Dexamethasone is a synthetic steroid drug that mimics natural glucocorticoid hormones and is widely used to treat severe inflammatory conditions.
Like natural glucocorticoids, dexamethasone is hydrophobic.
Explain why dexamethasone can rapidly enter a cell by passing through its cell-surface membrane.
In the cytoplasm, dexamethasone binds to a specific glucocorticoid receptor (GR). GR is a protein.
Suggest and explain why dexamethasone binds to a specific GR.
The binding of dexamethasone to a GR changes the shape of the receptor. This activated GR molecule then enters the nucleus and stimulates the transcription of specific anti-inflammatory genes.
Suggest how the activated GR stimulates gene transcription.
The gene that codes for GR has a variable number of CAG triplet repeats. Researchers investigated whether the number of CAG repeats was associated with high clinical sensitivity to dexamethasone.
Table 1 shows the statistical results from this investigation.
Table 1
| Number of CAG repeats in the GR gene | Probability (PPP) value |
|---|---|
| ≤12\le 12≤12 | 0.02 |
| ≤14\le 14≤14 | 0.18 |
| ≥22\ge 22≥22 | 0.04 |
| ≥24\ge 24≥24 | 0.07 |
| ≥26\ge 26≥26 | 0.21 |
What can you conclude from the data in Table 1?
