Biomedical subjects

V Sorribas

Publications and source records attributed to V Sorribas.

27 records · Page 2Linked to original sources

PubMed1993

Action of robenidine on the intestinal transport and digestion of nutrients in rabbit.

Robenidine is an anticoccidial guanidine used as an additive in rabbit fodder. Because its action is restricted to the small intestine, the present work addresses the question whether robenidine affects the growth of the animals, sugar and amino acid intestinal transport and membrane-bound intestinal digestion. For this purpose we have determined the intestinal transport of the substrates, and the enzymatic activity of neutral aminopeptidase and sucrase. We have found that robenidine diminishes the tissue accumulation of L-leucine and D-galactose at long incubation times, and increases the transepithelial mucosal to serosal flux of both substrates. These results suggest that robenidine may stimulate the enterocyte basolateral membrane flux of sugars and neutral amino acids. These results have been corroborated by means of isolated brush border and basolateral membrane vesicles. Apart from these effects, robenidine has also been shown to increase the enzymatic activity of neutral aminopeptidase and sucrase and thus resulting in a better digestion of nutrients.

Aminopeptidases↗

PubMed1993

Expression cloning of human and rat renal cortex Na/Pi cotransport.

We have isolated two cDNA clones, NaPi-2 and NaPi-3, by screening rat kidney cortex and human kidney cortex cDNA libraries, respectively, for expression of sodium-dependent phosphate transport in Xenopus laevis oocytes. Substrate specificity and a detailed kinetic analysis (Na, Pi, H+ concentrations) suggested that expressed uptake activities relate to proximal tubular brush border membrane Na/Pi cotransport. NaPi-2 cDNA contains 2464 bp encoding a protein of 637 aa; NaPi-3 cDNA contains 2573 bp encoding a protein of 639 aa. NaPi-2- and NaPi-3-deduced protein sequences show high homology to each other but are different from the protein sequence deduced from the previously cloned NaPi-1 cDNA (from rabbit proximal tubules). Hydropathy profile predictions suggest at least eight membrane-spanning regions in NaPi-2/3-related proteins. In vitro translation results in proteins of the expected size and suggests glycosylation. Northern blot analysis shows corresponding mRNA species (approximately 2.7 kb) in kidney cortex of various species but no hybridization with RNAs isolated from a variety of other tissues (including intestinal segments); a hybridization signal (approximately 4.8 kb) was observed only in the lung (human). We conclude that we have structurally identified two closely related proteins most likely involved in human and rat renal brush border Na/Pi cotransport.

Amino Acid Sequence↗

PubMed1993

Nicarbazin stimulates intestinal transport of L-leucine in rabbit.

Nicarbazin is an anticoccidial drug used mainly in birds, but also in rabbits. Besides the anticoccidial activity, nicarbazin has shown several other effects such as inhibition of growth and feed efficiency in poultries, and stimulation of sugar intestinal absorption in rabbits. The present work has been performed in order to check whether nicarbazin also affects L-leucine intestinal absorption. The results obtained show that nicarbazin decreases L-leucine accumulation in the jejunal tissue, and increases mucosal to serosal transepithelial fluxes of this amino acid in a dose-dependent way, without modifying its diffusion across the intestinal epithelium. The drug stimulates the amino acid uptake in brush-border and basolateral membrane vesicles, thus suggesting that nicarbazin increases the absorption of L-leucine mediated by carriers.

Animals↗

PubMed1992

Effects of nicarbazin on sugar intestinal absorption in rabbits.

Nicarbazin is an anticoccidial drug, used mainly in birds, which can also be used in rabbits. It has been shown to produce several effects, such as inhibition of growth and feed efficiency in poultry. The aim of the present work was to determine whether nicarbazin alters intestinal absorption of sugar. Results obtained show that nicarbazin decreases D-galactose accumulation in the jejunal tissue and increases mucosal to serosal transepithelial fluxes of this sugar, in both cases in a dose-dependent way. Furthermore, nicarbazin seems not to modify the sugar diffusion across the intestinal epithelium. The drug also stimulates the sugar uptake in brush border and basolateral membrane vesicles. The results suggest that in rabbits nicarbazin increases sugar intestinal absorption mediated by carriers.

Animals↗

PubMed1992

Effect of erythromycin on L-threonine transport in rabbit jejunum in vitro.

