scholarly journals Ketogenesis from butyrate and acetate by the caecum and the colon of rabbits

1972 ◽  
Vol 130 (3) ◽  
pp. 785-790 ◽  
Author(s):  
S. J. Henning ◽  
F. J. R. Hird
Keyword(s):  
Carbon Dioxide ◽  
Liver Tissue ◽  
Ketone Bodies ◽  
Distal Colon ◽  
Proximal Colon ◽  
Enzyme Assays ◽  
Liver Slices

1. When studied in vitro, tissue from the caecum and the proximal colon of rabbits converted butyrate into ketone bodies. The conversion was similar to that observed with liver slices. The ketogenic activity was associated with the mucosa rather than the muscle of the gut wall and, in the colon, diminished as the distance from the caecal–colonic junction increased. 2. Tissue from the wall of the ileum, caecum, proximal colon and distal colon was also shown to metabolize [1-14C]butyrate to carbon dioxide. 3. Enzyme assays showed that in both liver tissue and caecal mucosa the activity of hydroxymethylglutaryl-CoA synthase was more than ten times that of acetoacetyl-CoA deacylase. Labelling experiments in vitro gave confirmation of the hydroxymethylglutaryl-CoA pathway. 4. The significance of the conversion of butyrate into ketone bodies is discussed.

Postnatal development of colonic electrolyte transport in rabbits

1990 ◽  
Vol 258 (3) ◽  
pp. G447-G453 ◽  
Author(s):  
E. V. O'Loughlin ◽  
D. M. Hunt ◽  
D. Kreutzmann
Keyword(s):  
Chloride Transport ◽  
Age Groups ◽  
Serum Cortisol ◽  
Distal Colon ◽  
Proximal Colon ◽  
Transport Studies ◽  
Age Related ◽  
Serum Aldosterone ◽  
Group Transport

Postnatal changes in adrenal gluco- and mineralocorticoid secretion and colonic sodium and chloride transport were examined. New Zealand White rabbits, age 10-14, 18-22, and 25-30 days, and adult animals (6-10 wk) were studied. Serum cortisol, corticosterone, aldosterone, and mucosal Na(+)-K(+)-ATPase activities were measured in each age group. Transport studies were performed in vitro under short-circuited conditions in distal colon at all age groups and in proximal colon in days 10-14 and 18-22 and in adult animals. Serum glucocorticoids varied little until after day 30 when they rose to adult levels. On the other hand, serum aldosterone levels were two- to threefold higher in days 10-14 and 18-22 animals but fell to adult levels by day 25. In distal colon, amiloride-inhibitable electrogenic Na+ absorption was present at all ages but was significantly greater (P less than 0.01) in days 10-14 (3.8 +/- 0.5 mu eq.cm-2.h-1) and 18-22 (4.2 +/- 0.4) rabbits compared with adults (1.9 +/- 0.4) but not day 25-30 (2.8 +/- 0.5). In proximal colon, Na+ absorption was significantly higher (P less than 0.05) in day 10-14 (1.6 +/- 0.5 mu eq.cm-2.h-1) compared with day 18-22 (-0.2 +/- 0.5) and adults (0.06 +/- 0.5) and was amiloride insensitive. Neither chloride transport nor mucosal Na(+)-K(+)-ATPase demonstrated significant age-related changes in either region of colon. These results indicate that both proximal and distal colonic Na+ transport undergoes postnatal changes. In distal but not proximal colon these changes appear to be regulated by circulating aldosterone probably by increasing apical membrane permeability to Na+.

Liver slices in in vitro pharmacotoxicology with special reference to the use of human liver tissue

1997 ◽  
Vol 12 (1) ◽  
pp. 77-100 ◽  
Author(s):  
P. Olinga ◽  
D.K.F. Meijer ◽  
M.J.H. Slooff ◽  
G.M.M. Groothuis
Keyword(s):  
Special Reference ◽  
Liver Tissue ◽  
Human Liver ◽  
Human Liver Tissue ◽  
Liver Slices

THE UTILIZATION OF ACETATE BY LIVER AND ADIPOSE TISSUE OF GROWTH HORMONE TREATED RATS OF DIFFERENT AGES

1957 ◽  
Vol 35 (1) ◽  
pp. 759-766 ◽  
Author(s):  
W. F. Perry ◽  
Helen F. Bowen
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Growth Hormone ◽  
Adipose Tissue ◽  
Young Adult ◽  
Age Groups ◽  
Fat Content ◽  
Liver Slices ◽  
Old Rats

