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Biomedical subjects

T Kodaira

Publications and source records attributed to T Kodaira.

At least 55 records · Page 3Linked to original sources

Distribution and regulation of mitochondrial hexokinase in rat submandibular gland.

1. In rat submandibular gland, hexokinase was distributed not only in cytosol fraction but also in mitochondrial fraction. 2. Glucose-6-phosphate and ATP were most effective substances on releasing hexokinase from mitochondria. However, all the hexokinase in mitochondria could not be extracted with these substances. 3. Concentrations of glucose-6-phosphate and ATP were decreased with the administration of epinephrine in vivo. 4. Increase of the amount of mitochondria-bound hexokinase was observed for 5 min with epinephrine administration, and it returned to the control level after 10 min. 5. In rat submandibular gland, mitochondrial hexokinase may reversibly bind to and release from mitochondria as observed in brain.

Adenosine Triphosphate↗

Exaggerated response of plasma glucagon-like immunoreactivity (GLI) to oral glucose in patients with reactive hypoglycemia.

In order to study the pathogenesis of reactive hypoglycemia, the responses of plasma glucose, IRI, glucagon immunoreactivity (GI) and total glucagon-like immunoreactivity (GLI) to 100 g oral glucose load were investigated in twenty-six patients of normal weight with reactive hypoglycemia. Of these patients, nineteen exhibited a diabetic OGTT curve. The findings in these patients were compared to normal control subjects (N = 20) and to disease-matched patients controls (N = 43). The psychological status was assessed by Cornell Medical Index Health Questionnaire in most of the subjects, who also received an x ray examination of the upper gastrointestinal tract. In addition, IVGTT was performed in the hypoglycemic patients. No apparent difference in plasma IRI response to oral glucose was observed between the hypoglycemic patients and their respective controls. Plasma total GLI concentrations were significantly increased during OGTT in both hypoglycemic groups. Following an oral glucose load, plasma GI levels were suppressed in the hypoglycemic groups to an extent similar to that in the control despite an apparent fall in their plasma glucose levels to the hypoglycemic range in the former. Radiological alterations in the upper gastrointestinal tract; deformity of the duodenal cap, gastric and/or duodenal ulcer, were found more frequently in the hypoglycemic groups. However, no characteristic change in personality was noticed in the patients. During IVGTT, neither plasma glucose nor total GLI level of the hypoglycemics differed from that of each control. The pathogenic factors responsible for reactive hypoglycemia will be discussed.

Glucagon↗

Production of antisera to des Asn28 Thr29 Homoser27-glucagon; the development of radioimmunoassay for total glucagon-like immunoreactivity in human plasma.

Antisera having a strong and strictly constant cross-reactivity for gut-GLI were raised in seven rabbits immunized with immunogen, a conjugate of BSA and des-Asn28, Thr29, Homoser27 -glucagon (CNBr-glucagon). All of the anti-CNBr-glucagon sera exhibited titer and affinity for glucagon sufficiently high enough to develop a sensitive radioimmunoassay. The relative crossreactivity of the antisera to gut-GLI was comparable to that of antiserum K-4023 which strongly crossreacted with gut-GLI. One of the anti-CNBr-glucagon sera, OAL-196, did not react with the glucagon 19-29 fragment at all. The intra- and inter-assay coefficients of variation were 3.8-5.0 and 6.0-7.3%, respectively, in the radioimmunoassay system for total GLI in human plasma using OAL-196. The fasting plasma total GLI was 374 +/- 18 pg/ml. The plasma total GLI during 50 g oral glucose load in normal subjects increased significantly, whereas the plasma IRG level measured with the anti-glucagon 19-29 serum, OAL-123, assay system was lowered. In the gastrectomized subjects, plasma total GLI measured with the present assay system elicited a marked increase following an oral glucose load. These results suggest that the radioimmunoassay using anti-CNBr-glucagon sera will be useful in measuring plasma total GLI.

Animals↗

Glucagon radioimmunoassay with use of antiserum to glucagon C-terminal fragment.

In this pancreatic-glucagon-specific radioimmunoassay we used C-terminal-region-specific antiserum. OAL-123, produced against a 19-29 C-terminal fragment of porcine glucagon. On measurement of pooled plasma the ranges for intra- and inter-assay coefficients of variation were 4.8-8.1% and 7.5-10.7%, respectively. The concentration of immunoreactive glucagon in plasma of healthy subjects, as measured with the OAL-123 assay system, was 87.9 (SD 23.8) ng/L. Measurement of the same plasma samples with the 30K assay system (30K being an antiserum highly specific for pancreatic glucagon) showed a comparable value, 86.2 (SD 26.3) ng/L. We followed changes in human and dog plasma immunoreactive glucagon concentrations on arginine infusion and after glucose load, using the OAL-123 and the 30K assay systems, with identical results. Combining other results of comparative immunochemical characterization of the OAL-123 and 30K assay systems, we confirmed that the antisera raised against the C-terminal fragment of glucagon can be used in radioimmunoassay of pancreatic glucagon.

Amino Acids↗

A study of the physiological role of glucagon. Passive immunization with antiserum specific for pancreatic glucagon in rats.

To investigate the physiological role of glucagon in the maintenance of euglycemia, the effect of the neutralization of glucagon by an antiserum specific for glucagon on blood glucose and C-peptide immunoreactivity (CPR) levels was studied in the basal as well as in the hyperglucagonemic states caused by hypoglycemia or an intravenous infusion of arginine in rats. The antiserum employed in this study was raised in rabbits by subcutaneous injection as a conjugate of BSA and the C-terminal fragment of glucagon. Since the antiserum was found to contain 896 ng/ml of antibody-bound glucagon, the antigen-stripped glucagon antibody was prepared. Its affinity constant and binding capacity were 2.57 x 10(10) M-1 and 147 nM, respectively. After the administration of 1 ml of the antiserum in 24-hr-fasted rats, no free immuno reactive glucagon (IRG) was detected during the experiment for 60 min. Likewise, antiserum treatment prevented a rise in the plasma IRG level following an arginine infusion and insulin-induced hypoglycemia. Plasma CPR levels tended to be lower in antiserum-treated rats than in the control in any conditions covered by the present study. However, changes in blood glucose levels the both groups were comparable. These results demonstrate that in the presence of glucagon antibodies euglycemia can be maintained with a reduced supply of insulin.

Animals↗