Expression of NCX and NCKX Isoforms mRNAs in Rat Pituitary Gland / 대한해부학회지

ABSTRACT

Na(+)-Ca(2+) exchanger plays a fundamental role in controlling the changes in intracellular concentration of Na(+) and Ca(2+) ions. Two different families of Na(+)-Ca(2+) exchanger, NCX (K(+)-independent Na(+)-Ca(2+) exchanger) and NCKX (K+-dependent Na(+)-Ca(2+) exchanger), are known and each family includes several isoforms. But little is known about their expression in pituitary gland. In this study, in situ hybridization with digoxigeninlabeled riboprobe and double-labeled experiments with immunohistochemistry were applied to investigate the expression of NCX and NCKX mRNAs and their distribution in normal rat pituitary gland. NCX2 mRNA hybridization signals were expressed in pars distalis, while both NCX2 and NCKX2 mRNAs expression were strongly observed in pars nervosa. NCX2 and NCKX2 mRNA were also expressed in supraoptic nucleus of hypothalamus. In pars distalis, 68.2% of growth hormone secreting cells was colocalized with NCX2 mRNA, whereas NCX2 mRNA was not found in S100 positive folliculostellate cells. These results suggest that NCX2 in pars distalis and NCX2 and NCKX2 in pars nervosa appear to be involved in endocrine function of pituitary gland.