Immunoreactivity to glial cell line-derived neurotrophic factor and its receptors in the trout pancreas: a further endocrine-exocrine relationship?
Glial cell line-derived neurotrophic factor (GDNF) is a growth factor promoting the survival of several neuronal populations in the central, peripheral and autonomous nervous system. Outside the nervous system, GDNF functions as a morphogen in kidney development and regulates spermatogonial differentiation. GDNF exerts its roles by binding to glial cell line-derived neurotrophic factor receptor (GFR) a1, which forms a heterotetramic complex with rearranged during transfection (RET) proto-oncogene product, a tyrosine kinase receptor. In this study we report the presence of GDNF-, RET- and GFRa1-like immunoreactivity in the pancreas of juvenile trout. GDNF immunoreactivity was observed in the islet cells, while GFRa1- and RET- immunoreactivity was observed in the exocrine portion. These findings suggest a paracrine role of GDNF towards exocrine cells showing GDNF receptors GFRa1 and RET. The relationship could reflect physiological interactions, as previously indicated in mammalian pancreas, and/or a trophic role by endocrine cells on exocrine parenchyma, which shows a conspicuous increase during animal growth.
Lucini
Carla
C
Maruccio
L
L
Antonucci
R
R
Castaldo
L
L
D000818:Animals; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000032:analysis*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000032:analysis*; D007124:Immunoenzyme Techniques; D007515:Islets of Langerhans / Q000737:chemistry; D010179:Pancreas / Q000737:chemistry*; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis*; D014337:Trout / Q000378:metabolism*
D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D020794:Receptor Protein-Tyrosine Kinases