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Biomedical subjects

D Bataille

Publications and source records attributed to D Bataille.

At least 109 records · Page 6Linked to original sources
PubMed1981

"Enterolglucagon': a specific effect on gastric glands isolated from the rat fundus. Evidence for an "oxyntomodulin' action.

A newly isolated porcine glucagon-like biologically active intestinal peptide ("enteroglucagon') has been tested for its ability to stimulate the cyclic AMP system present in different tissue preparations from the rat: membranes prepared from liver or from isolated fundic glands as well as intact glands isolated from either the fundus or the antrum. Enteroglucagon (EG) was about 10 times less potent than pancreatic glucagon (G) in liver membranes, whereas it was about 20 times more potent than G in fundic membranes as well as in fundic glands, where it acts at doses as low as 3 X 10(-10) M. EG and G were practically ineffective in antral glands. It is concluded that EG is an "under-glucagon' in rat liver, whereas it is a "super-glucagon' in rat fundic glands. Accordingly, we propose to call this peptide "oxyntomodulin'.

Adenylyl Cyclases↗
PubMed1981

Bioactive enteroglucagon (oxyntomodulin): present knowledge on its chemical structure and its biological activities.

A bioactive form of enteroglucagon has been isolated from porcine jejuno-ileum according to its glucagon-like effect in liver. Enzymatic digestion followed by HPLC, dansylation and partial sequence analysis strongly suggests that this peptide contains the glucagon molecule (1--29) elongated at the C-terminal end by the octapeptide Lys-Arg-Asn-Lys-Asn-Ile-Ala-COOH and possibly modified in the N-terminal region. A specific action of bioactive enteroglucagon, increase in cAMP, has been found in the acid-secreting fundic part of the rat stomach. The term "oxyntomodulin" is therefore proposed to describe this peptide.

Amino Acid Sequence↗
PubMed1981

Secretin binding sites coupled with adenylate cyclase in rat fundic membranes.

Specific binding sites for secretin have been identified in rat fundic membranes, using 125I-secretin. The binding was saturable, reversible, time and temperature dependent. Optimal pH for binding was around 7-7.5. Scatchard plots were compatible with the existence of 2 classes of receptors; the first class with a high affinity for secretin (apparent Kd of 4 x 10(-10) M) and a low binding capacity (150 fmol per mg membrane protein, i.e., 4,500 high affinity sites/cell) and a class of receptors with a lower affinity (Kd of 3 x 10(-9) M) and a higher binding capacity (580 fmol per mg membrane protein i.e., 17,400 sites/cell). Glucagon, gastric inhibitory polypeptide and somatostatin had no-effect on secretin binding. In contrast, VIP inhibited 125I-secretin binding and stimulated adenylate cyclase activity, in both cases at a 200-times lower potency than secretin (ID50 and Ka = 2 x 10(-7) M VIP). The properties of these secretin receptors strongly support the concept that secretin acts as a regulatory peptide on the rat gastric epithelium.

Adenylyl Cyclases↗
PubMed1980

Evidence for a cyclic AMP system highly sensitive to secretin in gastric glands isolated from the rat fundus and antrum.

The effects of secretin and vasointestinal peptide (VIP) on the production of cyclic AMP have been studied in gastric glands isolated by means of EDTA from rat fundic and antral mucosa. (1) In gastric fundus, secretin and VIP caused a time- and temperature-dependent stimulation of cyclic AMP production that was maximal when the test agents were incubated for 60 min at 20 degrees C in the presence of 0.5 mM 3-isobutyl-1-methylxanthine as a phosphodiesterase inhibitor. The dose-response curve was monophasic for both peptides, the production of cyclic AMP being sensitive to 10(-10) M secretin and to 5 . 10(-8) M VIP. Half-maximal stimulation was obtained with 2.9 10(-9) M secretin or 2 . 10(-7) M VIP and the maximal stimulation represented a 21-fold and a 19-fold increase above control for secretin and VIP, respectively. Histamine also stimulated cyclic AMP production, with a Km of about 5 . 10(-4) M. No additive effect on cyclic AMP production was oberved when secretin and VIP were simultaneously added at maximally active concentrations, while an additive effect was observed when secretin and histamine were added together. (2) In gastric antrum, the characteristics of the secretin- and VIP-stimulated cyclic AMP production were similar to those observed in gastric fundus. Histamine nevertheless failed to stimulate the formation of cyclic AMP in antral mucosa. (3) These data demonstrate the existence of a cyclic AMP system highly sensitive to secretin in gastric glands isolated from the rat fundus and antrum and suggest that VIP operates through this system. (4) It is proposed that the pepsinogen- and/or mucous-secreting cells are implicated in the regulation of cyclic AMP production by secretin in gastric glands of the rat.

Animals↗
PubMed1979

[Vasoactive intestinal peptide (VIP): specific receptors and adenylate cyclase activation in a human prolactin-secreting pituitary tumor].

Receptors for the Vasoactive Intestinal Peptide (VIP) were characterized in particles enriched in plasma membranes obtained from a human prolactin-secreting pituiatry tumor. Native VIP inhibited competitively the binding of 125I-VIP to the particles and stimulated cyclic AMP production; both these effects were observed at concentrations of VIP as low as 10(-11)-10(-10) M, which are compatible with VIP concentrations in the hypothalamopituitary portal blood.

Adenylyl Cyclases↗
PubMed1979

Ontogeny and distribution of immunoreactive gastric inhibitory polypeptide (IR-GIP) in rat small intestine.

