nucleus.

  3️⃣ The oestrogen-receptor complex translocates to the nucleus if formed in the cytoplasm.

  4️⃣ In the nucleus, the complex binds to hormone response elements (HREs).

  5️⃣ This binding enhances the transcription of target genes.
• The oestrogen-receptor complex only forms in the cytoplasm.

  False
• Oestrogen regulates gene expression by binding directly to DNA.

  False
• Oestrogen enters the cell by diffusion across the cell membrane