Gastric inhibitory polypeptide in newly diagnosed ketotic type I (insulin-dependent) diabetics.

Plasma concentrations of 5,000 daltons (5 kDa) immunoreactive gastric inhibitory polypeptide (IR-GIP) were measured before and up to 16 hours after the start of low-dose insulin treatment in newly diagnosed ketotic type I (insulin-dependent) diabetics. Nine patients were non-fasting. Before insulin treatment mean IR-GIP was 31 +/- 6 pmol/l (range 9-65 pmol/l).

Protonmotive stoichiometry of rat liver cytochrome c oxidase: determination by a new rate/pulse method.

The stoichoimetry of vectorial H+ ejection coupled to electron flow through the cytochrome c oxidase (EC 1.9.3.

The effects of glucose-dependent insulinotropic polypeptide infused at physiological concentrations in normal subjects and type 2 (non-insulin-dependent) diabetic patients on glucose tolerance and B-cell secretion.

The effects of porcine glucose-dependent insulinotropic polypeptide given by continuous intravenous infusion in normal subjects (n = 6) and Type 2 (non-insulin-dependent) diabetic patients (n = 6) have been investigated. The subjects were studied on 2 separate days after overnight fasts. On each day 25 g of glucose was infused from 0-30 min plus an infusion of either porcine glucose-dependent insulinotropic polypeptide (0.

Effect of porcine gastric inhibitory polypeptide on beta-cell function in type I and type II diabetes mellitus.

The effect of highly purified natural porcine GIP on C-peptide release was examined in six type I (insulin-dependent) diabetics (IDD) with residual beta-cell function, six type II non-insulin-dependent) diabetics (NIDD), and six normal subjects. All subjects were normal weight. From -120 minutes to 180 minutes glucose or insulin was infused IV to achieve a constant plasma glucose level of 8 mmol/L.

Enteropathic AIDS in Uganda. An endoscopic, histological and microbiological study.

Twenty-three Ugandan patients with enteropathic acquired immunodeficiency syndrome (AIDS, 'slim' disease) were studied. Upper gastrointestinal (GI) endoscopy, colonoscopy, biopsy, stool parasitology and culture were performed. Endoscopy revealed oral and/or oesophageal candidiasis in 22 patients.

The secretion of glucagon by transformed yeast strains.

Saccharomyces cerevisiae strains were transformed with plasmids coding for modified mating factor alpha 1 leader sequences followed by glucagon. Glucagon-containing peptides which were secreted into the fermentation broth were isolated and their amino acid sequences determined. The yeast strain transformed with the sequence coding for the complete mating factor alpha 1 leader sequence preceding the glucagon gene (MT556) secreted glucagon plus glucagon extended at its N-terminal by parts of the leader sequence.

Is there Ca2+(Sr2+)-3-hydroxybutyrate symport in rat-liver mitochondria? A reappraisal.

The observation in this laboratory that respiration and Sr2+ import were stimulated by the addition of 3-hydroxybutyrate to suspensions of N-ethylmaleimide-treated mitochondria respiring in state 6, after the addition of Sr2+, in a sucrose medium containing choline as substrate, led to the proposal by Moyle and Mitchell [(1977) FEBS Lett. 84, 135-140] that there is a Ca2+(Sr2+)-3-hydroxybutyrate symporter in rat liver mitochondria. However, experiments described in the present paper support a different interpretation.

Proton translocation by cytochrome oxidase in (antimycin + myxothiazol)-treated rat liver mitochondria using ferrocyanide or hexammineruthenium as electron donor.

When O2 was injected into an anaerobic suspension of valinomycin-treated rat liver mitochondria inhibited with rotenone, antimycin, and myxothiazol, a small amount of O2 (0.23-0.33 ng-atom of O/mg of protein) was reduced extremely rapidly (within the 2 s time-resolution of the oxygen electrode).

Renal catabolism of 125I-glicentin.

The renal catabolism of 125I-glicentin has been studied in vivo by the disappearance of this peptide from the plasma of bilaterally nephrectomized, ureteral-ligated, or normal rats and by using tubular microinfusion techniques. In addition the catabolism of glicentin by the isolated, perfused kidney has been studied. Results from in vivo studies demonstrated that half-disappearance time was lower in control (59.

Measurement of the proton-motive stoichiometry of the respiratory chain of rat liver mitochondria: the effect of N-ethylmaleimide.

The apparent proton-motive stoichiometry as measured by the oxygen-pulse technique in KCl medium is depressed by the rapid uptake of inorganic phosphate, unless endogenous phosphate is depleted or uptake is inhibited. In sucrose or choline chloride media, where the internal pH is more acid than in KCl media, uptake may be greatly diminished. In the absence of significant phosphate uptake, the observed stoichiometry of around 8, obtained with no added substrate or respiratory inhibitors, appears to be characteristic of NADH oxidation without significant participation of the proton-translocating NAD(P) transhydrogenase.

The effects of porcine GIP on insulin secretion and glucose clearance in the pig.

