Gene Expression Patterns of Pro-opiomelanocortin-processing Enzymes PC1 and PC2 During Postnatal Development of Rat Corticotrophs

Abstract

We examined the expression and localization of the prohormone convertases, PC1 and PC2, in the anterior pituitary cells of developing rats by a double staining procedure using in situ RT-PCR and an immunofluorescence technique. In the adult, both PC1 mRNA and PC2 mRNA were expressed in corticotrophs, gonadotrophs, thyrotrophs, and mammotrophs. These cells, except for corticotrophs, had previously been considered to be ones in which proprotein processing does not take place, but both PC1 and PC2 may be necessary to process other proteins, such as granin family proteins, having proteolytic cleavage sites and located in secretory granules of the above trophs. In addition, no PC1 or PC2 mRNA was expressed in somatotrophs, which is consistent with the fact that somatotrophs do not contain these granins. In addition, 7B2 mRNA was expressed in these PC2-positive trophs, suggesting that there is a functional relationship between PC2 and 7B2 proteins. We found that alpha-MSH was expressed in the corticotrophs of the postnatal rat and that the number of alpha-MSH-immunopositive corticotrophs decreased as development proceeded. Because the changes in the pattern of POMC processing are considered to depend on the relative expression levels of PC1 and PC2, PC1 and PC2 mRNAs were examined in corticotrophs during postnatal development. We found a decrease in the number of PC2 mRNA-positive cells, which coincided with one in the number of alpha-MSH-immunopositive corticotrophs, as postnatal development proceeded. Our present data demonstrate that the alpha-MSH production varies directly in accordance with the expression of PC2. We also discuss the possible significance of alpha-MSH production during the postnatal period.

The spatial and temporal expression of delta-like protein 1 in the rat pituitary gland during development

“…For staining of Dlk1, the sections were then treated for antigen retrieval by heating in a retrieval solution (1 mM EDTA in Milli-Q) at 120°C for 3 min in an autoclave (Sanyo, Osaka, Japan), washed three times with PBS, blocked with 1% BSA-PBS for 1 h, and immunolabeled by the immunoXuorescence method as described previously (Tanaka et al 1997). The sections were incubated overnight with chicken anti-bovine Dlk1 (1:2,000) and guinea pig anti-amidated joining peptide (JP) (ST-3; 1:2,000; Tanaka and Kurosumi 1992), goat antihuman thyroid stimulating hormone (TSH ; 1:2,000; Biogenesis, New Fields, UK), rabbit anti-rat TSH (1:2,000; supplied by Prof. K. Wakabayashi), rabbit anti-rat prolactin (PRL; 1:1,000; Kato et al 2004), guinea pig anti-human GH (1:2,000; Kato et al 2004), mouse monoclonal antibody against ovine luteinizing hormone (LH ; 1:1,000; Uehara et al 2001), or mouse monoclonal antibody against S-100 protein (Immuno Biological Laboratories, Fujioka, Japan), followed by a 2-h incubation with indocarbocyanine (Cy3)-labeled aYnity-puriWed donkey anti-chicken IgY (1:400; Jackson Immunoresearch), Xuorescein isothiocyanate (FITC)-labeled donkey anti-guinea pig IgG (1:400; Jackson), FITC-labeled donkey anti-mouse IgG (1:400; Jackson), Alexa 488-donkey anti-rabbit IgG (1:200; Molecular Probes, Eugene, OR, USA) or Alexa 488-donkey anti-goat IgG (1:200; Molecular Probes). For nuclear counterstaining, 4Ј, 6-diamidino-2-phenylindole (DAPI) was included with the secondary antibody solution.…”

Non-peptide ligands in the characterization of peptide receptors at the interface between neuroendocrine and mental diseases

“…Some of those have been radio-labeled for in vivo imaging. Clinical trials have been performed for ligands at CRF1 receptors [39,[42][43][44][45][46][47], at orexin receptors [48,49], at the NPY receptors [50,51], the opioid receptors [52], melanocortin -4-receptors (MC4-R) [53][54][55], melanin concentrating hormone receptors (MCH1-R) [56] and growth hormone secretagogue receptor 1 (ghrelin; GHS1-R) [57,58].…”

“…PC1 in corticotroph cells supplies ACTH-related peptides (ACTH, ß-lipoprotein (LPH) and a K-peptide) in pars anterior distalis of the pituitary gland. In melanotrophs of the pars intermedia PC1 and PC2 reveal predominantly α-MSH-related peptides (α-MSH, corticotrophin like intermediate peptide; CLIP) as well as LPHprocessed to β-endorphin [55]. PC2 has been recognized to be responsible for the formation of the α-, ß-and y MSH [133].…”

Expression of a mammalian aquaporin 3 homolog in the anterior pituitary gonadotrophs of the tree frog, Hyla japonica

“…To identify the pituitary cells, we employed mouse monoclonal antibody against the bullfrog luteinizing hormone β-subunit (LHβ) (Park et al 1987), mouse monoclonal anti-rat PRL (Chemicon, Temecula, CA, USA), guinea pig anti-human growth hormone (GH) (Kato et al 2004), guinea pig anti-bullfrog adrenocorticotropin (ACTH) 1-39 ) and goat anti-human thyroid-stimulating hormone (TSH) β-subunit (Biogenesis, New Fields, UK).…”