Blood vascular architecture of the rat extra-adrenal cortical body: a scanning electron microscopic study of corrosion casts.

A well developed extra-adrenal cortical body with an axis of 200-700 micron was found in eighteen of thirty adult male Wistar rats under a stereomicroscope. All eighteen bodies were located between the kidneys. Blood vascular beds of sixteen of the eighteen bodies were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The extra-adrenal cortical body was found to contain remarkably numerous capillaries which anastomosed with each other to form a conglomerated network; it received one afferent vessel and issued one to three (usually, one) efferent vessels. The blood capillaries were of sinusoidal and uniform calibers, and resembled those of the adrenal cortex. The network with an axis of 300-700 micron possessed a typical, deep efferent rootlet which corresponds to the central vein of the adrenal gland. Histological examination of the two bodies treated with Orth's or Helley's fixative confirmed that they consisted of non-chromaffin cells similar to those of the adrenal cortex. These findings suggest that in the rat, the extra-adrenal cortical bodies persist throughout life, actively producing cortical hormones.