The ontogeny and distribution of immunoreactive gastric inhibitory polypeptide (IR-GIP) has been studied in the rat duodenum and jejunoileum between day 20 post-coitum and day 150 post-partum by radioimmunoassay following tissue extraction. In foetuses on day 20 of gestation, the content of IR-GIP was 2.0 +/- 0.2 ng/duodenum and 18 +/- 2.0 ng/jejuno-ileum. The IR-GIP content increased during the whole period investigated and a peak of concentration was observed in the first post-natal week in both the duodenum (860 +/- 150 ng/g) and jejunoileum (650 +/- 135 ng/g). In the duodenum, the main increase in IR-GIP content (ng per organ) occurred in the 3rd week of life and the same phenomenon was observed 2 weeks later in the jejuno-ileum. The highest GIP concentration was found in the duodenum and in the proximal jejunum, indicating that the upper small intestine is the major site of IR-GIP storage. It is concluded that the ontogeny of IR-GIP further supports the concept that this hormone is involved in the endocrine regulation of metabolism and suggests that this regulatory process takes place at an early stage of rat development.

Age Factors↗
PubMed1978

[Evidence of an ileal hormone inhibiting pancreatic secretion (ACP anticholecystokinine peptide)].

The contact of long and medium chain fatty acids with the ileal mucosa inhibits basal or stimulated pancreatic protein secretion of Man, Dog, Cat and Rat. This inhibition is due to an inhibitory factor transmitted by cross-circulation. We isolated from partially purified extracts of Pig ileum a peptide which inhibits strongly volume and protein pancreatic output of the conscious Rat. We propose to call this factor ACP, anticholecystokinine peptide.

Animals↗
PubMed1977

[Secretion of insulin and of glucagon by the perfused pancreas of newborn rats: effect of vasoactive intestinal peptide Vip].

A method is described for perifusion of the splenic part of the pancreas from 48-64 hour-old rat. In different basal conditions, the secretion of insulin and glucagon is stable and reproducible for 90 mn. The addition of the vasoactive intestinal peptide (VIP) to these perifusion media, at a concentration as low as 2 ng/ml, determines a remarkable increase of insulin and of glucagon secretion. These results suggest the possibility of a VIP action in the physiology of endocrine pancreas.

Amino Acids↗
PubMed1977

Vasoactive intestinal peptide (VIP): variation of the jejuno-ileal content in the developing rat as measured by radioreceptorassay.

This study was undertaken to investigate the variations of the Vasoactive Intestinal Peptide (VIP) content of rat jejuno-ileum (JI) with age. VIP was measured by its ability to inhibit competitively the binding of [125I]pork VIP (pVIP) to rat liver plasma membranes. The radio receptor assay was sensitive to 0.5 ng/ml. VIP fragments 1-6, 14-28 and 18-28 exhibited no cross reaction with [125I]pVIP. Glucagon had no effect and secretin was about 100 times less effective than pVIP. Rat VIP was extracted from JI by 0.5 M acetic acid and partially purified by adsorption on silicate. The effect of JI extracts in inhibiting the binding of [125I]pVIP paralleled that of pVIP used as standard. The VIP content of JI showed a 340-fold increase between day 21 post coitum (p.c.): 41 +/- 4 ng/JI and day 63 post partum (p. p.): 14 110 +/- 954 ng/JI. On a gut weight basis, VIP increased slightly from day 21 p. c. (591 +/- 51 ng/g of JI) to day 14 p. p. (906 +/- 109 ng/g of JI) and then increased more sharply (day 21 p. p.: 1508 +/- 222 ng/g of JI) until day 63 p. p. (2672 +/- 207 ng/g of JI). The VIP content seemed to reach a plateau after 2 months. A similar pattern was observed when the results were expressed per mg of JI protein. It is speculated that the rise in VIP content is related to the role of this peptide in the regulation of the gastro-intestinal function and/or the distribution of fuels in the organism.

Age Factors↗
PubMed1976

Interactions of glucagon and related peptides with chicken adipose tissue.

The effect of glucagon, Vasoactive Intestinal Polypeptide (VIP), secretin and gut glucagon on the cyclic adenosine 3'5' monophosphate (cAMP) level, and on the specific binding of these 125I-peptides to the adipocyte plasma membrane was measured in chicken adipocytes and compared to the results obtained in rat adipocytes. The displacement of 125I-glucagon from its specific sites was observed with about the same concentration of unlabeled hormone in fat cell plasma membranes of both species. However, the rise in cAMP induced by glucagon was much higher in chicken than in rat adipocytes. In chicken fat cells unlike rat fat cells, the cAMP accumulation elicited by glucagon was maintained during at least 60 min even in the absence of theophylline. Theophylline at 1-10 mM potentiated the glucagon-stimulated cAMP levels in rat fat cells, but had only a slight effect, if any, in chicken adiposyces. Porcine VIP, secretin or gut glucagon exerted no detectable action on the cAMP level of chicken adipocytes. The lack of cAMP accumulation was in good agreement with the absence of binding of 125I-VIP and 125I-secretin by chicken plasma membranes. These findings suggest that: 1) the difference of glucagon effect in rat and chicken fat cells results from variations in the rate of degradation of cAMP rather than from differences in the specific binding of glucagon between the two species; 2) the use of chicken fat cells is suitable to discriminate between glucagon and structurally related peptides from mammals.

Adipose Tissue↗