The present study was undertaken with the aims of studying the pharmacological effects and the pharmacokinetics of porcine GIP in pigs in vivo. Infusion of GIP and glucose resulted in a significant increase in the insulin release compared to the insulin release after glucose infusion in the control group. A significant increase in glucose clearance was also seen during GIP infusions.

Chemiosmotic coupling in cytochrome oxidase. Possible protonmotive O loop and O cycle mechanisms.

Using the principle of specific vectorial ligand conduction, we outline directly coupled protonmotive O loop and O cycle mechanisms of cytochrome oxidase action that are analogous to protonmotive Q loop and Q cycle mechanisms of QH2 dehydrogenase action. We discuss these directly coupled mechanisms in the light of available experimental knowledge, and suggest that they may stimulate useful new research initiatives designed to elucidate the osmochemistry of protonmotive oxygen reduction in cytochrome oxidase.

Structure-function relationships in glucagon. Re-evaluation of glucagon-(1-21).

Glucagon-(1-21) was prepared fully synthetically as well as by carboxypeptidase A digestion of natural porcine glucagon. Neither of the two preparations had glucagon agonistic effects with regard to receptor binding or adenylate cyclase activation in purified rat liver plasma membranes. Nor did these preparations contain lipolytic activity in isolated free fat cells.

The London marathon: 3 years in the running.

Over the 3 years from 1982 to 1984, a total of 34 patients were seen in the Accident and Emergency Department of St Thomas' Hospital, London, as a result of the London Marathon. Clinical details are discussed. Considering the number of annual runners who take part, the casualties from the finish of this event are low.

Immunoreactive gastric inhibitory polypeptide response to a meal during the first eighteen months after diagnosis of type 1 (insulin dependent) diabetes mellitus.

The changes in plasma concentrations of immunoreactive gastric inhibitory polypeptide (IR-GIP) in response to a standard meal were examined in 21 normal subjects and 15 Type 1 (insulin dependent) diabetic patients 7 days, 14 days, and 3, 6, 9, 12, and 18 months after time of diagnosis. During the first 4 tests significantly lower plasma IR-GIP concentrations were found in the diabetic patients after the standard meal. At 9 months and during the remaining tests there was no difference in IR-GIP concentrations between the diabetic and the normal subjects.

The isolation and sequencing of human gastric inhibitory peptide (GIP).

Human GIP 1-42 and fragments of human GIP corresponding to GIP 10-42, GIP 11-42, and GIP 17-42 were isolated from acid-ethanol extracts of human small intestines with the aid of an anti-GIP serum specific for the extreme C-terminal portion of the GIP molecule. The full sequence of human GIP has been established by Edman degradation of these peptides and fragments thereof by automatic gas-phase sequencing. Human GIP differs from porcine GIP at residues 18 and 34.

Cyclic-AMP-dependent phosphorylation of glicentin.

Highly purified glicentin, a 69-amino-acid-residue peptide isolated from porcine intestine that contains the full sequence of glucagon and is probably biosynthetically related to glucagon, is a substrate for cyclic-AMP-dependent protein kinase in a cell-free system. Glicentin-related pancreatic peptide (residues 1-30 of glicentin) and glucagon were not phosphorylated under the same reaction conditions. It is postulated that the serine residue at position 34 of glicentin (position 2 of glucagon), that is part of the sequence Lys.

Diminished immunoreactive gastric inhibitory polypeptide response to a meal in newly diagnosed type I (insulin-dependent) diabetics.

The release of immunoreactive gastric inhibitory polypeptide (IR-GIP) in response to a standard meal was examined in 10 normal subjects and 15 type I (insulin-dependent) diabetics 7 days (test I), 14 days (test II), and 3 months (test III) after time of diagnosis. During all three tests, the diabetics had significantly lower plasma IR-GIP concentrations than the controls from 15-90 min after the standard meal. The IR-GIP response in the diabetics measured as the integrated area under the response curve corresponded to 70% of that of normal subjects.

Gastric inhibitory peptide-like immunoreactivity in glucagon and glicentin cells: properties and origin. An immunocytochemical study using several antisera.

Although gastric inhibitory peptide (GIP) has never been detected outside the upper small intestine by immunochemical methods, GIP-like immunoreactivity has been demonstrated by immunocytochemistry in the glucagon/glicentin cells of pancreas, and gut. In the present study several GIP antisera (five polyclonal and one monoclonal) were tested on specimens from pancreas and intestines of several mammalian species, including man. Two of the polyclonal antisera and the monoclonal one stained cells in the upper small intestine only, while the other three also stained cells in the pancreas, ileum, and colon.

Inhibition of nicotinamide nucleotide transhydrogenase in rat liver submitochondrial particles by dicyclohexylcarbodi-imide and butanedione.

Nicotinamide nucleotide transhydrogenase in rat liver submitochondrial particles is inhibited by treatment with NN'-dicyclohexylcarbodi-imide or butane-2,3-dione. Both inhibitions are pseudo-first-order with respect to enzyme activity. The reaction order with respect to inhibitor is close to unity for butanedione, but is significantly lower than unity for dicyclohexylcarbodi-imide.