The effect of growth hormone on the in vitro incorporation of C14 acetate into fatty acids, carbon dioxide, and cholesterol by liver and adipose tissue from young, adult, and old rats was studied.In all three age groups of animals, growth hormone was found to depress the incorporation of acetate into fatty acids by liver slices but the CO2 production was unaffected. In both young and old animals growth hormone did not significantly alter the incorporation of acetate into fatty acids and CO2 by preparations of adipose tissue, but did result in a decline in the fat content of the adipose tissue. It was noted that the CO2 production from acetate was much less with adipose tissue from old rats than with similar preparations from young rats.Incorporation of acetate into cholesterol was unaffected by growth hormone in young and old animals but was significantly increased in liver slices from adult animals.

scholarly journals Formation of ketone bodies from [14C]palmitate and [14C]glycerol by tissues from ketotic sheep

1968 ◽  
Vol 106 (1) ◽  
pp. 289-292 ◽  
Author(s):  
J. A. Taylor ◽  
H. D. Jackson
Keyword(s):  
Carbon Dioxide ◽  
Ketone Bodies ◽  
Epithelial Tissue ◽  
Complete Oxidation ◽  
Long Chain Fatty Acids ◽  
Rumen Epithelium ◽  
Extrahepatic Tissues ◽  
Sheep Rumen ◽  
Tissue Nitrogen

Labelled ketone bodies were produced readily from [U−14C]palmitate, [2−14C]palmitate and [1−14C]glycerol by sheep rumen-epithelial and liver tissues in vitro. On a tissue-nitrogen basis, both tissues had similar capacities for ketogenesis. Palmitate was a ketogenic substrate in both rumen-epithelial tissue and liver, and more of its 14C appeared in ketone bodies than in the 14CO2 liberated. Glycerol was actively metabolized to ketone bodies, but more readily underwent complete oxidation to carbon dioxide; this complete oxidation was most pronounced in rumen-epithelial tissue from ketotic ewes. These experiments with labelled compounds confirm earlier observations that rumen-epithelial tissue, like liver, actively forms ketone bodies from long-chain fatty acids and show further that normal rumen-epithelial tissue can convert palmitate into ketone bodies as readily as into carbon dioxide. Free glycerol, which is metabolized only by liver tissue in non-ruminants, is also metabolized by rumen epithelium. The rumen epithelium thus has unique metabolic capacity among extrahepatic tissues.

Different types of contractions in rat colon and their modulation by oxidative stress

2001 ◽  
Vol 280 (4) ◽  
pp. G546-G554 ◽  
Author(s):  
Asensio Gonzalez ◽  
Sushil K. Sarna
Keyword(s):  
Potential Role ◽  
Contractile Response ◽  
Circular Muscle ◽  
Distal Colon ◽  
Proximal Colon ◽  
Rat Colon ◽  
Hla B27 ◽  
Different Types

The aim of this study was to investigate the modulation of in vitro rat colonic circular muscle contractions by dextran sodium sulfate (DSS)-induced inflammation and in spontaneous inflammation in HLA-B27 rats. We also examined the potential role of hydrogen peroxide (H2O2) in modulating excitation-contraction coupling. The muscle strips from the middle colon generated spontaneous phasic contractions and giant contractions (GCs), the proximal colon strips generated primarily phasic contractions, and the distal colon strips were mostly quiescent. The spontaneous phasic contractions and GCs were not affected by inflammation, but the response to ACh was suppressed in DSS-treated rats and in HLA-B27 rats. H2O2production was increased in the muscularis of the inflamed colon. Incubation of colonic muscle strips with H2O2suppressed the spontaneous phasic contractions and concentration and time dependently reduced the response to ACh; in the middle colon, it also increased the frequency of GCs. We conclude that H2O2mimics the suppression of the contractile response to ACh in inflammation. H2O2also selectively suppresses phasic contractions and increases the frequency of GCs, as found previously in inflamed dog and human colons.

