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Biomedical subjects

M Ohneda

Publications and source records attributed to M Ohneda.

51 records · Page 3Linked to original sources
PubMed1990

Increased plasma glucagon-like immunoreactivity in dogs with ileojejunal transposition.

To elucidate hormonal and metabolic changes in intestinal adaptation, an experimental study was performed in dogs subjected to ileojejunal transposition. Fasting levels of blood glucose, plasma insulin and gastric inhibitory polypeptide (GIP) did not change significantly throughout 12 weeks. Plasma glucagon measured with an antiserum specific to the C-terminal portion of glucagon slightly increased and plasma total glucagon measured with a non-specific antiserum gradually increased. Glucose tolerance deteriorated at the 4th week in the transposed group. The response of plasma insulin and GIP to glucose in the transposed group did not differ from that of the sham operated group. Plasma glucagon increased significantly during glucose loading at the 12th week. The response of plasma total glucagon to glucose was most prominent, reaching a peak of 3,755 +/- 742 pmol/liter. The value was significantly increased, compared with that of the sham group or normal group (p less than 0.01). Insulin-induced hypoglycemia enhanced a larger increment of plasma total glucagon in the transposed group than in the sham group (p less than 0.05). At the 12th week plasma total amino acids were decreased and several amino acids were reduced. It is concluded that ileojejunal transposition elicited an exaggerated response of plasma total glucagon to glucose and several metabolic derangements and that the transposition offers an excellent model for hyperenteroglucagonemia.

Amino Acids↗
PubMed1989

Detection of immunoreactive endothelin in plasma of hemodialysis patients.

Two types of radioimmunoassay (RIA) methods for measuring endothelin (ET) in human plasma were developed. One was an extraction procedure using a Sep-Pak C18 cartridge, the other being a direct method. By the extraction method, plasma ET levels were lower than the detectable limit (7 pg/ml) in normal subjects and elevated in hemodialysis patients. The absolute values obtained via the direct method were 20-times higher than those from extraction. Gel-filtration experiments revealed that this discrepancy was mainly due to immunoreactive (IR-) endothelin-like substances of high molecular mass near 11.6 kDa (large IR-ET). Extraction of the peptide by the C18 cartridge could eliminate interference by large IR-ET and is important in the accurate measurement of ET concentrations in plasma.

Adult↗
PubMed1989

Response of gut glucagon-like immunoreactivity to hypoglycemia in dogs.

Previous studies demonstrated that insulin-induced hypoglycemia enhances glicentin secretion in piglets and prompted us to investigate the response of glucagon-like immunoreactivity (GLI) to hypoglycemia in dogs. Insulin hypoglycemia did not induce any rise of plasma total immunoreactive glucagon (IRG) measured by nonspecific antiserum to glucagon in normal or pancreatectomized dogs under anesthesia. In contrast, insulin-induced hypoglycemia clearly increased plasma total IRG in both normal and pancreatectomized dogs in a conscious state. Administration of acetylcholine resulted in an elevation of plasma total IRG, whereas epinephrine induced a slight increase in plasma total IRG. The infusion of alpha- or beta-adrenergic blockers did not affect the response of plasma total IRG to hypoglycemia, whereas atropine completely blunted the increase in plasma total IRG during insulin hypoglycemia. Similarly atropine abolished the rise of plasma total IRG during intravenous administration of 2-deoxy-D-glucose. It is concluded that hypoglycemia clearly enhances the secretion of GLI from the gut in dogs and that GLI secretion during hypoglycemia is modulated, at least in part, by the autonomic nervous system.

Acetylcholine↗
PubMed1989

Calcitonin gene-related peptide in the human hypothalamus.

Calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) in the human hypothalamus was investigated by radioimmunoassay and by immunocytochemistry. CGRP-LI was detected from two hypothalami obtained at autopsy (2.1 and 7.0 ng/g wet tissue) by radioimmunoassay. Reverse phase high performance liquid chromatography revealed that most of the CGRP-LI in the human hypothalamus was eluted in an identical position with synthetic human CGRP. For immunocytochemistry, human hypothalami obtained at autopsy were fixed and cryostat-sectioned at 40 microns. Free floating sections were immunostained with antibody to CGRP. CGRP-immunoreactive cell bodies were found in the supraoptic nucleus, paraventricular nucleus and infundibular nucleus. These findings indicate that CGRP exists in the cell bodies of the supraoptic nucleus, paraventricular nucleus and infundibular nucleus in the human hypothalamus and CGRP may play some roles in the endocrine and other functions of the human hypothalamus.

Aged↗
PubMed1989

Neuropeptide Y and blood pressure in haemodialysis patients.

To investigate the relationship between plasma neuropeptide Y (NPY) concentrations and blood pressure in haemodialysis (HD), we measured plasma immunoreactive neuropeptide Y (IR-NPY) concentrations and blood pressure before and after HD in 71 patients undergoing maintenance HD. Plasma IR-NPY concentrations were measured by radioimmunoassay after extraction with Sep-Pak C18 cartridges. We corrected the plasma IR-NPY values after HD by reference to the ratio of the plasma total protein levels before HD to the levels after HD, in order to exclude the influence of the haemoconcentration caused by HD. Plasma IR-NPY concentrations before and after HD in 71 patients undergoing maintenance HD were 413 +/- 94 pg/ml and 340 +/- 90 pg/ml (mean +/- SD), respectively. Plasma IR-NPY concentrations before HD in 28 hypertensive patients with HD (398 +/- 91 pg/ml) were not significantly different from those in 40 normotensive (427 +/- 98 pg/ml) and 3 hypotensive (372 +/- 21 pg/ml) patients with HD (P greater than 0.1). Plasma IR-NPY concentrations after HD in 9 patients whose systolic blood pressure fell more than 30 mmHg during HD (409 +/- 52 pg/ml) were significantly higher than those in the other patients (P less than 0.025). These findings suggest that the release of NPY is increased when the blood pressure falls during HD in patients undergoing maintenance HD.

Blood Pressure↗
PubMed1989

Neuropeptide Y- and somatostatin-like immunoreactivities in ganglioneuroma, ganglioneuroblastoma and neuroblastoma.

Neuropeptide Y (NPY)- and somatostatin (SS)-like immunoreactivities (LI) were investigated in tumor tissues of one ganglioneuroma (GN), 3 ganglioneuroblastomas (GNB) and one neuroblastoma (NB) by radioimmunoassay. NPY-LI was detected from all 5 tumor tissues (16.4-1247 pmol/g wet tissue). Sephadex G-50 column chromatography and reverse phase high performance liquid chromatography (HPLC) revealed that most of the NPY-LI in tumor extracts was eluted in an identical position to synthetic human NPY except one GNB (case 2). In this case, most of the NPY-LI was eluted in a higher molecular weight region than synthetic human NPY in Sephadex G-50 column chromatography and in a more hydrophobic position in HPLC. SS-LI was detected from 4 tumor extracts except one GNB (case 2) (21.3-787 pmol/g wet tissue). Sephadex G-25 column chromatography and reverse phase HPLC revealed that SS-LI in tumor extracts was eluted just after the void volume and then in the same positions as SS-28 and SS-14. These results suggest that NPY, SS-14 and SS-28 exist in tumor tissues of GN, GNB and NB, and most of the NPY-LI in one GNB was a higher molecular and more hydrophobic form of NPY-LI.

Chromatography, Gel↗
PubMed1989

Effect of porcine pancreastatin on endocrine function of canine pancreas.

