• Asian-Australasian Journal of Animal Sciences
• /
• 제20권1호
• /
• pp.60-69
• /
• 2007

Ruminants eating dry forage secrete large volumes of saliva which results in decreased plasma volume (hypovolemia) and the loss of $NaHCO_3$ from the blood. The present research investigated whether or not hypovolemia and the loss of $NaHCO_3$ from the blood in goats brought about by dry forage feeding actually depresses feed intake and saliva secretion, respectively. The present experiment consisted of three treatments (NI, ASI, MI). In the control treatment (NI), a solution was not infused. In the ASI treatment, i.v. infusion of artificial parotid saliva was initiated 1 h before feeding and continued for the entire 2 h feeding period. In the MI treatment, iso-osmotic mannitol solution was infused. The NI treatment showed that hematocrit and plasma total protein concentration were increased due to decreased circulating plasma volume brought about by feeding. In the ASI treatment, the fluid and $NaHCO_3$ that were lost from the blood because of a feeding-induced acceleration of saliva secretion was replenished with an intravenous infusion of artificial parotid saliva. This replenishment lessened the levels of suppression on both feeding and parotid saliva secretion. When only the lost fluid was replenished with an intravenous infusion of iso-osmotic mannitol solution in the MI treatment, the degree of feeding suppression was lessened but the level of saliva secretion suppression was not affected. These results indicate that the marked suppression of feed intake during the initial stages of dry forage feeding was caused by a feeding-induced hypovolemia while the suppression of saliva secretion was brought about by the loss of $NaHCO_3$ from the blood due to increased saliva secretion during the initial stages of feeding.

• 대한약리학회지
• /
• 제17권1호
• /
• pp.27-32
• /
• 1981

It has been known that ethanol stimulates the secretion of gastric acid regardless of its route of administration. Recently, however, some studies have challenged this view and claimed that ethanol inhibits the gastric acid secretion. This study was undertaken to investigate the effects of ethanol on the gastric acid secretion in anesthetized rat in respect to the route of administration and the concentration of alcohol. Normal saline (pH adjusted to 6.0) was used as standard perfusion solution and ethanol was mixed as 0.8, 1.7, 5, 10 and 20%. Four ml of perfusion fluid was given into stomach via gastric tube and drained from duodenal tube every 5 min. Acid secretion was measured by back titration to pH 6.0 with N/20 NaOH and expressed as ${\mu}Eq/5$ min. Low concentration of ethanol up to 1.7% in perfusion solution caused little changes in acid secretion, but moderate concentration such as perfusion of 5% or 10% ethanol solution inhibited both the basal and histamine-induced gastric secretion. Moreover, loss of perfused acid was seen by 20% ethanol, which means back diffusion of hydrogen ions into the gastric mucosa. However, intravenous administration of ethanol, maintained at the level of 0.1% alcohol in blood, caused significant stimulation of gastric acid. We, therefore, conclude that in anesthetized rat ethanol has dual effects on acid secretion, i.e., inhibiting and enhancing by oral and intravenous administration, respectively, but further investigation is necessary to clarify these effects.

• Biomolecules & Therapeutics
• /
• 제3권1호
• /
• pp.72-79
• /
• 1995

The antiulcer effects of newly synthesized prostaglandin derivatives were investigated in various experimental ulcer models and on gastric secretion in rats. HK-3 and HK-4, PG $E_2$derivatives, prevented the formation of acute gastric ulcer induced by ethanol or aspirin in pylorus-ligated rats. The ulcer formation was moderately inhibited by HK-1 and HK-2, PG $F_{2{\alpha}}$ derivatives, and aggravated by SK-1, SK-2 and SK-3, PG $F_{2{\alpha}}$ derivatives. HK-3 and HK-4 reduced the volume, acid output and pepsin output of gastric juice in pylorus-ligated rats. The gastric perfusion with physiologic saline(pH 6.0) showed relatively constant acid secretion and indomethacin increased the acid secretion. The acid secretion was markedly decreased by PG $E_2$but PG $F_{2{\alpha}}$ caused little change. Prostaglandin derivatives, especially HK-3 arid HK-4, significantly inhibited the acid secretion induced by indomethacin. The results show that, PG $E_2$ derivatives, HK-3 and HK-4, inhibit acid secretion and also have protective effects on gastric ulceration induced by ethanol or aspirin.

