Explore the vast range of titles available.

The adenohypophysis of the white seabream (Diplodus sargus) was studied using histochemical and immunocytochemical techniques. The adenohypophysis was composed of rostral pars distalis, proximal pars distalis and pars intermedia. Prolactin (anti-chum salmon prolactin positive) and adrenocorticotropic (anti-human ACTH positive) cells were found in the rostral pars distalis. Prolactin cells were organized into follicles, while ACTH cells were arranged in cords around neurohypophyseal tissue branches that penetrated the rostral pars distalis. In the proximal pars distalis, somatotropic (anti-chum salmon and anti-gilthead seabream growth hormone positive), gonadotropic (anti-chum salmon β-gonadotrophin II and anti-carp β-gonadotrophin II positive, but anti-chum salmon β-gonadotrophin I negative) and thyrotropic (anti-human β-thyrotropin positive) cells were observed. Growth hormone cells were restricted to the dorsal and ventral part of the proximal pars distalis. They were clustered or surrounded the neurohypophyseal branches. Only one type of gonadotrophin cell was identified and they were clustered or isolated in the proximal pars distalis. Scattered groups of thyrotropin cells were located throughout the proximal pars distalis. In the pars intermedia somatolactin (anti-chum salmon and anti-gilthead seabream somatolactin positive) and melanotropic (anti-α-melanotropic hormone positive) cells were localized. In addition, gonadotrophin cells surrounded the pars intermedia or distributed evenly between somatolactin and melanotropic hormone cells. Somatolactin cells were periodic acid-Schiff negative and surrounded the neurohypophyseal branches intermingled with melanotropic cells. These cells were also immunoreactive to anti-human ACTH antiserum.[PUBLICATION ABSTRACT]

The activation of human granulocytes and invertebrate immunocytes was found to be suppressed by corticotropin (ACTH) and melanotropin (MSH). In spontaneously active granulocytes both neuropeptides caused significant conformational changes indicative of inactivity plus a reduction in their locomotion. Significant inactivation of human granulocytes by ACTH required 2 hr, that by MSH only 20 min. The addition to the incubation medium of phosphoramidon, a specific inhibitor of neutral endopeptidase 24.11, blocked inactivation of granulocytes by ACTH. Radioimmunoassay for MSH of supernatant fluids from granulocytes incubated with ACTH demonstrated a time-dependent increase in MSH. These data strongly indicate that the effect of ACTH is largely due to its conversion to MSH by granulocyte-associated neutral endopeptidase. Parallel experiments with immunocytes from the mollusc Mytilus edulis gave similar results, indicating the universality of this phenomenon. Our finding that the human immunodeficiency virus, among several viruses, induces ACTH and MSH production in H9 T-lymphoma cells suggests an important role of these neuropeptides in the immunosuppression characteristic of such infections.

α -Melanocyte stimulating hormone (α -melanotropin) immunofluorescence was observed in rat brain by means of a highly specific and well-characterized antibody. The hormone was contained in arcuate nucleus cell bodies and in varicose fibers. Dense populations of hormone-containing fibers were present in the septum, the nucleus interstitialis stria terminalis, and the medial preoptic, anterior hypothalamic, dorsomedial, and periventricular nuclei. Moderate numbers of fibers were seen in the paraventricular and arcuate nuclei, the amygdala, the region of the tractus diagonalis, the mammillary body, the central gray, the cuneiform nucleus, and the nucleus of the solitary tract. There is an interesting correlation of α -melanocyte stimulating hormone fibers with regions of noradrenergic axonal projections and terminal fields.

It is generally accepted that human β -melanocyte-stimulating hormone (hβ MSH) does not normally exist in humans but was merely an artifactually generated 22-amino acid peptide corresponding to a lipotropin (LPH) fragment (residues 35-56). We examined whether the shorter 18-amino acid peptide hβ MSH-(5-22) could be detected in some human tissues. Normal human pituitaries and hypothalami as well as corticotropin-secreting pituitary and nonpituitary tumors were extracted and chromatographed on Sephadex G-50, and the fractions were measured with two radioimmunoassays using either a COOH-terminal human γ LPH (hγ LPH) antiserum that recognized equally hγ LPH, hβ MSH, and hβ MSH-(5-22) or a mid-portion hγ LPH antiserum that recognized hγ LPH and hβ MSH but not hβ MSH-(5-22). Normal pituitaries and pituitary tumors contained a single immunoreactive material coeluting with hγ LPH. The hypothalami and the nonpituitary tumors all contained hγ LPH and a smaller molecular weight material that was only detected in the COOH-terminal hγ LPH radioimmunoassay; its elution volume (Ve/V, 0.75) was identical to that of hβ MSH-(5-22) but different from that of hβ MSH (Ve/V, 0.60); on reversed-phase HPLC, it coeluted with synthetic hβ MSH-(5-22) with a retention time different from that of hβ MSH. It is concluded that hβ MSH-(5-22) that corresponds to the 18-amino acid peptide hβ LPH-(39-56), flanked by two pairs of basic amino acids within the hβ LPH molecule, is a normal maturation product of proopiomelanocortin in human nonpituitary tissues.