Controversial results concerning the modulation of insulin release with pancreastatin prompted us to investigate the effect of this peptide upon the endocrine function of the pancreas using an in situ perfusion method in dogs. Administration of porcine pancreastatin into the pancreaticoduodenal artery in a dosage of 0.34 micrograms/kg of body weight during arginine infusion increased slightly plasma insulin and lowered minimally plasma glucagon in the pancreaticoduodenal vein. Pancreastatin infusion in a dosage of 500 ng/min did not modify glucose-induced insulin release and glucagon suppression by glucose. Theophylline infusion induced a slight increase in plasma insulin and glucagon in the pancreaticoduodenal vein. Pancreastatin infusion accelerated slightly these changes in plasma insulin and glucagon following theophylline infusion. From the present experiment it is concluded that porcine pancreastatin did not inhibit glucose-induced insulin release from the canine pancreas, inconsistent with the first report on insulin release from the rat pancreas. Alternatively, porcine pancreastatin rather stimulated insulin release during arginine infusion or following theophylline administration.

Animals↗
PubMed1988

Effect of glicentin-related peptides upon the secretion of insulin and glucagon in the canine pancreas.

In order to clarify responses of the endocrine pancreas to glicentin, four glicentin-related peptides were investigated in a local circulation preparation of the canine pancreas. These peptides were administered in a dosage of 200 pmole for 10 min into the pancreaticoduodenal artery under the continuous infusion of 0.5% arginine solution. In a group of six dogs, the administration of glicentin-related pancreatic peptide (GRPP) and glicentin 1-16 resulted in an increase in plasma insulin (IRI) and a decrease in plasma glucagon (IRG). In the other group of six dogs, the administration of glicentin 62-69 induced an increase in plasma IRI and a decrease in plasma IRG. Following the successive infusion of oxyntomodulin, both plasma IRI and IRG increased slightly. Porcine glucagon administered at the end of each experiment exerted a rise in blood glucose and plasma IRI in addition to an increase in plasma IRG. In comparison of the maximal responses of plasma IRI and IRG to these glicentin-related peptides, the administration of glicentin 1-16, 62-69 or GRPP elicited an increase in plasma IRI and a decrease in plasma IRG. In contrast, oxyntomodulin and glucagon increased both plasma IRI and IRG. The present study indicates that glicentin-related peptides, both the N- and C-terminal portions, affect the endocrine function of the pancreas and suggests that glicentin released by nutrient ingestion plays an important role in the enteroinsular axis.

Animals↗
PubMed1987

Increased plasma immunoreactive neuropeptide Y concentrations in phaeochromocytoma and chronic renal failure.

To investigate the clinical usefulness of radio-immunoassay of neuropeptide Y (NPY), we measured plasma immunoreactive neuropeptide Y (IR-NPY) concentrations in normal subjects (n = 21), essential hypertensive patients (n = 33), patients with phaeochromocytoma (n = 7), patients with chronic renal disease with serum creatinine levels of less than 1.9 mg/dl (n = 5) and patients with chronic renal failure whose serum creatinine levels were greater than or equal to 1.9 mg/dl (n = 18, eight without haemodialysis and 10 undergoing maintenance haemodialysis), by radio-immunoassay. Plasma IR-NPY concentrations in patients with phaeochromocytoma (577 +/- 256 pg/ml, mean +/- s.d.) were significantly higher (P less than 0.001) than those in normal subjects (151 +/- 28 pg/ml), essential hypertensive patients (177 +/- 49 pg/ml) and patients with chronic renal disease with serum creatinine levels less than 1.9 mg/dl (198 +/- 71 pg/ml). Plasma IR-NPY concentrations in patients with chronic renal failure (without haemodialysis: 330 +/- 63 pg/ml; undergoing maintenance haemodialysis: 374 +/- 80 pg/ml) were also high. These results suggest that NPY is useful as one of the tumour markers of phaeochromocytomas. However, this study revealed that patients with chronic renal failure, without phaeochromocytoma also have increased plasma IR-NPY concentrations.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Increases of neuropeptide Y-like immunoreactivity in plasma during insulin-induced hypoglycemia in man.

Neuropeptide Y-like immunoreactivity (NPY-LI) in plasma during insulin-induced hypoglycemia was measured in 4 healthy male volunteers. Plasma NPY-LI increased from 167 +/- 11 pg/ml to 247 +/- 25 pg/ml 30 min after the administration of insulin (0.1 U/kg body weight IV), reached the maximum (296 +/- 6 pg/ml) 45 min after the insulin, and then decreased. These results suggest that NPY is released into the systemic circulation during insulin-induced hypoglycemia in man.

