Down regulation is defined as what?

Down regulation is defined as what?

• A. Cell makes fewer hormone receptors, prevents desensitizing
• B. Increased receptor numbers, increases uptake
• C. Receptor blockade
• D. Hormone degradation

Answer: (A)

Down regulation occurs when a cell lowers the number of receptors for a hormone on its surface after sustained, high levels of that hormone. With fewer receptors available, the cell’s responsiveness diminishes, which is desensitization. This mechanism helps prevent overstimulation and keeps signaling balanced. The key idea here is that fewer receptors means reduced sensitivity to the hormone. Increasing receptor numbers would have the opposite effect (upregulation). Blocking the receptor would stop signaling without changing receptor density, and degrading the hormone reduces its amount rather than changing receptor numbers.

Down regulation occurs when a cell lowers the number of receptors for a hormone on its surface after sustained, high levels of that hormone. With fewer receptors available, the cell’s responsiveness diminishes, which is desensitization. This mechanism helps prevent overstimulation and keeps signaling balanced.

The key idea here is that fewer receptors means reduced sensitivity to the hormone. Increasing receptor numbers would have the opposite effect (upregulation). Blocking the receptor would stop signaling without changing receptor density, and degrading the hormone reduces its amount rather than changing receptor numbers.