Long-term ovariectomized (OVX) rats were injected in the third cerebral ventricle with 5 μ l of the globulin fraction of an antiserum raised against α -melanocyte-stimulating hormone (α -MSH) or an equal volume of the globulin fraction of normal rabbit serum (NRS). Immunoneutralization of brain α -MSH produced an increase in the area under the secretion curve of prolactin (Prl), the amplitude of Prl pulses, and mean plasma Prl (P < 0.01). In animals that had received two injections of NRS or anti-MSH and were subjected to a 2-min ether stress, Prl levels significantly increased within 5 minutes in the NRS-injected rats, whereas Prl levels in the antiserum-injected rats did not increase any further from the initially high baseline levels. The administration of antibodies against α -MSH produced a small increase (P < 0.05) in the area under the secretion of luteinizing hormone (LH) and mean plasma LH; however, the number of LH pulses was unaffected. We conclude that endogenous α -MSH of central origin is a physiological neuromodulator of release of Prl and LH in the OXV rat and is involved in the stress-induced release of Prl.

An antiserum to α -melanocyte-stimulating hormone (α -MSH) was found to contain antibodies to at least two types of determinants on the α -MSH peptide: one is present only on the free peptide, the other is shared with neurofilaments. Immunoblots from mouse brain showed the neurofilament crossreactivity to be located on proteins in the Mr140,000 range. The neurofilament-crossreactive portion of the antiserum could be selectively absorbed out with a cytoskeletal preparation, which abolished all affinity of the antiserum to the retina but did not affect the labeling pattern in the pituitary. Absorptions with desacetyl-α -MSH and corticotropin seemed to indicate that the determinant shared with neurofilaments is not located at either end of the α -MSH peptide, but somewhere in between. The immunohistochemical labeling of the retina with the α -MSH antiserum was compared to the labeling with monoclonal antibodies against Mr200,000 neurofilaments. In the adult retina the α -MSH-like immunoreactivity was found to be slightly more widespread; most consistently it was detectable in cell bodies of large ganglion cells, whereas the heavy neurofilament subunit was absent from somata and proximal axons of these cells. In the developing mouse brain, expression of the heavy subunit was found to lag 2-3 wk behind expression of the Mr140,000 proteins. This confirms previous reports of a more restricted distribution and late expression of high molecular weight neurofilaments as compared to the lower subunits.

The biosynthesis of corticotropin (ACTH1-39), β -endorphin [β (61-91)-lipotropin] and α -melanotropin in the toad intermediate lobe was studied by using immunoprecipitation procedures with antisera specific for these peptides. Intermediate lobes were pulse-incubated with [3H]phenylalanine and then chase-incubated for varying periods; the radioactive proteins were immunoprecipitated. Immunoprecipitates were separated by acidic urea or sodium dodecyl sulfate polyacrylamide gel electrophoresis. Evidence from the pulse-chase and sequential immunoprecipitation studies using antisera to ACTH and β -endorphin suggests that the toad intermediate lobe synthesizes two common precursors (apparent Mr32,000 and 29,500) containing both the ACTH and β -endorphin sequences. These precursors are processed to yield several forms of immunoreactive corticotropin (apparent Mr23,000, 21,000, 13,000, and 4300), immunoreactive endorphin (apparent Mr11,700 and 3500), and immunoreactive α -melanotropin. The 4300 Mrform of corticotropin and the 11,700 and 3500 Mrforms of endorphins were found to comigrate with synthetic ACTH1-39, β -lipotropin and β -endorphin, respectively, on both acidic urea and sodium dodecyl sulfate gels.

An indirect method of an enzyme-linked immunosorbent assay (ELISA) is described to assess the reactivity of antisera used for the identification of peptide hormone producing cells by immunocytochemistry. Compared with radioimmunoassay and immunodiffusion, the ELISA method has the advantages of simplicity and sensitivity and represents with the hormone adsorbed to a matrix a situation more or less comparable to that in tissue sections. It is concluded that specificity testing of antisera applied in endocrine immunocytochemical studies can best be achieved by application of the ELISA method in combination with appropriate tissue controls.

An analysis of the factors that influence the increase in plasma immunoreactive beta-melanocyte-stimulating hormone (beta-MSH) concentration in chronic renal failure showed that: (a) the increase correlated with the increase in serum creatinine concentrations; (b) beta-MSH was not cleared from the plasma by haemodialysis; (c) beta-MSH concentrations increased with length of time on dialysis and increased further after bilateral nephrectomy but there was no further increase with time; (d) beta-MSH levels decreased to normal after renal transplantation; and (e) beta-MSH was excreted in urine only when plasma levels rose to well above those of chronic renal failure (in Nelson's syndrome). These findings suggest that the kidney regulated plasma beta-MSH by a non-excretory mechanism and is the major site of beta-MSH metabolism.

Inflammation contributes to many chronic conditions. It is often associated with circulating pro-inflammatory cytokines and immune cells. GLP-1 levels correlate with disease severity. They are often elevated and can serve as markers of inflammation. Previous studies have shown that oxytocin, hCG, ghrelin, alpha-MSH and ACTH have receptor-mediated anti-inflammatory properties that can rescue cells from damage and death. These peptides have been studied well in the past century. In contrast, GLP-1 and its anti-inflammatory properties have been recognized only recently. GLP-1 has been proven to be a useful adjuvant therapy in type-2 diabetes mellitus, metabolic syndrome, and hyperglycemia. It also lowers HbA1C and protects cells of the cardiovascular and nervous systems by reducing inflammation and apoptosis. In this review we have explored the link between GLP-1, inflammation, and sepsis.