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.
Subject(s)
Animals , Humans , Rats , Growth Hormone , Hypothalamus , Immunohistochemistry , In Situ Hybridization , Ions , Pituitary Gland , Protein Isoforms , RNA, Messenger , Sodium-Calcium Exchanger , Supraoptic NucleusABSTRACT
Metallothionein (MT) family, intracellular zinc binding proteins, has been suggested to play an important regulatory role in zinc metabolism. The present study utilized light and confocal microscopic methods to investigate the expression pattern of MT-1, 2 and to determine the distribution and extent of colocalization of MT-1, 2 relative to subpopulations of S100 positive folliculostellate (FS) cells and somatotrophs in normal rat anterior pituitary. By light microscopy, MT-1, 2 immunoreactivity was observed both in pars intermedia and pars distalis of anterior pituitary. Confocal microscopy revealed that most MT immunoreactivity was colocalized in S100 positive FS cells, not in somatotrophs. This is the first report that FS cells in pars distalis contain MT-1, 2. These results suggest that MT family may be involved in regulation of hypophyseal endocrine functions and can be used as new markers of FS cells.
Subject(s)
Animals , Humans , Rats , Carrier Proteins , Immunohistochemistry , Metabolism , Metallothionein , Microscopy , Microscopy, Confocal , Pituitary Gland, Anterior , Somatotrophs , ZincABSTRACT
Ghrelin is a recently identified member of growth hormone secretagogue, which is synthesized as peptide of 28 amino acids in stomach, pituitary and intestines. Ghrelin controls food intake, and induces gastric acid secretion. It has been reported that synthesis and secretion of ghrelin changes according to age of animals. In this study, in situ hybridization technique with digoxigenin-labeled oligonucleotide probe is applied to elucidate the developmental change of ghrelin mRNA expression pattern in rat stomach. Ghrelin mRNA positive cells first appeared in stomach of 9 day rats, mainly in base of gastric glands. It showed the highest density and spread to neck area of the gastric gland in 6 week rats. Number of positive cells decreased significantly in 18 months. Most of ghrelin mRNA positive cells were found as closed-type endocrine cells in fundus area. These results suggest that ghrelin expression may be involved in development and ageing process.