Glucose-coupled sodium absorption in the developing rat colon

1986 ◽  
Vol 250 (2) ◽  
pp. G221-G226 ◽  
Author(s):  
G. D. Potter ◽  
S. M. Burlingame
Keyword(s):  
Amino Acid ◽  
Dry Weight ◽  
Rat Colon ◽  
Sodium Absorption ◽  
Na Transport ◽  
Fetal Rat ◽  
Fetal Rats ◽  
The Difference ◽  
Developing Rat

The developing mammalian colon is lined by villi and is capable of glucose and amino acid absorption at birth in the rat. Neither the point at which this capacity is lost nor the effect of the capacity for glucose transport on Na absorption has been studied. We have now applied a system for perfusion of the lumen of in vitro segments of colon from 20-day-old fetal rats, and pups between 6 and 8 days old, to measure Na transport and transepithelial potential difference (PD). The lumens of colons from animals at both ages were perfused with solutions containing glucose or mannitol and 22Na. Net Na transport was 164 +/- 37 mu eq X h-1 X g dry weight tissue perfused-1, as determined by the difference between lumen-to-bath and bath-to-lumen flux in fetal rat colons at day 20. Glucose increased the lumen-to-bath flux by 90 +/- 35 mu eq X h-1 X g-1. PD was immediately increased from -1.7 +/- 0.16 to -8.0 +/- 0.96 mV (lumen with respect to bath) by the addition of glucose, and the change in PD was inhibited by 10(-4) M phlorizin. The PD response to glucose was lost at day 2 of life, but the villus epithelium persisted. Amiloride, 10(-4) M, did not alter PD or Na transport at either age. We conclude that the fetal rat colon exhibits glucose-dependent Na flux at birth but that this property is lost by 6-8 days.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals 131 MODIFICATION OF AMINO ACID CONCENTRATIONS IN MEDIUM BY PIG EMBRYOS FROM THE ZYGOTE TO THE BLASTOCYST STAGE

2005 ◽  
Vol 17 (2) ◽  
pp. 216
Author(s):  
P. Booth ◽  
T. Watson ◽  
H. Leese
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Embryonic Development ◽  
Amino Acid Profile ◽  
Blastocyst Stage ◽  
Morula Stage ◽  
Amino Acid Profiles ◽  
The Difference ◽  
Amino Acid Concentrations

Pre-implantation embryos can produce and consume amino acids in a manner dependent upon stage of embryonic development (Partridge and Leese 1996 Reprod. Fert. Dev. 8, 945) that may also be predictive of subsequent viability (Houghton et al. 2002 Hum. Reprod. 17, 999). To examine these relationships in the pig, the appearance or depletion of 18 amino acids from a presumptive near-physiological mixture was determined by HPLC in porcine in vitro-produced embryos from the zygote to the blastocyst stage. Cumulus oocyte complexes derived from slaughterhouse prepubertal pig ovaries were matured for 40 h in modified TCM-199 before being fertilized (Day 0) with frozen thawed semen in tris-based medium. After 6 h, presumptive zygotes were denuded and cultured in groups of 20 in NCSU medium modified to contain a physiological mixture of 18 amino acids including 0.1 mM glutamine (NCSUaa). Groups of 2–10 embryos (dependent on stage) were removed on Day 0 (1 cell), Day 1 (2- and 4-cell), Day 4 (compact morula), and Day 6 (blastocyst) and placed in 4 μL NCSUaa for 24 h. After incubation, the embryos were removed and the medium analyzed by HPLC. Each stage was replicated 3–9 times. Since amino acid profiles of 2- and 4-cell embryos were not different, data were combined. Overall, arginine (1.19 ± 0.33), glutamine (0.78 ± 0.34) and threonine (0.05 ± 0.04) were significantly (P < 0.01) depleted from the medium whereas alanine (0.21 ± 0.1), glycine (0.20 ± 0.06), asparagine (0.13 ± 0.5), lysine (0.1 ± 0.03), isoleucine (0.08 ± 0.01), valine (0.05 ± 0.01), leucine (0.04 ± 0.02), phenylalanine (0.03 ± 0.01), and histidine (0.02 ± 0.04) significantly (P < 0.05) accumulated (mean of the 4 sampling timepoints; all values pmol/embryo/h ± SEM). The difference between amino acid accumulation and depletion (balance) was approximately equivalent between Day 0 and the morula stage although turnover (sum of depletion and accumulation) steadily decreased during this period from 3.1 on Day 0 to 1.35 pmol/embryo/h at the morula stage. However, at the blastocyst stage, turnover and balance increased to 6.32 and 2.42 pmol/embryo/h, respectively, i.e. net appearance occurred. Notable changes in amino acid profile during development included decreases in accumulation of asparagine, glutamate, and glycine in the medium and the depletion of glutamine over Days 0, 1, and 4, followed by reversal of these trends by Day 6. These data suggest that pig embryos can alter the accumulation and depletion rates of amino acids in a manner that is dependent on the specific amino acid and the stage of embryonic development. This work was supported by BBSRC.

