Net absorption of water, chloride and hexose from the intestine of dogs

1961 ◽  
Vol 200 (1) ◽  
pp. 107-110 ◽  
Author(s):  
John H. Annegers
Keyword(s):  
Glucose Concentration ◽  
Absorption Rate ◽  
Chloride Secretion ◽  
Glucose Absorption ◽  
Curvilinear Relationship ◽  
Fluid Absorption ◽  
Chloride Absorption ◽  
Small Intestinal ◽  
Osmolar Concentration ◽  
Secretion Rates

Hexose and/or NaCl solutions were perfused at about 100 cm H2O pressure through small intestinal loops in unanesthetized dogs. The rate of glucose absorption increased in curvilinear fashion as the glucose concentration of the infusate ranged from 1% to 30% and did not differ between jejunal and ileal loops. Net chloride secretion rates were independent of perfusate hexose concentrations and were greater for jejunal than for ileal loops when nonchloride solutions were infused. Net chloride absorption rates increased with infusate concentrations ranging from 0.2% to 1.8% NaCl, and were greater for ileal than for jejunal loops. However, this difference may be due to the greater chloride secretion of jejunal loops. The curvilinear relationship between moles of glucose or chloride absorbed and lumen concentrations of these substances was rectified by plotting absorption rates against log concentration. The resulting Δ mm absorbed per hour/Δ log mm per liter concentration of the perfusate averaged 10.1 and 8.7 for chloride and glucose, respectively, in 6 dogs. Net fluid absorption rate decreased in curvilinear fashion with increasing perfusate osmolar concentration when NaCl or hexose was given. Net fluid absorption at given osmolar perfusate concentrations was greater from NaCl than from glucose or sorbose solutions.

Glucose absorption by isolated perfused rat proximal straight tubules

1990 ◽  
Vol 259 (4) ◽  
pp. F580-F586 ◽  
Author(s):  
J. L. Garvin
Keyword(s):  
Glucose Concentration ◽  
Maximum Rate ◽  
Glucose Absorption ◽  
Fluid Absorption ◽  
Flow Rates ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Rate Of Absorption ◽  
The Mean ◽  
Limiting Value

Glucose absorption was investigated in isolated perfused proximal straight tubules from rats by use of a newly developed ultramicrofluorometric assay. This assay takes advantage of the increase in fluorescence associated with the reduction of NAD to NADH while glucose is degraded to 6-phosphogluconate. When tubules were perfused at 6.70 +/- 0.42 nl.mm-1.min-1, the mean rate of glucose absorption was 11.0 +/- 1.0 pmol.mm-1.min-1, and the mean rate of fluid absorption was 0.61 +/- 0.06 nl.mm-1.min-1. Glucose transport is generally due to Na-glucose cotransport in the proximal nephron. In the rat proximal straight tubule, glucose absorption also appeared to be primarily due to Na-glucose cotransport, since 10(-4) M phlorizin inhibited absorption by 100%, as did inhibition of Na(+)-K(+)-ATPase by K removal. To determine the maximum rate of transport, tubules were perfused at rates greater than 20 nl.mm-1.min-1 with a solution containing 5.5 mM glucose. The maximum rate of glucose absorption was approximately 20 pmol.mm-1.min-1 under these conditions. The concentration of glucose that supports 50% of the maximum rate of absorption, Km, was 0.6 mM. When tubules were perfused at flow rates of less than or equal to 2 nl.mm-1.min-1, the luminal glucose concentration reached a limiting value of 0.47 mM with 5.5 mM glucose in the bath. The glucose permeability was 3.1 X 10(-6) cm/s.

scholarly journals Small Intestinal Glucose Transport

1967 ◽  
Vol 50 (5) ◽  
pp. 1173-1182 ◽  
Author(s):  
Alan K. Rider ◽  
Harold P. Schedl ◽  
George Nokes ◽  
Streeter Shining
Keyword(s):  
Glucose Transport ◽  
Absorption Rate ◽  
Distal Segment ◽  
Glucose Absorption ◽  
In Vivo Studies ◽  
Intestinal Segments ◽  
Small Intestinal ◽  
Rate Limiting

Proximal and distal small intestinal segments of the rat were perfused in situ at two different rates with isotonic solutions containing glucose in concentrations ranging from 25 to 600 mg/100 ml. Absorption was measured as glucose disappearance rate from the lumen. Glucose absorption had not previously been studied at intraluminal concentrations above and below blood glucose. Absorption was more rapid from the proximal segment. In both segments absorption was independent of perfusion rate and of whether glucose was analyzed by counting 14C or by the Somogyi method. The latter finding suggests that of the unidirectional fluxes, flux out of the bowel is much greater than flux into the bowel. In contrast to the findings in previous studies neither segment showed rate-limiting kinetics, and the Michaelis-Menten analysis was not applicable. The form of the curve depicting absorption rate in relation to concentration differed between the two segments. At the higher concentrations absorption rate continued to increase much more rapidly in the proximal than in the distal segment. The observations could not be explained by known mechanisms of glucose transport and illustrate the difficulties of achieving biochemically and physiologically meaningful in vivo studies of intestinal absorption.

