Morphological evidence of endogenous digitalis-like substance (EDLS) in the rat and macaque hypothalamus, using digoxin-immunohistochemistry.

Morphological investigation of the endogenous digitals-like substance (EDLS) characterized as a natriuretic humoral agent has not been carried out to date; but EDLS can be detected indirectly by immunohistochemistry using cross-reactivity with digoxin-antibody. In this report, the brain and other organs of the rat and macaque were immunostained using commercially supplied digoxin-specific antibodies. The immunoreactive substances were mainly observed in the neurons of hypothalamic paraventricular and supraoptic nuclei, and varicose fibers in some areas of the hypothalamus and infundibulum. No immunopositive substances were detected in the pituitary anterior lobe, adrenal gland, or kidney of the rat.