Glucose absorption by in vitro perfused colon of the fetal rat

1983 ◽  
Vol 245 (3) ◽  
pp. G424-G430 ◽  
Author(s):  
G. D. Potter ◽  
K. L. Schmidt ◽  
R. Lester
Keyword(s):  
Small Bowel ◽  
Average Molecular Weight ◽  
Glucose Absorption ◽  
Physiological Solution ◽  
Rat Colon ◽  
Transmission Electron ◽  
Fetal Rat ◽  
Luminal Perfusion ◽  
And Control

The anatomic configuration of fetal rat colon resembles that of the small bowel. Accordingly, glucose and amino acid absorption were measured in order to see whether the fetal rat colon resembled the small bowel functionally. In vitro luminal perfusion of the fetal rat colon at 20 days of gestation was employed to measure the rate of glucose and L-alanine absorption and the unidirectional flux rates of 3-O-methylglucose (3-O-MG). The colon was mounted between pipettes in a heated oxygenated bath and perfused with the solute to be studied dissolved in buffered physiological solution and polyethylene glycol with average molecular weight of 4,000 (PEG) as a nonabsorbable marker substance. The PEG was not transported and did not diffuse across fetal colon. Scanning and transmission electron microscopy of perfused and control colon showed the presence of villi and the preservation of mucosal anatomy during perfusion. Glucose was absorbed at 173 +/- 16 mumol . h-1 . g-1 (8) and absorption was abolished in Na-free solution. 3-O-MG flux was 40 +/- 7 mumol . h-1 . g-1 (8) from lumen to bath and 7 +/- 1 mumol . h-1 . g-1 (8) from bath to lumen. L-Alanine flux was 130 +/- 15 mumol . h-1 . g-1 (8) from lumen to bath and 18 +/- 4 mumol . h-1 . g-1 (5) from bath to lumen, and the lumen-to-bath flux was only partially abolished by Na-free solutions.

Effect of glucose on insulin biosynthesis and β cell ultrastructure in cultured fetal rat pancreas

1984 ◽  
Vol 100 (2) ◽  
pp. 155-160 ◽  
Author(s):  
R. D. G. Milner ◽  
A. Cser ◽  
G. H. Cope
Keyword(s):  
Cell Ultrastructure ◽  
Insulin Biosynthesis ◽  
Cell Nuclei ◽  
Β Cell ◽  
Absolute Volume ◽  
Fetal Rat ◽  
Insulin Granules ◽  
Fetal Rats ◽  
Exocrine Cell

ABSTRACT Pancreatic rudiments from 14-day fetal rats were cultured whole for 8 days in medium containing 5·5 or 16·5 mmol glucose/l (1G or 3G medium). Rudiments grown in 3G medium (3G cells) contained more DNA and insulin than those grown in 1G medium (1G cells) but there was no alteration in the insulin/DNA ratio or the fractional area of the rudiment occupied by insulin-containing cells. Morphometric analysis of ultrastructure revealed that the β cells grown in 3G medium were smaller and had smaller nuclei than those grown in 1G medium. The size of exocrine cell nuclei in 1G or 3G medium was similar. Insulin granules occupied a greater proportion of the cytoplasmic volume in rudiments grown in 3G medium although the mean absolute volume of insulin granules per cell grown in 1G and 3G media was similar. Hence the residual cytoplasmic volume (cell—nucleus and granules) of 3G cells was less than that of 1G cells. Insulin granules from 3G cells had smaller granule sacs and cores than those from 1G cells. It is concluded that glucose stimulates the growth of rat fetal pancreas in vitro and has important effects on β cell ultrastructure. J. Endocr. (1984) 100, 155–160

Amino acid fluxes in rat thin limb segments of Henle’s loop during in vitro microperfusion