• BMB Reports
• /
• 제30권6호
• /
• pp.379-384
• /
• 1997

The effects of several ions on the specific activity and isozyme patterns of cellular and secretory isoperoxidases were studied in suspension-cultured cells of rice (Oryza sativa L.). Peroxidase release into the culture medium occurred in the absence of added calcium. The addition of calcium ion greatly stimulated the secretion of cationic isoperoxidases such as C2 and C3 into the medium: a maximum 11 fold increase of secretions occurred in the presence of 5 mM $CaCl_2$, and the secretion was accomplished within 1 hour after the addition of $CaCl_2$. About a 10 fold increase of the peroxidase secretion into the medium did occur with 0. 5% NaCl, whereas cellular isoperoxidase levels were reduced notably. About a 6 fold increase of the specific activity of cellular isoperoxidase was found in 5 mM $NiCl_2$-treated cell, while $NiCl_2$ had no effect on the secretion of peroxidase into the medium. Various concentrations of KCl did not change peroxidase secretion, but 5 mM $ZnCl_2$ reduced peroxidase secretion greatly. The major secretory isoperoxidases stimulated by $CaCl_2$, NaCl and cellulase were composed of cationic isoperoxidases C2 and C3, which were found to be localized in the cell wall of rice by examination of the enzyme in the protoplast. Furthermore, the secretion rates of secretory isoperoxidases were increased rapidly when cellulase was treated in the absence of the osmotic stabilizer of 0.4 M mannitol. These results suggest that the stimulations of secretory isoperoxidase levels seem to be due to the stimulation of secretion into the culture medium of rice.

• 대한약리학회지
• /
• 제13권2호
• /
• pp.41-48
• /
• 1977

In 1968, Case et al. first studied the importance of cyclic AMP as an intermediate in the action of secretin and cholecystokinin-pancreozymin and they suggested that the action of secretin, not that of cholecystokinin-pancreozymin, may be mediated through cyclic AMP. Recently Albano et al. reported that in the exocrine pancreas each of the two major physiological functions is modulated a specific cyclic nucleotide, enzyme secretion by cyclic GMP, and fluid and ionic secretion by cyclic AMP. But in pancreas still conflicting results have been reported on the role of cyclic nucleotides in enzyme and electrolyte secretion. In these study, the role of cyclic nucleotides in the exocrine pancreatic secretion was examined. The results are as follows. 1) Very strong stimulation on amylase release from guinea pig pancreatic slice was produced by 1 unit of cholecystokinin-pancreozymin but as compared to that of cholecystokinin-pancreozymin very weak response was observed by 1 unit of secretion or $1\;{\mu}g$ of VIP. 2) Both cholecystokinin-pancreozymin and acetylcholine produced a rapid and marked rise in cyclic GMP as well as cyclic AMP in isolated pancreatic tissue. However, both secretin and VIP failed to alter significantly the basal level of cyclic GMP in pancreatic fragments. 3) Atropine inhibited acetylcholine mediated amylase release, but did not affect the cholecystokinin-pancreozymin response. Furthermore, atropine pretreatment produced a marked inhibitory effect on the increase of tissue cyclic nucleotides induced by cholecystokinin-pancreozymin and acetylcholine. In summary, these results suggest that whereas the pancreatic secretion produced by secretin and VIP is modulated by the formation of cyclic AMP, the pancreatic enzyme secretion in response to cholecystokinin-pancreozymin and acetylcholine is triggered by both cyclic AMP and cyclic GMP.

• Archives of Pharmacal Research
• /
• 제14권1호
• /
• pp.55-67
• /
• 1991

The influence of caffeine on secretion of catecholamines (CA) was examined in the isolated perfused rat adrenal gland. Caffeine (0.3 mM) perfused into an adrenal vein of the gland produced a marked increase in secretion of CA. This secretory effect of CA evoked by perfusion of caffeine for one minute was considerably prolonged, lasting for more than 90 minutes. The tachyphylaxis to releasing effect of CA induced by caffeine was observed by repeated perfusion of this drug. The caffeine-evoked CA secretion was markedly inhibited by pretreatment with ouabain, trifluoperazine, TMB-8 and perfusion with calcium-free Krebs solution containing 5 mM EGTA, but was not affected by perfusion of calcium-free Krebs solution without other addition. CA secretion evoked by caffeine was not reduced significantly by pretreatment with chlorisondamine but after the first collection of perfusate for 3 min was clearly inhibited. Interestingly, the caffeine-evoked CA secretion was considerably potentiated by pretreatment with atropine or pirenzepine, but after the first collection for 3 min it was markedly decreased. These experimental results suggest that caffeine causes a marked increase in secretion of CA from the isolated perfused rat adrenal gland by an extracellular calcium-independent exocytotic mechanism. The secretory effect of caffeine may be mainly due to mobilization of calcium from an intracellular calcium pool in the rat chromaffin cells and partly due to stimulation of both muscarinic and nicotinic receptors.