Angiotensin II Mediates Increased Small Intestinal Fluid Absorption with Extracellular Volume Depletion in the Rat*

Endocrinology ◽  
1984 ◽  
Vol 114 (5) ◽  
pp. 1692-1701 ◽  
Author(s):  
NIGEL R. LEVENS ◽  
SHIELA P. MARRISCOTTI ◽  
MICHAEL J. PEACH ◽  
KENNETH A. MUNDAY ◽  
ROBERT M. CAREY
Keyword(s):  
Angiotensin Ii ◽  
Extracellular Volume ◽  
Intestinal Fluid ◽  
Fluid Absorption ◽  
Volume Depletion ◽  
Small Intestinal

Relationship between interdigestive duodenal motility and fluid transport in humans

1990 ◽  
Vol 259 (3) ◽  
pp. G348-G354 ◽  
Author(s):  
H. Sjovall ◽  
I. Hagman ◽  
H. Abrahamsson
Keyword(s):  
Motor Activity ◽  
Phase Ii ◽  
Absorption Rate ◽  
Fluid Transport ◽  
Late Phase ◽  
Fluid Absorption ◽  
Amylase Release ◽  
Duodenal Fluid ◽  
Interdigestive Motility ◽  
Motility Cycle

In 22 healthy volunteers distal duodenal fluid absorption was related to the interdigestive motility cycle. Fluid absorption was measured with a triple-lumen perfusion technique, and motility was registered with a low-compliance pneumohydraulic system. Pancreatic and biliary secretions were estimated by measurement of bilirubin and amylase release into the duodenal segment. Duodenal fluid absorption rate changed during the interdigestive motility cycle; the highest absorption rate was registered during phase I (low-motor activity) and absorption rate then decreased in parallel with increasing motor activity during phase II (r = -0.69, P less than 0.001). In late phase II a net fluid secretion was frequently registered, together with an increased release of bilirubin into the duodenal lumen. This pattern was seen during perfusion with both glucose-containing (30 mM) and glucose-free solutions. The results show that duodenal fluid absorption rate changes markedly during the interdigestive motility cycle. This effect may be a hydrodnamic phenomenon or may be due to activation of a neural secretory mechanism during phase II.

Fluid and Solute Transport in CAPD Patients before and after Permanent Loss of Ultrafiltration Capacity

2005 ◽  
Vol 28 (10) ◽  
pp. 976-984 ◽  
Author(s):  
J. Waniewski ◽  
D. Sobiecka ◽  
M. DĘbowska ◽  
O. Heimbürger ◽  
A. Werynski ◽  
...  
Keyword(s):  
Solute Transport ◽  
Absorption Rate ◽  
Fluid Absorption ◽  
Transport Parameters ◽  
Normal Range ◽  
Peritoneal Transport ◽  
High K ◽  
Before And After ◽  
Permanent Loss ◽  
High Fluid

