What type of secretion do apocrine glands primarily produce?

Apocrine glands primarily produce a secretion that contains lipids and proteins. These glands are primarily found in specific regions of the body, such as the axillae (armpits) and the groin. The secretion from apocrine glands is thicker and can become odorous when it comes into contact with skin bacteria, which is often associated with body odor.

The composition of the secretion—rich in fatty substances and proteins—plays a significant role in signaling and pheromonal communication in certain species. In humans, the secretion is also involved in the function of the skin’s microbiome, contributing to the unique scent of an individual.

The other choices refer to different types of substances not associated with apocrine gland secretions. Water, while present in various secretions, is not the primary endpoint of apocrine gland activity. Similarly, keratin is a protein found in skin, hair, and nails, but it is not secreted by these glands. Vitamin C, although important for skin health, is not produced by apocrine glands. Therefore, lipids and proteins accurately characterize the primary secretion attributed to apocrine glands.