Fever, and temperature regulation at large, are controlled by intricate processes of the human brain. The brain, or more specifically, the region of the brain known as the hypothalamus, plays a central role in the cause and resolution of fevers.
What are the components involved?
Before we get into the nitty gritty of how fevers are caused and how they are subsequently normalised, let’s find out more about the key players involved in this response.
1. The Hypothalamus
The hypothalamus is a tiny, almond-shaped structure located at the base of the brain. The hypothalamus is instrumental in regulating many vital processes that govern our life, such as hunger, sleep, thirst, circadian rhythms and relevantly to us, body temperature. The hypothalamus is also crucial as a bridge between the nervous and endocrine systems, playing a key role in the activation of several “master” hormones of the pituitary gland.
2. Pyrogens
The term “pyrogen” (Greek, meaning “fever producer”) refers to a class of cellular messenger proteins which play a key role in the signalling response associated with fever.
Pyrogens can be exogenous or endogenous. Exogenous pyrogens (eg. Lipopolysaccharide) are substances produced by infectious agents like bacteria, which our bodies have evolved to respond to with a temperature increase. Usually, they work indirectly by stimulating the production of endogenous pyrogens (eg. Interleukin-1, Interleukin-2, TNF-alpha), which are “cytokines” which form a part of the body’s immune system. They play the role of alerting the hypothalamus to signs of infection, which prompts an increase in the “set-point” of the hypothalamus.