Background Two major types of permanent loss of ultrafiltration capacity (UFC) were previously distinguished among patients treated with CAPD: 1) type HDR with high diffusive peritoneal transport rate of small solutes and low osmotic conductance, but with normal fluid absorption rate, and 2) type HAR with high fluid absorption rate, but with normal diffusive peritoneal transport rate of small solutes and normal osmotic conductance. However, the detailed pattern of changes in peritoneal transport parameters in patients developing loss of ultrafiltration capacity is not known. Objective Analysis of solute and fluid transport parameters in the same patient before and after UFC loss. Patients Seven CAPD patients who had undergone repeated dwell studies, which were carried out before and/or after the onset of UFC loss. Methods Dialysis fluids (2 L) with glucose or a mixture of amino acids as osmotic agent at three basic tonicities were applied during 6 hour dwell studies. Fluid and solute transport parameters were previously shown not to be affected by these dialysis solutions (except by hypertonic amino acid-based solution). Intraperitoneal dialysate volume and fluid absorption rate were assessed using radiolabeled human serum albumin (RISA). Osmotic conductance (aOS) was estimated by a mathematical model as ultrafiltration rate induced by unit osmolality gradient. Diffusive mass transport coefficients, KBD, for glucose, urea, and creatinine were estimated using the modified Babb-Randerson-Farrell model. Results Five patients had increased KBD for small solutes after the onset of UFC loss, and three of them had decreased aOS, whereas two patients had normal aOS. In one of them, aOS decreased with time after the onset of UFC loss with concomitant normalization of glucose absorption. In all studies of these five patients the fluid absorption rate was within the normal range. Two other patients had increased fluid absorption rate (about 5 ml/min), and one of them also had increased KBD for small solutes, in two consecutive dwell studies in each patient with the second study being carried out at 1 and 7 months respectively after the first one. In all four studies in these two patients, the aOS was within the normal range. The sodium dip during dialysis with 3.86% glucose-based solution was lost, not only among most patients with UFC loss related to reduced osmotic conductance, but also in patients with increased KBD. Conclusions The occurrence of two major types of UFC loss was confirmed. However, a case of a mixed type of UFC loss with high fluid absorption rate and high KBD for small solutes, but normal osmotic conductance, and with normalization of initially high KBD for small solutes, linked with decreasing initially normal osmotic conductance, was also found. As a reduced sodium dip with hypertonic glucose solution is not only seen in patients with reduced osmotic conductance, it cannot reliably be used as a single measure of decreased aquaporin function. Permanent ultrafiltration capacity loss may be a dynamic phenomenon with a variety of alterations in peritoneal transport characteristics.

Peritoneal Fluid and Solute Transport with Different Polyglucose Formulations

1998 ◽  
Vol 18 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Tao Wang ◽  
Olof Heimbürger ◽  
Hui-Hong Cheng ◽  
Jonas Bergström ◽  
Bengt Lindholm
Keyword(s):  
Solute Transport ◽  
Peritoneal Cavity ◽  
Peritoneal Fluid ◽  
Absorption Rate ◽  
Glucose Solution ◽  
Ex Vivo ◽  
Elimination Rate ◽  
Fluid Absorption ◽  
Significant Difference ◽  
Glucose Polymer

Objective To study peritoneal fluid and solute transport characteristics using different polyglucose solutions with and without the addition of glucose. Design Thirty-one rats were divided into three groups. A 4-hour dwell study with frequent dialysate and blood samples was performed in each rat using 25 mL of 7.5% polyglucose solution (PG, n = 11),7.5% polyglucose + 0.35% glucose solution (PG1, n = 12), or 3.75% polyglucose + 1.93% glucose solution (PG2, n = 8). Radiolabeled human albumin (RISA) was added to the solutions as an intraperitoneal volume (IPV) marker. In addition, polyglucose degradation was evaluated ex vivo over 24 hours. Experimental Animals Thirty-one male Sprague Dawley rats (300 g) were used. Main Outcome Measures Fluid and solute (glucose, urea, sodium, potassium, and total protein) transport characteristics as well as changes in dialysate osmolality were evaluated. Results The IPV was higher in the PG1 and PG2 groups than in the PG group during the first 2 hours of the dwell. The IPV, in fact, decreased during the first hour of the dwell in the PG group. However, the net ultrafiltration at 4 hours tended to be lower in the PG2 (3.2 ± 1.5 mL) group compared to the PG (5.1 ± 2.3 mL) and the PG1 groups (5.2 ± 2.1 mL) (p = 0.07), and no significant difference was found between the PG and PG1 groups. Adding glucose to the PG solution increased the RISA elimination rate (KE, representing the fluid absorption rate from the peritoneal cavity): 25.5 ± 8.2, 37.5 ± 12.2, and 42.5 ± 8.9 μL/ min for the PG, PG1, and the PG2 group, respectively, p < 0.01. Dialysate osmolality (Dos) increased with the dwell time in the PG and PG1 groups but decreased in the PG2 group. The increase in Dos was partially due to the degradation of glucose polymer, which was supported by the marked increase in osmolality over 24 hours of incubation of PG solution with peritoneal fluid, ex vivo. The diffusive mass transport coefficient for the investigated solutes did not differ among the three groups (except for glucose, which was significantly lower in the PG group). The sieving coefficient for sodium was significantly higher in the PG group compared to the PG1 group (p < 0.05). Conclusion Our results suggest that, although there was an initial decrease in the intraperitoneal dialysate volume, significant amounts of fluid can be removed by polyglucose solution during a single 4-hour dwell in rats, despite the low osmolality of the solution. The positive fluid removal induced by the PG solution is partially due to the lower fluid absorption rate associated with this solution and may, to some extent, also be due to the degradation of glucose polymer within the peritoneal cavity, resulting in increased dialysate osmolality. The addition of glucose to the polyglucose solution does not seem to improve ultrafiltration in a 4-hour dwell in the rat model. However, the peritoneal fluid absorption rate may be increased, and peritoneal transport of glucose and sodium may be altered, by adding glucose to the polyglucose solution.

