Answer:
Exogenous pyrogen:
Exogenous pyrogen may be defined as a substance that produce fever from the outside environment. The exogenous pyrogen are heavier in weight than endogenous pyrogen. Generally, lipopolysaccharide, bacterial toxins and virus acts as exogenous pyrogen.
Endogenous pyrogen:
Endogenous pyrogen may be defined as the substance that produce fever from the inside environment. The exogenous pyrogen are lighter in weight than exogenous pyrogen. Generally, interleukin and tumor necrosis factors acts as endogenous pyrogen.