Search Results - (Author, Cooperation:N. G. Seidah)

2012-12-14

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Automation ; Drug Delivery Systems ; *Drug Design ; Female ; *Ligands ; Male ; Mice ; Mice, Inbred C57BL ; Models, Theoretical ; Pharmacological Phenomena ; Reproducibility of Results

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We observed the presence of the novel pituitary protein „7B2” and its release in the bovine adrenal medulla. The 7B2 concentration (mean ± SEM) in extracts of the bovine adrenal medulla was 952 ± 155 pg/mg tissue (n = 6). 7B2 was distributed in the chromaffin granule fraction prepared from the bovine adrenal medulla and was released by high K+ and/or nicotine from cultured cells of the bovine adrenal medulla. Co-release of 7B2 with catecholamine induced by nicotine from the cultured bovine chromaffin cells was also observed. In an analysis of the bovine adrenal medulla chromaffin granule fraction on gel permeation chromatography, there was a major peak with an apparent molecular weight of 45,000, whereas a major peak with an apparent molecular weight of 20,000 was found in that on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On reverse-phase HPLC, a major peak with a retention time of 35 min was observed in the bovine chromaffin granule fraction and in the bovine anterior pituitary extract. These findings indicate that 7B2 is a secretory protein in the bovine adrenal medulla. The possibility that 7B2 might be released with catecholamine, possibly in response to stress, warrants investigation.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Starting from an HC1/acetone extract of frozen human pituitaries, an initial ion-exchange fractionation on CM-cellulose was performed as previously described for the purification of human -LPH and -endorphin9. The unretained peak was further fractionated by gel chromatography on Sephadex G-75. ...

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1432-119X

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary The distribution pattern of CPP-containing neurons and fibers in the human pituitary and hypothalamus was studied with a specific antiserum to human CPP and the unlabeled antibody technique. Immunoreactive CPP was found in the magnocellular neurons of the supraoptic nucleus (SON), the paraventricular nucleus (PVN) and in neurons scattered in the supraoptic hypophyseal tract. CPP-containing parvocellular neurons were found in the suprachiasmatic nucleus (SCN). The CPP-containing fibers from the magnocellular neurons formed a tract coursing through the median eminence and the pituitary stalk to the posterior lobe of the hypophysis. In contrast, no such fibers from the SCN projected to SON, PVN and the median eminence. This pattern is identical to that of vasopressin and its associated neurophysin-containing neurons and fibers and strongly supports the concept that CPP is a part of the common precursor for vasopressin and neurophysin II. The biological importance of human CPP other than being a precursor fragment remains to be elucidated.

Electronic Resource

1573-2568

gastrointestinal tract ; pancreas ; 7B2 ; radioimmunoassay ; gel chromatography

Springer Online Journal Archives 1860-2000

Medicine

Abstract The distribution of a novel pituitary protein (7B2) was determined in the gastrointestinal tract and pancreas of four mammalian species (man, pig, guinea pig, and rat) by a specific radioimmunoassay. The highest concentrations of cross-reacting immunoreactive 7B2 (IR-7B2) were observed in the pancreas and the proximal gut (antrum or duodenum). While the intestinal concentrations varied widely among species, pancreatic IR-7B2 concentrations appeared to be similar in all four species. In the rat, pancreatic islets were found to contain high concentrations of IR-7B2 (5.73± 0.14 fmol/islet, mean± sem). Neonatal capsaicin treatment and enteric nerve section did not affect the concentrations of IR-7B2 in the rat intestine. Layer separation of human gut showed that IR-7B2 is mainly (71± 8%) present in the epithelial fraction. Chromatographic analysis of intestinal and pancreatic extracts from the four species on Sephadex G-100 showed the presence of two immunoreactive peaks at Kav 0.3 and 0.6, but there were both inter- and intraspecies variations in the proportions of the larger and smaller molecular forms.

Electronic Resource

1573-4919

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Medicine

Summary Studies of lipotropins, melanotropins and endorphins on one hand, and of adrenocorticotropin on the other, has given rise to the concept of a multipotent precursor molecule recently renamed proopiomelanocortin. The preferential sites of cleavage of the precursor to produce its biologically active components are made of pairs of basic amino acid residues as described for the biosynthesis of beta-MSH and pro-insulin. Such structure is also found in other pro-hormone molecules. Pulse chase experiments and secretory studies carried out in both anterior and intermediate lobes of rat pituitary glands revealed the transformation of different forms of the precursor into different end-products, the anterior lobe producing preferentially ACTH and beta-LPH while the intermediate produces mainly alpha-MSH and beta-endorphin. The multiple forms of precursors seem to differ in their carbohydrate content althouth at least two different gene products are still possible. The presence of similar peptides in the hypothalamus makes it highly probable that neuropeptides are biosynthesized with similar process. Thus the model of beta-LPH precursor, proposed as early as in 1967, is now applicable to the biosynthesis of all other neuropeptides. Major advances in this field are expected in the 1980's.

