- Pyrogens increase the set-point temperature. Core temperature will be recognized as lower than the new set-point temperature by the anterior hypothalamus. As a result, heat-generating mechanisms (e.g., shivering) will be initiated.
- Pyrogens increase the production of interleukin-1 (IL-1) in granulytic phagocytic cells.
- IL-1 acts on the anterior hypothalamus to increase the production of prostaglandins. Prostaglandins increase set-point temperature, setting in motion the heat-generating mechanism that increase body temperature and produce fever.
- Aspirin reduces fever by inhibiting cyclooxygenase, thereby inhibiting the production of prostaglandins. Therefore, aspirin decreases the set-point temperature. In response, mechanisms that cause heat loss (e.g., sweating, vasodilation) are activated.
- Steroid, like glucocorticoids inhibit the enzyme phospholipase A2; this decreases the release of arachidonic acid and the variety of substances produced from it, such as leukotrienes, prostaglandins, thromboxanes, and prostacyclin. Cortisol owes its fever-reducing action to the hormone's ability to decrease the release of interleukin-1 from granulocytes. However, only in massive doses will the hormone achieve the effects described.
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