Immunohistochemical evidence suggests intrinsic regulatory activity of human eccrine sweat glands

Immunohistochemistry of normal eccrine sweat glands was performed on paraff in sections of human skin. Immunoreactivity (ir) for neuron specific enolas e, S100 protein (S100), regulatory peptides, nitric oxide synthase type I ( NOS-I) and choline-acetyltransferase (ChAT) was found in small nerve bundle s close to sweat glands. In the glands, secretory cells were labelled with anticytokeratin antibody. Using antibodies to S100, calcitonin gene-related peptide (CGRP) and substance P (SP) a specific distribution pattern was fo und in secretory cells. Granulated (dark) and parietal (clear) cells were i mmunopositive for CGRP, and S100 and SP, respectively. Immunoreactivity was diffuse in the cytoplasm for CGRP and S100, and peripheral for SP. Myoepit helial cells were not labelled. Electron microscopy revealed electron dense granules, probably containing peptide, in granulated cells. Using antibodi es to NOS-I and ChAT, ir was exclusively found in myoepithelial cells. Immu noreactivity for the atrial natriuretic peptide was absent in sweat glands. These results provide evidence for the presence of both regulatory peptide s involved in vasodilation and key enzymes for the synthesis of nitric oxid e and acetylcholine in the secretory coil of human sweat glands. It is sugg ested that human sweat glands are capable of some intrinsic regulation in a ddition to that carried out by their nerve supply.