Nerve growth factor in the anterior pituitary: Localization in mammotroph cells and cosecretion with prolactin by a dopamine-regulated mechanism

Cristina Missale, Flora Boroni, Sandra Sigala, Alessandro Buriani, Michele Fabris, Alberta Leon, Roberto Dal Toso, Pierfranco Spano

Research output: Contribution to journalArticle

Abstract

Nerve growth factor (NGF) is well characterized for its neurotrophic actions on peripheral sensory and sympathetic neurons and on central cholinergic neurons of the basal forebrain. Recent evidence, however, has shown high levels of NGF to be present in a variety of biological fluids after inflammatory and autoimmune responses, suggesting that NGF is a mediator of immune interactions. Increased NGF serum levels have been reported in both humans and experimental animal models of psychological and physical stress, thus implicating NGF in neuroendocrine interactions as well. The possible source(s) and the regulatory mechanisms involved in the control of serum NGF levels, however, still remain to be elucidated. We now report the presence of both NGF gene transcripts and protein in the anterior pituitary. Immunofluorescence analysis indicated that hypophysial NGF is selectively localized in mammotroph cells and stored in secretory granules. NGF is cosecreted with prolactin from mammotroph cells by a neurotransmitter- dependent mechanism that can be pharmacologically regulated. Activation of the dopamine D2 receptor subtype, which physiologically controls prolactin release, resulted in a complete inhibition of vasoactive intestinal peptide- stimulated NGF secretion in vitro, whereas the specific D2 antagonist (-)- sulpiride stimulated NGF secretion in vivo, suggesting that the anterior pituitary is a possible source of circulating NGF. Given the increased NGF serum levels in stressful conditions and the newly recognized immunoregulatory function of this protein, NGF, together with prolactin, may thus be envisaged as an immunological alerting signal under neuronal control.

Original languageEnglish
Pages (from-to)4240-4245
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume93
Issue number9
DOIs
Publication statusPublished - Apr 30 1996

Keywords

  • D receptor
  • gp140(trk)
  • neuroimmune interactions
  • stress

ASJC Scopus subject areas

  • Genetics
  • General

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