Axillary glands

Achsel-. shoulder, axillary, -driise,/. (Physiol.) axillary gland, -grube, -hdhle, /. armpit, axilla. 

Can hnmans reliably identify gender and individnals by body odors The answer to this qnestion matters very mnch in a nnmber of contexts of social and sexnal behavior snch as parent-offspring bonding, mate choice, or nepotism. A classical experiment has examined the role of the axillary odor, the most powerfnl hnman scent. This odor is the resnlt of bacterial action on the secretion of the axillary glands. These skin glands are of the apocrine type which is a modified sweat gland that prodnces an aqneons secretion. 

Solomon, S. E., 1984, The characterisation and distribution of cells lining the axillary gland of the adult green turtle (Chelonia mydas L.),... 

Evidence has been accumulating that extracellular metabolic activity of microorganisms, mainly bacteria, occurs within skin glands and on the skin surface (Albone, 1997). Sterile human apocrine secretions do not develop the characteristic axillary odour (Shelley et al., 1953). In the salivary secretions of the boar, transformations of the pheromonal 16-androstene steroids 2. were attributed to the microbial flora (Booth, 1987). 

Spielman A., Sunavala G., Harmony J., Stuart W., et al. (1998). Identification and immunohistochemjcal localization of protein precursors to human axillary odors in apocrine glands and secretions. Arch Dermatol 134, 813-818. 

Apocrine glands produce a viscous secretion that contains compounds related to communication between individuals of a species, by acting as a sex attractant or as territorial marker. In humans, these glands are located only in the axillary, pubic, and perianal region. 

FIGURE 3.6 Rathke s glands in turtles and tortoises. Axillary (a) and inguinal (i) pores (gland openings) are shown in Chelonia mydas. (From Ehrenfeld and Ehrenfeld, 1973.)... 

Zeng, X.-N., Leyden, J. J., Brand, J. G., etal. (1992). An investigation of human apocrine gland secretion for axillary odor precursors. JournalofChemicalEcology 18,1039-1055. 

The androgens stimulate the development of the male secondary structures, such as the penis, scrotum, seminal vesicles, prostate gland, vas deferens and epididymis. The deepening of the voice, the growth of pubic, axillary, body, and facial hair, as well as the development of the characteristic musculature of the human male, are also under the influence of testosterone. If the testes fail to develop or are removed prior to puberty, these changes do not occur. Thus, testosterone is essential for reproductive function of the male. 

The adrenal glands play an important role in pubertal development. Termed adrenarche, the maturation of a prominent zona reticularis, the innermost layer of the cortex, begins around age six to eight in girls, resulting in increased secretion of the adrenal androgens, dehydroepiandrosterone (DHEA) and DHEA sulfate (Beckman Feuston, 2003). The rise in these hormones leads to the development of pubic and axillary hair. Recent evidence suggests... 

Axillary and pubic hairs are quite similar in terms of growth rate (approximately 0.3 mm/d) and growth/rest cycle durations (11-18 months/12-17 months). They are both exposed to sweat and sebum secretions in addition to the secretions of the apocrine glands which are present only in the axilla and pubic area and discharge directly into the hair follicle rather than onto the surface of the surrounding skin. Axillary hair is less exposed to environmental contamination, but may be subjected to cosmetic treatments. Pubic hair may be contaminated by urine. Both types of hair are composed of ambosexual follicles. 

Exocrine glands there is increased secretion most noticeably of the salivary, lachrymal, bronchial and sweat glands. The last are cholinergic, although anatomically part of the sympathetic system some sweat glands, e.g. axillary, may be adrenergic. 

Thus, Amoore suggests that, if we have a specific olfactory receptor for a given odorant then that odorant might be naturally given off by the body. The sweaty odor of isovaleric acid is probably part of the foot odor and is produced by the action of skin bacteria on apocrine secretion (see below). Pyrolline, the spermous odor, has been shown to be produced by enzymatic breakdown of the polyamines in semen (40). Androst-16-en-3-one, the urinous primary odor, has axillary-like odor the related androstenol, which is found in urine, is perceived as a musky odor to some individuals (41). Both steroids are found in axillary sweat and may be formed as metabolites of apocrine secretion. Chemicals which fit the malty anosmia have not as yet been reported from human odor sources. The natural musks, such as cycloheptadecenone (civet), were first obtained from animal scent glands. 

Spielman, A.I., Harmony, J.A.K., Stuart, W.D., Leyden, J.J., Sunavala, G., Turner, G., Vowels, B.R., Lam, W.C., Yang, S. Preti, G. 1998. Identification and immunohistochemical localization of protein precursors to human axillary odor in apocrine glands and secretions. Arch. Dermatol., 134, in press. 

---