pyrogeni

Pyrogeni refers to substances that cause fever. These can be endogenous, meaning they are produced within the body, or exogenous, meaning they originate from outside the body. Endogenous pyrogens, such as cytokines like interleukin-1, tumor necrosis factor alpha, and interleukin-6, are released by immune cells in response to infection or inflammation. Exogenous pyrogens are typically components of microorganisms, such as lipopolysaccharides from gram-negative bacteria or peptidoglycans from gram-positive bacteria, or even certain medications or foreign materials.

When pyrogens enter the bloodstream, they travel to the hypothalamus in the brain, which acts as the body's thermostat. Here, they stimulate the production of prostaglandins, which then reset the hypothalamic set-point to a higher temperature. This elevation in body temperature, known as fever, is a common physiological response to infection and inflammation. While fever can be uncomfortable, it is generally considered a beneficial defense mechanism. It can inhibit the growth of some pathogens, enhance the activity of immune cells, and speed up metabolic processes that aid in recovery. However, excessively high fevers can be dangerous and require medical attention.