What Are Apocrine Glands?
Apocrine glands are specialized sweat glands located exclusively in the axillary (armpit) and pubic regions that produce sweat through a unique secretory mechanism involving the release of part of the cell cytoplasm. 1
Anatomical Location and Distribution
- Apocrine glands are found only in specific body regions: the armpits and pubic area. 1
- These glands are always connected to hair follicles, unlike eccrine sweat glands which are distributed throughout the body. 2
- The apocrine gland-containing skin does not always correspond exactly to the hair-bearing area in these regions. 3
Unique Secretory Mechanism
- Apocrine glands are characterized by "decapitation secretion," where the apical part of the cell cytoplasm is pinched off and released into the gland lumen, forming structures called "aposomes." 4, 5
- This secretory process involves the loss of cellular fragments, entire organelles (including mitochondria, Golgi apparatus, and portions of endoplasmic reticulum), and hundreds to thousands of proteins. 6
- The mechanism shares similarities with cytokinesis and involves proteins such as actin, myosin II, tubulin, anillin, and cofilin in the formation and release of apical protrusions. 5
Function and Clinical Significance
- The exact physiological role of apocrine glands in humans remains unknown. 2
- Apocrine glands produce sweat, though their primary function differs from eccrine glands, which regulate body temperature through hypotonic fluid secretion. 1
- These glands can be involved in pathological conditions, particularly hidradenitis suppurativa, which represents recurrent infection of apocrine glands causing larger, tender, draining lesions. 1
Distinguishing Features from Eccrine Glands
- Unlike eccrine glands that show no cytological changes during secretion and are present throughout the body for thermoregulation, apocrine glands demonstrate characteristic cellular changes and limited anatomical distribution. 2
- Eccrine glands deliver hypotonic solution to the skin surface for temperature regulation while preserving sodium, whereas apocrine secretion involves complex proteinaceous mixtures. 1, 6
Clinical Pitfalls
- Folliculitis in the pubic region can be confused with apocrine gland pathology but represents infection of hair follicles rather than apocrine glands, presenting as smaller papules and pustules. 1
- Folliculitis is particularly common with pubic hair shaving and requires counseling on proper shaving technique with adequate lubrication. 1