They degranulate late following cell activation, and degranulation occurs at acid pH's. The granule content includes myeloperoxidase, lysozyme, acid hydrolases, elastase, and cathepsins. These are most prominent in more mature cells. They degranulate early following cell activation. Degranulation occurs at basic pH's.
Granule content includes lysozyme, collagenase, and lactoferrin.
Neutrophils of several species have more distinct, eosinophilic granules and are called heterophils. Rabbits, guinea pigs, rats, reptiles, fish and birds have heterophils. Neutrophils are highly-differentiated cells which cannot divide. They have abundant cytoplasmic glycogen stores and cellular respiration is primarily by anaerobic glycolysis. This form of respiration allows the neutrophil to maintain effective function in hypoxic necrotic tissue and exudates.