Adult↗
PubMedDate not supplied

Calcitonin gene-related peptide-like immunoreactivities in pheochromocytomas.

Calcitonin gene-related peptide (CGRP) is reported to exist in high concentrations in plasma and tumor tissues of medullary thyroid carcinomas. CGRP-like immunoreactivity (LI) in tumor tissues of pheochromocytomas was investigated by radioimmunoassay. CGRP-LI in 9 pheochromocytomas ranged from 0.50 to 1240 ng/g wet tissue. Sephadex G-50 column chromatography revealed that most of CGRP-LI in tumor extracts was eluted in an identical position to synthetic human CGRP. Reverse-phase high pressure liquid chromatography revealed that CGRP-LI in tumor extracts was eluted in an identical position to synthetic human CGRP and in a more hydrophobic position. These results indicate that high concentrations of CGRP-LI also exist in tumor tissues of pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Porcine brain natriuretic peptide-like immunoreactivity in rat tissues.

The presence of immunoreactive porcine brain natriuretic peptide in rat tissues was studied with a specific radioimmunoassay for porcine brain natriuretic peptide-26. The cross-reactivity of the antiserum used was less than 0.001% with rat atrial natriuretic peptide, rat brain natriuretic peptide-32 and rat brain natriuretic peptide-45. Immunoreactive porcine brain natriuretic peptide was detectable in various tissues of the rat, and high concentrations of immunoreactive porcine brain natriuretic peptide were found in the brain and cardiac atrium, with the highest level in the hypothalamus (159 +/- 30 fmol/gram wet tissue, mean +/- SEM, n = 4). Reverse phase high performance liquid chromatography showed that the immunoreactive porcine brain natriuretic peptide of the whole brain and heart extracts eluted mainly at an identical position to synthetic porcine brain natriuretic peptide-26. These findings indicate that porcine brain natriuretic peptide-like substance, distinct from rat brain natriuretic peptide, is present in high concentrations in the rat brain and cardiac atrium.

Animals↗
PubMedDate not supplied

Human brain natriuretic peptide-like immunoreactivity in human brain.

The presence of immunoreactive human brain natriuretic peptide in the human brain was studied with a specific radioimmunoassay for human brain natriuretic peptide-32. This assay showed no significant cross-reaction with human alpha atrial natriuretic peptide, porcine brain natriuretic peptide or rat brain natriuretic peptide. Immunoreactive human brain natriuretic peptide was found in all 5 regions of human brain examined (cerebral cortex, thalamus, cerebellum, pons and hypothalamus) (0.6-6.7 pmol/g wet weight, n = 3). These values were comparable to the concentrations of immunoreactive alpha atrial natriuretic peptide in human brain (0.5-10.1 pmol/g wet weight). However, Sephadex G-50 column chromatography showed that the immunoreactive human brain natriuretic peptide in the human brain eluted earlier than synthetic human brain natriuretic peptide-32. These findings suggest that human brain natriuretic peptide is present in the human brain mainly as larger molecular weight forms.

Aged↗
PubMedDate not supplied

Melanin-concentrating hormone in the human brain.

The presence of human melanin-concentrating hormone (MCH) was studied in the human brain by radioimmunoassay and immunocytochemistry. Immunoreactive MCH concentrations in the human brain ranged from 0.07 to 19.7 pmol/g wet weight. High performance liquid chromatography of the hypothalamus showed a large immunoreactive peak in the position of human/rat MCH, which was eluted 9 min later than that of salmon MCH. Free-floating sections (40 microns) of the hypothalamus were immunostained. Positive MCH immunostaining was found in perifornical, tuberomammillary, and posterior nuclei. Numerous MCH-immunoreactive nerve fibers were observed throughout the hypothalamus. The presence of high concentrations of MCH in the human brain, in particular in the hypothalamus, suggests that MCH is a neurotransmitter, a neuromodulator, or a neurohormone in man.

Aged↗