Effect of adrenal demedullation on neuropeptide Y content of the capsule/glomerulosa zone of the rat adrenal gland

Abstract

The capsule/glomerulosa zone of the adrenal gland is richly innervated by neuropeptide Y (NPY)-containing nerve fibers. The content and concentration of NPY in the capsule/glomerulosa zone of the female rat adrenal were determined by radioimmunoassay both in unoperated females (controls) and in operated ones, a week after in situ unilateral demedullation which excludes both the medulla and the fasciculata/reticularis zones. Demedullation induced a significant weight increase of the capsule/glomerulosa zone of the operated gland (compared to contralateral intact one) as well as of the medulla/fasciculata-reticularis zone of the contralateral intact one (compared to the corresponding part of the gland of controls). Both NPY content and concentration in the capsule/glomerulosa zone of the demedullated adrenal were significantly reduced in comparison with those in the corresponding part of the contralateral intact gland. NPY immunoreactive fibers, revealed by immunofluorescence, were present in the capsule/glomerular zone of both intact and contralateral demedullated adrenal gland. In the former, NPY fibers were regularly distributed in this part of the gland, while in the latter, some areas were devoid of immunoreactive fibers. NPY content, but not concentration, was increased in the medulla/fasciculata-reticularis zone of the contralateral intact gland. Present data support a dual origin for the NPY nerves present in the capsule/glomerulosa zone of the adrenal cortex: one part could arise from extra-adrenal site possibly the suprarenal ganglia while the other part could arise from intra adrenal ganglia cells which also contain NPY.