Electronic Resource

1432-1424

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Summary The equation for steady-state movement of ions of one kind through planar membranes has been solved. Numerical results are given, as well as profiles of potential, field and concentration. For small deviations from the equilibrium potential, an essentially constant intrinsic membrane conductance is obtained, which can be calculated from equilibrium properties. For larger deviations from equilibrium, the intrinsic membrane conductance is still essentially constant for symmetrical interfacial concentrations of the permeable ion, but varies significantly with potential for asymmetric interfacial concentrations, especially if these concentrations are small. In the latter case, one can often use the constant field approximation, for which explicit expressions are presented.

Electronic Resource

1432-1424

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Summary Transport of membrane-permeable ions through a hydrophobic membrane separating two aqueous phases is treated within the framework of the Poisson-Nernst-Planck equations. Specifically considered are transport through the stagnant (Nernst) and space charge (Gouy-Chapman) layers in the aqueous solutions and partition equilibrium or first-order phase transfer kinetics at the water/membrane interfaces. In all cases the calculated conductance is found to reach a maximum value at high ionic concentrations.

Electronic Resource

1432-1424

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Summary The admittance of a membrane permeable only to ions of one kind has been derived using the time-dependent Poisson-Nernst-Planck formalism. The effects of double layer charges, of slow phase transfer kinetics, of adsorption and of diffusion in the aqueous phases adjacent to the membrane, have been included explicity. As numerical example, the admittance in the totally symmetrical case of zero direct voltage and zero direct current has been calculated. It is shown that an approximation based on the constant field assumption leads to perfectly acceptable results under conditions in which the usual steady-state constant field approximation is applicable. In the resulting equivalent circuit, ion transport through the membrane is represented by a single resistance only, which greatly facilitates the analysis. The admittance exhibits a striking analogy with that of the metal/solution interface.

Electronic Resource

1432-1424

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Electronic Resource

1432-0878

7B2 polypeptide ; Gastro-intestinal tract ; Endocrine cells ; Immunohistochemistry ; Rat

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Immunoreactivity to the polypeptide designated “7B2” recently isolated from human and porcine pituitary glands, appears to be consistently confined to neuroendocrine and endocrine cells in various tissues. In rat gut, immunoreactive 7B2 was found in endocrine-paracrine cells. Highly labeled cells were found in the antrum of the stomach and, cells with lower concentrations, in the fundus, duodenum, jejunum and ileum. Except for a few cells which were simultaneously positive for 5-hydroxytryptamine, and a few others showing Grimelius's reaction, “7B2” cells do not exhibit argentaffin and/or argyrophil character. The 7B2 polypeptide seems to be distributed amongst several different types of endocrine cells in the gut.

Electronic Resource

1432-0878

Polypeptide 7B2 ; Adenohypophysis ; Secretion ; Immunocytochemistry ; Rat

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary A highly conserved polypeptide termed “7B2”, isolated from human and porcine pituitaries, has been reported by immunoreactivity to be distributed in various organs. However, the highest concentration has been found in the pituitary as demonstrated by a specific radioimmunoassay. In order to determine the type of cells within the pituitary that contain 7B2 and to analyse its intracellular localization, specific immunocytochemistry techniques (unlabeled antibody, peroxidase-antiperoxidase) were used both for light and electron microscopy. Immunocytochemistry of both expiants and monolayer-cell cultures of the adenohypophysis was studied. Immunoreactivity to 7B2 has been found in 21.9% of the total number of cells. After simultaneous staining of serial sections with appropriate antibodies, 7B2 was found to be colocalized with β-LH/β-FSH in gonadotrophs and with β-TSH in thyrotrophs. In situ immunocytochemistry at the electron-microscopic level showed that immunoreactive 7B2 is compartmentalized within secretory granules. The small (130 to 250 nm) but not the large granules (400 to 700 nm) were labeled in gonadotroph-like cells and small granules (90 to 150 nm) were also labeled in thyrothrophlike cells. Study of the gonadotrophs in cell culture after Zamboni's fixation revealed weak to moderate immunoreaction in rough endoplasmic reticulum. The current findings as well as previous data indicate that 7B2 is synthesized, stored and possibly released from the adenohypophysis similarly to many other secretory products.

Electronic Resource

1432-1777

Springer Online Journal Archives 1860-2000

Biology

Medicine

Electronic Resource