Up regulation and Down regulation
Upregulation:
- Definition: The process of increasing the number of hormone receptors, making cells more sensitive to hormones.
- Example: Low exposure to glucose (limited intake of sugary foods) allows cells to maintain insulin receptor integrity, enabling them to upregulate receptors when glucose is introduced and respond effectively to insulin.
- Hormonal Example: Elevated estrogen levels can upregulate progesterone levels, resulting in an increase in the number of progesterone receptors on target cells.
Downregulation:
- Definition: The process of decreasing the number of available receptors for a hormone, making cells less sensitive to hormones.
- Example: Prolonged exposure to high levels of insulin leads to receptor degradation, resulting in decreased responsiveness to insulin. This is evident in conditions like insulin resistance associated with type 2 diabetes.
- Hormonal Example: Elevated progesterone levels may downregulate estrogen levels, decreasing the number of estrogen receptors on target cells.
Cell Response to Hormones:
- When cells are exposed to chronically high levels of hormones, such as insulin:
- They may metabolize and degrade hormone receptors to decrease sensitivity.
- Example: Insulin receptor degradation due to high insulin levels.
Insulin and Glucose Uptake:
- If cells take in excessive glucose:
- Glucose can become toxic to cells (due to potential accumulation).
- This can lead to the degradation of insulin receptors, contributing to insulin resistance and elevated blood glucose levels, which is linked to type 2 diabetes.
Estrogen and Progesterone Interaction:
- The interplay of estrogen and progesterone showcases both upregulation and downregulation.
- Elevated estrogen levels lead to upregulation of progesterone receptors, increasing the sensitivity of target cells to progesterone.
- Conversely, elevated progesterone levels can lead to downregulation of estrogen receptors, decreasing sensitivity to estrogen, and thus balancing their effectiveness in the body.