Several antibiotics characterized by different molecular structures are known to affect some intestinal activities. Some of them have been described as inhibitors of the intestinal sugar and amino acid transport with different mechanisms. Erythromycin (EM) is a macrolide antibiotic acting as a motilin agonist and thus stimulating the gastrointestinal motor activity. Since several substances which increase the motor activity of the gastrointestinal tract may produce effects on the intestinal absorption of nutrients, the present study has been carried out to determine whether erythromycin affects the L-threonine intestinal absorption. The results obtained indicate that erythromycin diminishes the L-threonine intestinal transport, probably at the mucosal border level. Two groups of experiments carried out, with Na(+)-deprived medium and ouabain-enriched medium, might indicate that erythromycin action could be due to either a direct or an indirect action on the Na(+)-dependent L-threonine transport located in the brush border.

Animals↗

PubMed1992

Effects of nicarbazin on intestinal digestion and absorption of nutrients in the rabbit.

Nicarbazin is an anticoccidial drug, used mainly in birds, which has shown several other effects including inhibition of growth and feed efficiency in poultry, and stimulation of sugar and amino acid intestinal absorption in rabbit. The present work was designed to determine whether nicarbazin added to the feed, affects growth and feed intake in rabbit, and whether the continuous ingestion of nicarbazin can alter the mechanisms of intestinal nutrient absorption or digestion in this species. Nicarbazin, administered at the recommended dose (125 ppm) had no harmful effects either on growth or on feed intake of animals. After treatment for one month with nicarbazin at the dose of 125 ppm added to the feed, rabbits displayed a higher transport ability of both D-glucose and L-leucine through the enterocyte plasma membranes than did untreated rabbits. These animals also showed higher specific activities of two brush-border enzymes, sucrase and aminopeptidase N, than the control animals.

Administration, Oral↗

PubMed1990

Effect of VIP on sugar transport in rabbit small intestine in vitro.

The vasoactive intestinal peptide (VIP) has shown to be widely distributed in the gastrointestinal mucosa, submucosa and nerves, and the existence of VIP receptors on the basolateral membrane of enterocytes has been recently reported for many species. The interaction of VIP with its receptors seemed to increase cyclic AMP level, and this nucleotide has been shown to be responsible for the intestinal secretion produced by VIP. The present study confirms that VIP inhibits the intestinal absorption of D-galactose. This effect seems to be due to the inhibition of the Na(+)-independent basolateral intestinal sugar transport system. RMI 12330A, described as adenylate cyclase inhibitors, blocked the VIP action. These findings suggest that cyclic AMP might be responsible for the inhibition of Na(+)-independent transport of D-galactose across the basolateral membrane. Moreover, results obtained to determine the possible role of calcium in the action of VIP suggest that Ca2+ play a part, directly or indirectly, in the inhibition of the D-galactose transport across the basolateral membrane produced by VIP.

Animals↗

PubMed1987

Effect of somatostatin on D-galactose transport across the small intestine of rats.

Somatostatin was found to diminish control and theophylline-treated tissue sugar accumulation as well as control and also to diminish theophylline mucosal to serosal D-galactose fluxes. When Na+ was removed from the bath solution, sugar transport was unaltered by the presence of somatostatin. The same results were obtained with phlorizin in the medium. These results seem to suggest that the action of somatostatin is restricted to the Na+-dependent sugar carrier located on the brush border of the intestinal epithelium.

Animals↗

PubMedDate not supplied

Effect of erythromycin on D-galactose absorption and sucrase activity in rabbit jejunum.

Erythromycin, an antibiotic used in the treatment of infectious diseases, produces gastrointestinal side effects such as diarrhea. The mechanisms by which erythromycin produces these effects are not known. However, erythromycin has been shown to increase gastrointestinal motor activity and to inhibit intestinal neutral amino acid absorption. Both effects could contribute to the gastrointestinal side effects observed. Because the intestinal systems of amino acid and sugar transport present similar characteristics, the aim of the present work was to determine whether erythromycin also alters D-galactose absorption and sucrase activity in rabbit jejunum. The results show that erythromycin diminishes intestinal D-galactose absorption. This effect seems to be due to an action mainly located on the Na(+)-dependent sugar transport of the mucosal border of the intestinal epithelium. Erythromycin also inhibits the Na(+)-K+ ATPase activity of the enterocyte, which might explain the inhibition of the D-galactose Na(+)-dependent transport. However, a direct action of the erythromycin molecule on the Na(+)-dependent carrier cannot be excluded. Erythromycin did not alter sucrase activity.

Animals↗