THE UTILIZATION OF ACETATE BY LIVER AND ADIPOSE TISSUE OF GROWTH HORMONE TREATED RATS OF DIFFERENT AGES

1957 ◽  
Vol 35 (9) ◽  
pp. 759-766 ◽  
Author(s):  
W. F. Perry ◽  
Helen F. Bowen
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Growth Hormone ◽  
Adipose Tissue ◽  
Young Adult ◽  
Age Groups ◽  
Fat Content ◽  
Liver Slices ◽  
Old Rats

The effect of growth hormone on the in vitro incorporation of C14 acetate into fatty acids, carbon dioxide, and cholesterol by liver and adipose tissue from young, adult, and old rats was studied.In all three age groups of animals, growth hormone was found to depress the incorporation of acetate into fatty acids by liver slices but the CO2 production was unaffected. In both young and old animals growth hormone did not significantly alter the incorporation of acetate into fatty acids and CO2 by preparations of adipose tissue, but did result in a decline in the fat content of the adipose tissue. It was noted that the CO2 production from acetate was much less with adipose tissue from old rats than with similar preparations from young rats.Incorporation of acetate into cholesterol was unaffected by growth hormone in young and old animals but was significantly increased in liver slices from adult animals.

scholarly journals Deoxycholic acid activates colonic afferent nerves via 5-HT3 receptor-dependent and -independent mechanisms

2019 ◽  
Vol 317 (3) ◽  
pp. G275-G284 ◽  
Author(s):  
Yang Yu ◽  
Egina C. Villalobos-Hernandez ◽  
Sabindra Pradhananga ◽  
Corey C. Baker ◽  
Christopher Keating ◽  
...  
Keyword(s):  
Bile Acids ◽  
Deoxycholic Acid ◽  
Neuronal Cell ◽  
Distal Colon ◽  
Proximal Colon ◽  
High Threshold ◽  
Secondary Bile Acid ◽  
Afferent Nerves ◽  
Spinal Afferents

Increased bile acids in the colon can evoke increased epithelial secretion resulting in diarrhea, but little is known about whether colonic bile acids contribute to abdominal pain. This study aimed to investigate the mechanisms underlying activation of colonic extrinsic afferent nerves and their neuronal cell bodies by a major secondary bile acid, deoxycholic acid (DCA). All experiments were performed on male C57BL/6 mice. Afferent sensitivity was evaluated using in vitro extracellular recordings from mesenteric nerves in the proximal colon (innervated by vagal and spinal afferents) and distal colon (spinal afferents only). Neuronal excitability of cultured dorsal root ganglion (DRG) and nodose ganglion (NG) neurons was examined with perforated patch clamp. Colonic 5-HT release was assessed using ELISA, and 5-HT immunoreactive enterochromaffin (EC) cells were quantified. Intraluminal DCA increased afferent nerve firing rate concentration dependently in both proximal and distal colon. This DCA-elicited increase was significantly inhibited by a 5-HT3 antagonist in the proximal colon but not in the distal colon, which may be in part due to lower 5-HT immunoreactive EC cell density and lower 5-HT levels in the distal colon following DCA stimulation. DCA increased the excitability of DRG neurons, whereas it decreased the excitability of NG neurons. DCA potentiated mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. Together, this study suggests that DCA can excite colonic afferents via direct and indirect mechanisms but the predominant mechanism may differ between vagal and spinal afferents. Furthermore, DCA increased mechanosensitivity of high-threshold spinal afferents and may be a mechanism of visceral hypersensitivity. NEW & NOTEWORTHY Deoxycholic acid (DCA) directly excites spinal afferents and, to a lesser extent, indirectly via mucosal 5-HT release. DCA potentiates mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. DCA increases vagal afferent firing in proximal colon via 5-HT release but directly inhibits the excitability of their cell bodies.

