Apelin-immunoreactivity in the rat hypothalamus and pituitary

Neurosci Lett. 2002 Jul 26;327(3):193-7. doi: 10.1016/s0304-3940(02)00411-1.


With the use of an antiserum against human apelin-36, apelin-immunoreactivity (irAP) was detected in neurons and cell processes of the supraoptic nucleus (SO), paraventricular nucleus (PVH), accessory neurosecretory nuclei (Acc) and suprachiasmatic nucleus. Strongly labeled cells/processes were noted in the internal layer of the median eminence, infundibular stem, anterior and posterior pituitary. Double-labeling the sections with goat polyclonal neurophysin I-antiserum and rabbit polyclonal apelin-antiserum revealed a population of magnocellular neurons in the PVH, SO and Acc expressing both irAP and neurophysin I-immunoreactivity (irNP), the latter being a marker of oxytocin-containing neurons. By inference, the AP-positive but irNP-negative magnocellular neurons could be vasopressin-containing. The presence of irAP in certain hypothalamic nuclei and pituitary suggests that the peptide may be a signaling molecule released from the hypothalamic-hypophysial axis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apelin
  • Carrier Proteins / analysis*
  • Female
  • Hypothalamus / chemistry*
  • Immunohistochemistry
  • Intercellular Signaling Peptides and Proteins
  • Male
  • Microscopy, Confocal
  • Neurophysins / analysis
  • Pituitary Gland / chemistry*
  • Rats
  • Rats, Sprague-Dawley


  • Apelin
  • Apln protein, rat
  • Carrier Proteins
  • Intercellular Signaling Peptides and Proteins
  • Neurophysins