Search PubMed⌕ Search

Biomedical subjects

J Christophe

Publications and source records attributed to J Christophe.

At least 271 records · Page 15Linked to original sources
PubMed1977

Discharge of newly synthesized proteins in pure juice collected from the human pancreas. Indication of more than one pool of intracellular digestive enzymes.

The pancreatic secretion of 6 normal human volunteers was collected by endoscopic cannulation of the main pancreatic duct. The appearance of newly synthesized proteins was monitored at 1-min intervals after labeling with [75Se]methionine. The minimum transit time of these proteins from their site of synthesis to the acinar lumen was 36 +/- 8 min. Stimulation of protein secretion by a rapid intravenous injection of caerulein (40 ng per kg), 1 hr after [75Se]methionine administration, greatly decreased (by 73% on an average) the specific radioactivity of the discharged proteins. These data support the concept of a functional heterogeneity of proteins secreted by the human pancreas.

Adult↗
PubMed1976

Subcellular distribution and response to gastroinetstinal hormones of adenylate cyclase in the rat pancreas. Partial purification of a stable plasma membrane preparation.

1. The subcellular distribution of adenylate cyclase activity in rat pancreatic homogenates was examined after differential centrifugation. Divalent cations exerted significant effects on this distribution. In addition, the ratio of adenylate cyclase activities in the presence of the C-terminal octapeptide of cholecystokinin-pancreozymin and secretin was lower in the crude 'mitochondrial' fraction than in 'microsomal' fractions. This difference was due to the lability of cholecystokinin-pancreozymin receptors compared to secretin receptors. The Km,app of activation was affected more than the V by this lability. Such a degradation of cholecystokinin-pancreozymin receptors was markedly delayed by isolation and storage in the presence of a phospholipid mixture. 2. A simple, reasonably rapid (6 h), and easily reproducible method was developed to prepare a stable semi-purified plasma membrane fraction, characterized by a 10-fold increase in the specific activity of adenylate cyclase with respect to the whole homogenate. At variance with data obtained on crude subcellular fractions, the V of adenylate cyclase activity observed in this preparation, under maximal concentration of the C-terminal octapeptide of cholecystokinin-pancreozymin, was higher than that obtained with secretin or the vasoactive intestinal polypeptide.

Adenylyl Cyclases↗
PubMed1976

Influence of litter size on lipid composition in infant mice.

The amount of milk available to each member of the litter was varied by adjusting the number of mice pups to 4, 8 or 12 per dam. The total fatty acid content of the carcass of the young increased for 2 weeks, and there was more in the well-fed groups. The fatty acid contents decreased thereafter transiently in all groups until weaning. The milk diet contributed major quantities of lauric and myristic acids to peripheral tissues but not to the liver. Undernourishment during neonatal life was associated with a relative reduction in palmitoleic, oleic and linoleic acids in lipids of the carcass. In contrast the carcass of the progeny subjected to overall dietary abundance showed relative increase in palmitoleic, oleic and linoleic acids at the expense of stearic acid.

Age Factors↗
PubMed1976

In vitro action of bombesin and bombesin-like peptides on amylase secretion, calcium efflux, and adenylate cyclase activity in the rat pancreas: a comparison with other secretagogues.

Bombesin (a tetradecapeptide), the C-terminal nonapeptide of bombesin (bombesin-NP), and litorin (a parent nonapeptide), each stimulated amylase secretion from rat pancreatic fragments. These responses were not affected by atropine. The concentrations that produced half-maximal stumulation of secretion were 0.25 nM for bombesin, 0.30 nM for bombesin-NP, and 0.07 nM for litorin, as compared to 0.12 nM for caerulein and 0.80 muM for the cholinergic agent carbamylcholine. When used at maximal concentrations, bombesin, bombesin-NP, and litorin showed no action on cyclic AMP levels in the presence of 5 mM theophylline. By contrast, caerulein and secretin increased cyclic AMP levels by 27 and 208%, respectively. Bombesin, bombesin-NP, and litorin did not activate adenylate cyclase in a purified pancreatic plasma membrane preparation, whereas caerulein and secretin increased this activity 20 and 16-times, respectively...

Adenylyl Cyclases↗