Steroids alter ion transport and absorptive capacity in proximal and distal colon

1985 ◽  
Vol 249 (1) ◽  
pp. G113-G119 ◽  
Author(s):  
J. H. Sellin ◽  
R. C. DeSoignie
Keyword(s):  
Ion Transport ◽  
Absorptive Capacity ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Proximal Colon ◽  
High Rate ◽  
Transport Parameters ◽  
In Vitro Effects

Steroids are potent absorbagogues, increasing Na and fluid absorption in a variety of epithelia. This study characterizes the in vitro effects of pharmacological doses of gluco- and mineralocorticoids on transport parameters of rabbit proximal and distal colon. Treatment with methylprednisolone (MP, 40 mg im for 2 days) and desoxycortone acetate (DOCA, 12.5 mg im for 3 days) resulted in a significant increase in short-circuit current (Isc) in distal colon, suggesting an increase in basal Na absorption. Amiloride (10(-4) M) caused a significantly negative Isc in MP-treated tissue, demonstrating a steroid-induced, amiloride-insensitive electrogenic ion transport in distal colon. The effect of two absorbagogues, impermeant anions (SO4-Ringer) and amphotericin, were compared in control and steroid-treated distal colon. In controls, both absorbagogues increased Isc. Impermeant anions caused a rise in Isc in both MP and DOCA tissues, suggesting that the high rate of basal Na absorption had not caused a saturation of the Na pump. The steroid-treated colons, however, did not consistently respond to amphotericin. Amiloride inhibited the entire Isc in MP-treated distal colon that had been exposed to amphotericin; this suggested that amphotericin had not exerted its characteristic effect on the apical membrane of steroid-treated colon. In proximal colon, steroids did not alter basal rates of transport; however, epinephrine-induced Na-Cl absorption was significantly greater in MP-treated vs control (P less than 0.005). Steroids increase the absorptive capacity of both proximal and distal colon for Na, while increasing basal Na absorption only in the distal colon.(ABSTRACT TRUNCATED AT 250 WORDS)

THE IN VITRO UTILIZATION AND PRODUCTION OF NON-ESTERIFIED FATTY ACIDS BY ADRENALECTOMIZED RATS

1961 ◽  
Vol 39 (6) ◽  
pp. 1061-1065 ◽  
Author(s):  
W. F. Perry ◽  
Helen F. Bowen
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Liver Tissue ◽  
In Vitro Production ◽  
Esterified Fatty Acids ◽  
Adrenalectomized Animal ◽  
Vitro Production ◽  
Adrenalectomized Rats

The in vitro utilization of non-esterified fatty acids by various tissues and the in vitro production of non-esterified fatty acids by adipose tissue have been compared in normal and adrenalectomized rats. It was found that the production of NEFA by adipose tissue was similar in both groups of animals but that the in vitro utilization of NEFA and production of carbon dioxide by heart, diaphragm, kidney, and liver tissue was greater in the adrenalectomized animal. These findings together with the depletion of fat content of the depots are interpreted as indicating that in the adrenalectomized state there is increased peripheral utilization of fatty acids.

Dietary flavonol quercetin induces chloride secretion in rat colon

1998 ◽  
Vol 275 (5) ◽  
pp. G1166-G1172 ◽  
Author(s):  
Rainer Cermak ◽  
Ursula Föllmer ◽  
Siegfried Wolffram
Keyword(s):  
Short Circuit ◽  
Ussing Chamber ◽  
Phosphodiesterase Inhibitor ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Proximal Colon ◽  
Rat Colon ◽  
Quercetin Glycoside

The aim of this study was to investigate the possible effects of the flavonol quercetin, the most abundant dietary flavonoid, on the intestinal mucosa. In vitro experiments were performed with various segments of the rat intestine, using the Ussing chamber technique. Quercetin increased the short-circuit current ( I sc) in the jejunum, ileum, and proximal and distal colon. Additional experiments were performed using preparations of the proximal colon. The maximum effective dose of quercetin was found to be ∼100 μM. The quercetin-induced increase in I sc was inhibited by the Cl− channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid. Adding blockers of the Na+-K+-2Cl−cotransporter to the serosal compartment diminished the increase of I sc due to quercetin. Ion substitution and flux measurements indicated that the effect of quercetin was due to electrogenic Cl− and[Formula: see text] secretion. In contrast to the aglycone, the quercetin glycoside rutin had no effect. The effect of quercetin on I scwas additive to the I sc increase induced by forskolin, but the flavonoid diminished the I sc evoked by carbachol. The phosphodiesterase inhibitor theophylline blocked the effect of quercetin. Genistein, a related isoflavone, did not alter the I sc evoked by quercetin. These findings demonstrate that the dietary flavonol quercetin induces Cl−secretion and most likely [Formula: see text]secretion in rat small and large intestine. The effects are restricted to the flavonol aglycone.

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