Axilla, human

Leyden J., McGinley K., Hoelzle K., Labows J., et al. (1981). The microbiology of the human axillae in relation to axillary odors. J Invest Dermatol 77, 413-416. 

It is important to identify and measure the concentrations of a number of compounds in a mixture simultaneously for several reasons. First, among related compounds there may exist precursors of active ones, and pathways of pheromone synthesis may be elucidated. This is true for steroids in the human axilla. Nixon etal. (1988) determined the concentration of five steroids extracted from axillary hair of adult men aged 18 to 40 years. The relationships in concentrations between the two ketones 5Q -androst-16-en-3-one and 4,16-androstadien-3-one suggest that axillary bacteria reduce the former to the latter with the aid of the enzyme 4-ene-5a-reductase. Humans have a low olfactory threshold for several 16-androstenes, and the fact that some men have large quantities of 16-androstenes (Nixon etal., 1988) is biologically suggestive. 

Humans Homo sapiens (E)-3-Methyl-2-hexenoic acid Axilla Zeng etal., 1991... 

The apocrine glands in the axilla can secrete enormous amounts of steroids such as dihydrotestosterone and pregnenolone (Brooksbank, 1970). Three single steroid compounds have also been tested on T-shirts. Surprisingly, both sexes attributed androstenol to females. Two other synthetic compounds were attributed to one or the other sex, depending on concentration, and one was perceived as very negative. Androstenol and the two synthetic compounds have very low olfactory thresholds for humans. 

FIGURE 18.10 Increased synthesis of profilaggrin/filaggrin in human axilla skin detected by immunohisto-chemistry following a 3 week application of a 1 % petroselinic acid formulation. 

Human Toxicity Zirconium and its salts generally have low systemic toxicity. A granulomatous disease of the skin, particularly in the axilla, has been reported in users of a deodorant contg sodium zirconium lactate see E. Browning, Toxicity of Industrial Metals (Appleton-Century-Crofts, New York, 2nd ed., 1969) pp 356-360, Consult latest Government regulations on use in aerosol antiperspirants. 

Zeng X., Leyden L., Lawley H., Sawano K., Nohara I., and Preti G., Analysis of characteristic odors from human male axillae, J. Chem. EcoL, 17, 1469-1492, 1991. 

These compounds would also be irritating to human skin. In contrast, dermal exposure to zinc oxide did not usually cause skin irritation to humans and animals. However, a few workers who routinely became covered with zinc oxide dust have had pustules on the axilla and inner thighs possibly formed in response to plugging of glands by sweat, bacteria, and zinc oxide dust. 

One would not expect to see observable releaser pheromone effects in humans, which are primarily behavioral and immediate. Despite the lack of evidence, numerous fragrances, or additives to fragrances, whose advertisements perpetuate the myth that an odor can make one irresistible to members of the opposite sex, have been, or are being sold. Studies conducted over the past two decades present evidence that humans emit primer pheromones, which can alter the length and timing of the menstrual cycle. The human axillae is a likely source of these chemosensory signals. The molecular identity and chemoreceptive and endocrine pathways by which they operate remain to be elucidated. 

BODY ODOR CHEMISTRY THE HUMAN AXILLAE AS A SOURCE OF HUMAN PRIMER PHEROMONES... 

Numerous studies with humans have examined the perception of odors collected on T-shirts and pads from the upper part of the body and the axillae (Russell, 1976 Doty, et al., 1978 Schleidt, 1980 Schleidt, et al., 1981). These odors allow individuals to identify their own smell as well as that of their spouse and close kin (Porter Moore, 1981 Cer-noch Porter, 1985 Porter, et al., 1986 Hepper, 1988). Analytical studies of axillary secretions collected from women across the menstrual cycle suggest changes in the ratios of both the odor-producing bacteria (Reilly, et al., 1996) and odorants (Preti, et al., 1987 Reilly, et al., 1996). These studies suggest that chemical cues from the axillae contain sufficient differences in the concentration of odorants to allow for discrimination of individuals and phase in the menstrual cycle in female subjects. 

Humans possess rich repositories of odors, one of which, the axillae, has been implicated as the source of semiochemical information. There is, however, no substantial body of evidence to allow one to conclude that releaser-pheromone effects can be ascribed to human odors. While there has been, and undoubtedly will continue to be, a stream of products claiming to use sex attractants and behavior modifiers isolated from humans, the absence of experimental data backing the efficacy of the claims may also be a trademark. Evidence addressing product efficacy may be presented in the form of personal testimonials, magazine/newspaper advertisements or the discoverer s appearance on a T.V. talk-show. Where data on such discoveries has appeared in patents, e.g., the copulin mixture, it can be subjected to an experimental protocol to determine validity. Eventually this will occur with other compounds claimed to be human pheromones and packaged for consumer-purchase caveat emptor). 

Human chemosensory cues produced in the axillae appear to act as primer pheromones that affect the human menstrual cycle. While data from studies demonstrating these effects have been criticized, they represent a valid scientific attempt to resolve interesting and important questions. The putative primer molecules produced in the axillae have the potential to alter menstrual-cycle length and timing, presumably by altering neuroendocrine levels. Consequently they represent a potential pathway for fertility enhancement and control, heretofore untried. 

The point that different human races possess their own characteristic odors is based on the fact that different ethnic groups have apocrine glands of different size. Thus, compared with the Europeans and Negroes, individuals of the Mongolian race possess only weakly developed apocrine and sebaceous glands, mainly in the axilla 117),... 

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