scholarly journals Absorption of L-histidine and glucose from the jejunum segment of the pig and its diurnal fluctuation

1975 ◽  
Vol 34 (2) ◽  
pp. 267-277 ◽  
Author(s):  
S. Furuya ◽  
S. Takahashi
Keyword(s):  
Flow Rate ◽  
Absorption Rate ◽  
Maximum Flow ◽  
Glucose Absorption ◽  
Test Material ◽  
Diurnal Fluctuation ◽  
Once Daily ◽  
Jejunum Segment

1. Flow rate of digesta and its components in the upper jejunum, and the absorption of L-histidine and glucose from the jejunum segment were measured in pigs fitted with three simple cannulas. The pigs were fed once daily at 08.30 hours.2. A maximum flow of digesta was obtained in the period 10.00–10.30 hours; the flow rate decreased with time after feeding, reaching a minimum in the period 22.00–22.30 hours.3. The absorption rate for L-histidine and glucose increased in a hyperbolic manner with increasing concentrations of infused test material, which ranged from 2.5 to 20 g/l for each material.4. L-histidine and glucose were absorbed nearly independently when perfused in combination. The absorption rates for glucose were significantly (P < 0.01) greater than the corresponding rates for L-histidine at each concentration of infusate.5. The absorption of both L-histidine and glucose expressed as a percentage of the amounts in the perfusate decreased with increasing flow rate of perfusate, from 400 to 800 ml/h. The increase in flow rate from 400 to 800 ml/h was associated with a 20% increase in L-histidine absorption rate; there was a 30% increase in glucose absorption rate when the flow rate was increased to 600 ml/h, but no further increase at 800 ml/h.6. The absorption of both L-histidine and glucose decreased with time after feeding; the absorption rates for L-histidine and glucose measured for the period 10.00–10.30 hours were 126 and 133%, respectively, of those measured for the period 22.00–22.30 hours.

Urea gradient-associated fluid absorption with sigma urea = 1 in rat terminal collecting duct

1990 ◽  
Vol 258 (5) ◽  
pp. F1173-F1180 ◽  
Author(s):  
C. L. Chou ◽  
J. M. Sands ◽  
H. Nonoguchi ◽  
M. A. Knepper
Keyword(s):  
Mathematical Model ◽  
Absorption Rate ◽  
Collecting Duct ◽  
Null Point ◽  
Absorption Measurement ◽  
Urea Transport ◽  
Fluid Absorption ◽  
A Value ◽  
Collecting Ducts ◽  
Isolated Rat

It has been proposed that inner medullary collecting ducts (IMCDs) can absorb fluid in the absence of a transepithelial osmolality gradient if a perfusate-to-bath urea gradient is present. Such a process has been suggested to be caused by a nonunity reflection coefficient for urea (sigma urea less than 1). However, our recent measurements of sigma urea yielded values not significantly different from 1.0. The present study was done to readdress the possibility of direct coupling of water and urea transport in the rat IMCD. Isolated rat terminal IMCD segments were studied in the presence of 10(-10) M vasopressin with the osmolality of the perfusate equal to that of the peritubular bath but with a perfusate-to-bath urea gradient (bath osmolality balanced with NaCl). We measured both fluid absorption rate and urea concentration in collected fluid and calculated the osmolality of the collected fluid. We observed rapid fluid absorption associated with substantial urea absorption. The urea absorption caused a large fall in the osmolality of the collected fluid with respect to the bath. Simulations with a mathematical model of an isolated perfused tubule revealed that the transepithelial osmolality gradient generated along the length of tubule (caused by urea absorption) was large enough to account for the fluid absorption. Measurement of sigma urea with the "zero-flux" (or null point) method revealed a value of 1.00 +/- 0.02. Thus we conclude that the observed fluid absorption is the result of a transepithelial osmolality gradient generated by rapid urea absorption and does not require sigma urea less than one.