• The Korean Journal of Physiology
• /
• 제25권1호
• /
• pp.27-35
• /
• 1991

Generally, it has been known that cholecystokinin (CCK) release into the plasma is under cholinergic control, but secretin release is not. Thus in anesthetized dogs we studied the effect of atropine $(50\;{\mu}g/kg\;followed\;by\;50\;{\mu}g/kg/hr)$ on pancreatic secretion and plasma concentrations of bioactive CCK and immunoreactive secretin in response to intraduodenal perfusion of sodium oleate (1, 3 and 9 mmol/hr). The volume, protein output and bicarbonate output of the secretion were increased by sodium cleats and this oleate-induced secretion was decreased significantly by atropine administration. However the increased plasma CCK and secretin levels by sodium oleate were not changed by atropine. These results indicate that atropine suppressed sodium oleate-induced pancreatic secretion through inhibiting cholinergic mechanism directly rather than decreasing the release of pancreatic secretory hormones. In another set of experiments, bilateral cervical vagi were stimulated electrically to observe the changes of pancreatic secretion and the above two plasma hormone levels in the presence or absence of atropine. In the vagally stimulated dogs, the volume, protein output and bicarbonate output of the pancreatic secretion were increased significantly. Both plasma secretin and CCK were concomitantly released significantly by vagal stimulation. Atropine significantly depressed the pancreatic secretory response as well as the release of these two pancreatic secretory hormones. Therefore, we conclude that in the presence of atropine the depressed pancreatic response to vagal stimulation is at least, in part, due to decreased release of endogenous CCK and secretin. In the vagally stimulated animals, however, the involvement of direct cholinergic influence on pancreatic exocrine gland remains to be answered.

• Journal of Microbiology and Biotechnology
• /
• 제21권7호
• /
• pp.679-685
• /
• 2011

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

• The Korean Journal of Physiology and Pharmacology
• /
• 제10권6호
• /
• pp.317-321
• /
• 2006

In this study, we investigated whether glycyrrhizin, prunetin and morroniside affect mucin secretion from cultured airway epithelial cells and compared the possible activities of these agents with the inhibitory action on mucin secretion by poly-L-lysine (PLL) and the stimulatory action by adenosine triphosphate (ATP). Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled using $^{3}H-glucosamine$ for 24 h and chased for 30 min in the presence of varying concentrations of each agent to assess the effects on $^{3}H-mucin$ secretion. The results were as follows: 1) glycyrrhizin and morroniside increased basal mucin secretion from airway; 2) prunetin did not affect basal mucin secretion; 3) glycyrrhizin did not inhibit ATP-induced mucin secretion. We conclude that glycyrrhizin and morroniside can increase basal mucin secretion, by directly acting on airway mucin-secreting cells and suggest that two compounds be further investigated for the possible use as mild expectorants during the treatment of inflammatory airway diseases.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제8권2호
• /
• pp.162-165
• /
• 2003

In order to study the secretion of the human urokinase-type plasminogen activator, u-PA, from the yeast yarrowia lipolytica, three kinds of integrative expression vector were constructed. These vectors differed only in their secretion control legions, pre-, pre-dip-(dipeptide Stretch) or pre-dip-pro sequences of the alkaline extracellular protease, which were joined inflame to the human u-PA cDNA. The recombinant Y. lipolytica Strains, transformed with the expression vectors, secreted the hyperglycosylated u-PA. A fibrin plate assay of the culture supernatants showed that the hyperglycosylated u-PA proteins could catalyze fibrinolysis, and that the pre-dip sequence was the most efficient secretory signal for the secretion of the u-PA from Y. lipolyica. This result suggests that Y. lipolytica can be developed as a potential host for the production of recombinant human u-PA.