Upregulation is a process that makes cells more responsive to stimuli like hormones by increasing the number of receptors on the surface of the cell. It occurs in response to environmental cues that can vary from changes in hormone levels associated with pregnancy to exposure to toxins. The opposite of upregulation is downregulation, where cells become less sensitive to stimuli. These downregulated cells may be said to be “desensitized,” reflecting the fact that more hormones are needed to stimulate the cells.
The body is in a constant state of change and the sensitivity of cells increases and decreases on a regular basis to address environmental factors and regulate physical processes. Upregulation and downregulation keep the cells flexible so they can respond to changing conditions. However, they can also work against the body in some cases, especially when the body is exposed to toxins that it does not recognize.
One example of upregulation can be seen when people exercise more, increasing the sensitivity of cells to insulin. Cells that have become downregulated and are less responsive to insulin can be upregulated through regular exercise to make them more sensitive. This is why exercise is recommended to patients who are developing type two diabetes. In some cases, changing diet and exercise habits can resolve the issue, allowing the patient to make a full recovery. In others, exercising to encourage the cells to upregulate can help the patient control the diabetes.
Pregnant women also undergo upregulation. As pregnancy hormones move through the body, cellular changes occur to prepare for labor and delivery. Cells in the uterus become more sensitive to oxytocin, for example. This increased sensitivity can also happen when people are exposed to certain toxins, or when levels of a hormone are lower than they should be and the body increases the number of receptors for them.
This process reflects one of many tactics the body can use to adapt to changes in its environment. When all of the systems in the body are healthy and working in harmony, upregulation and downregulation can be used to adjust sensitivity to compounds that enter the body or are created by it. In some cases, this creates unintended consequences. For example, patients who use narcotic drugs to manage chronic pain conditions experience downregulation, a decrease in sensitivity caused by the exposure, and as a result, they must increase their dosages in order to have the same effect.