THE ROLE OF THE MYOEPITHELIUM OF THE HUMAN APOCRINE SWEAT GLAND

[摘要] The role of the myoepithelium of the axillary apocrine sweat gland in man was investigated. Evidence was cited from the literature and from exptl. studies which indicates that myoepithelium is contractile and that it delivers preformed apocrine sweat to the skin surface. In summary the supportive evidence is 1. Myoepithelium is a sheath which selectively invests the apocrine tubules. Histo-logically it is a type of smooth muscle supplied by adrenergic fibres of the autonomic nervous system. From the physiologic standpoint the apocrine gland can be shown to be a reservoir of sweat, which once emptied requires hrs. before further sweating can be induced. The mechanical, thermal, electrical, and pharmacologic stimuli which ordinarily initiate contraction of smooth muscle also will induce apocrine sweating. Peristaltic waves may be seen in the apocrine tubules in vivo after appropriate stimulation. It is postulated that apocrine sweat gland function in man is divided into 2 phases: (a) Apocrine secretion, a continuous low-grade secretory activity of the tubular cells under hormonal control, and susceptible to the effect of intraluminal pressure. (b) Apocrine sweating, the delivery of preformed sweat to the skin surface as a result of peristaltic waves produced by contractions of the myoepithelium. The myoepithelium may respond to mechanical stimulation (friction of motion, stretch reflex from overfilling of gland), neural stimuli (adrenergic fibers), or humoral (circulating epinephrine) stimuli.