Physiological changes in blood glucose affect appetite and pyloric motility during intraduodenal lipid infusion

1998 ◽  
Vol 275 (4) ◽  
pp. G797-G804 ◽  
Author(s):  
J. M. Andrews ◽  
C. K. Rayner ◽  
S. Doran ◽  
G. S. Hebbard ◽  
M. Horowitz
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Blood Glucose Concentration ◽  
Sensory Function ◽  
Fasting State ◽  
Lipid Infusion ◽  
Visual Analog Scales ◽  
Small Intestinal ◽  
Blood Glucose Concentrations ◽  
Pyloric Motility

We evaluated the effects of varying blood glucose concentration within the normal postprandial range and its interaction with small intestinal nutrients on antropyloric motility and appetite. Eight healthy males (19–40 yr) underwent paired studies, with a blood glucose level of 5 or 8 mmol/l. Manometry and visual analog scales were used to assess motility and appetite, during fasting and intraduodenal lipid infusion (1.5 kcal/min). In the fasting state, antral waves were suppressed at 8 mmol/l compared with 5 mmol/l ( P = 0.018). However, pyloric motility was no different between the two blood glucose concentrations. Hunger was no different at 5 mmol/l compared with 8 mmol/l, but fullness was greater at 8 mmol/l ( P = 0.01). During intraduodenal lipid infusion, antral waves were suppressed ( P < 0.035) and isolated pyloric pressure waves (IPPWs) were stimulated ( P < 0.02) compared with during the fasting state, with no difference between blood glucose concentrations, although the temporal patterning of IPPWs varied between blood glucose concentrations. The amplitude of IPPWs was greater at 5 mmol/l compared with 8 mmol/l ( P < 0.001), and hunger decreased at 8 mmol/l compared with 5 mmol/l ( P = 0.02). We conclude that “physiological” hyperglycemia modifies gastric motor and sensory function and that synergy exists between blood glucose concentration and small intestinal nutrients in modulating gastric motility and appetite.

Hyaluronan Preserves Peritoneal Membrane Transport Properties

2001 ◽  
Vol 21 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Qun-Ying Guo ◽  
Wen-Xing Peng ◽  
Hui-Hong Cheng ◽  
Ren-Gao Ye ◽  
Bengt Lindholm ◽  
...  
Keyword(s):  
Membrane Transport ◽  
Peritoneal Fluid ◽  
Absorption Rate ◽  
Control Group ◽  
Fluid Absorption ◽  
Peritoneal Membrane ◽  
Lymphatic Absorption ◽  
Dialysis Solution ◽  
Significant Difference ◽  
And Control

Background We have shown that intraperitoneal (IP) addition of hyaluronan (HA) in a single dwell study in rat could increase peritoneal fluid removal by decreasing the peritoneal fluid absorption rate. In this study, we investigated the impact of repeated use of HA on peritoneal membrane transport characteristics. Methods Twelve male Sprague–Dawley rats received a once-daily IP injection of 25 mL 4.25% glucose dialysis solution without (HP group, n = 6) or with 0.025% HA (HA group, n = 6) for 1 week. Forty-eight hours after the last injection, a 4 hour dwell using 25 mL 4.25% glucose dialysis solution with IP volume marker and frequent dialysate and blood samplings was performed in each rat as well as in rats that did not receive any injection (control group, n = 8). Results Although the IP volumes were significantly lower in the HP and HA groups compared to the control group, IP volume in the HA group was significantly higher than in the HP group. Net ultrafiltration at 4 hours was 5.6 ± 1.3 mL, 10.2 ± 1.8 mL, and 13.2 ± 0.6 mL for the H P, HA, and control group, respectively. The peritoneal fluid absorption rate decreased by 45% in the HA group compared to the HP group. There was no significant difference in peritoneal fluid absorption rate between the HA and the control group. No difference was found in the direct lymphatic absorption rate between the HP and HA groups [0.010 ± 0.003 mL/minute in the HP group and 0.011 ± 0.004 mL/min in the HA group] although they were both higher than that of the control group (0.004 ± 0.001 mL/min). The solute transport rates were in general significantly higher in the HP group compared to the HA and control groups, and there was no significant difference between the latter two groups, except that protein transport rate was significantly lower in the HA group compared to the control group. Conclusions The present study suggests that ( 1 ) repeated exposure to hypertonic glucose-based dialysis solution results in increased peritoneal solute transport rates, as well as increased peritoneal fluid absorption rates; and ( 2 ) these changes, reflecting a highly permeable peritoneal membrane, were ameliorated by repeated IP addition of hyaluronan. The similar changes in the direct lymphatic absorption rate in rats that received daily IP injection of dialysis solution suggest that direct peritoneal lymphatic absorption was not influenced by hyaluronan.

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