1999 ◽  
Vol 277 (2) ◽  
pp. F204-F210 ◽  
Author(s):  
Olga H. Brokl ◽  
William H. Dantzler
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Apparent Movement ◽  
Transepithelial Transport ◽  
Acid Transport ◽  
Henle's Loop ◽  
Vasa Recta ◽  
The Difference

Amino acids are apparently recycled between loops of Henle and vasa recta in the rat papilla in vivo. To examine more closely papillary amino acid transport, we measured transepithelial fluxes ofl-[14C]alanine and [14C]taurine in thin limbs of Henle’s loops isolated from rat papilla and perfused in vitro. In descending thin limbs (DTL) in vitro, unidirectional bath-to-lumen fluxes tended to exceed unidirectional lumen-to-bath fluxes for both radiolabeled amino acids, although the difference was statistically significant only for taurine. In ascending thin limbs (ATL) in vitro, unidirectional lumen-to-bath fluxes tended to exceed unidirectional bath-to-lumen fluxes, although the difference was again statistically significant only for taurine. These results are compatible with apparent directional movements of amino acids in vivo. However, none of the unidirectional fluxes was saturable or inhibitable, an observation compatible with apparent reabsorption from the ATL in vivo but not compatible with apparent movement from vasa recta to DTL in vivo. There was no evidence of net active transepithelial transport when concentrations of radiolabeled amino acids were matched on both sides of perfused tubule segments. These data suggest that regulation of amino acid movement in vivo may involve the vasa recta, not the DTL of Henle’s loops. The data also suggest that transepithelial movement of amino acids in thin limbs of Henle’s loop may occur via a paracellular route.

Stimulation of aromatase activity in the fetal rat testis by cyclic AMP and FSH

1988 ◽  
Vol 118 (3) ◽  
pp. 485-489 ◽  
Author(s):  
J.-P. Weniger ◽  
A. Zeis
Keyword(s):  
Cyclic Amp ◽  
Specific Activity ◽  
Isotopic Dilution ◽  
Aromatase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Rat Testis ◽  
Fetal Rat ◽  
Fetal Rats ◽  
Stimulation Of

ABSTRACT The effect of dibutyryl cyclic AMP and FSH on oestrogen biosynthesis was investigated in testes from 18- to 21-day-old fetal rats cultured in vitro in the presence of tritiated testosterone. Oestrone and oestradiol concentrations were measured by determination of constant specific activity after isotopic dilution. Dibutyryl cyclic AMP and FSH markedly stimulated the conversion of testosterone into both oestrone and oestradiol at all stages studied. Oestradiol synthesis was stimulated by two- to sevenfold, while stimulation of oestrone synthesis was even greater. The results demonstrate that the aromatase enzyme system of the fetal rat testis responds to cyclic AMP and FSH. J. Endocr. (1988) 118, 485–489

scholarly journals Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain

2019 ◽  
Author(s):  
Lirong Chen ◽  
Yuqiu Guo ◽  
Xiaoyue Li ◽  
Kuijie Gong ◽  
Kaichang Liu
Keyword(s):  
Radical Scavenging ◽  
Dry Weight ◽  
Sodium Cholate ◽  
Free Form ◽  
Functional Activities ◽  
Free Phenolics ◽  
The Difference ◽  
Different Color ◽  
Waxy Corn

Abstract The polyphenol distribution in fresh waxy corns of different color varieties and their functional activities, which may be useful for treating various chronic diseases, were investigated. The in vitro antioxidant activity, and hypoglycemic and hypocholesterolemic effects of the free and bound corn phenolics were determined to evaluate the edible value of fresh waxy corn. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 6637.73 μg/g DW (dry weight), which was slightly higher (p >0.05) than that of the total bound form (6276.65 μg/g DW). The total free flavonoid content was 5850.09 μg/g DW, which was higher (p < 0.05) than that of the total bound form (4874.51μg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86-100% and 70-78% of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100% of the ferric reducing capacity. The free phenolics in fresh waxy corn showed significantly better (p< 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed significantly better (p < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.

Regulation of amiloride-sensitive electrogenic sodium transport in the rat colon by steroid hormones

1985 ◽  
Vol 248 (1) ◽  
pp. G124-G132 ◽  
Author(s):  
P. C. Will ◽  
R. N. Cortright ◽  
R. C. DeLisle ◽  
J. G. Douglas ◽  
U. Hopfer
Keyword(s):  
Sodium Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Serum Levels ◽  
Rat Colon ◽  
Sodium Absorption ◽  
Sodium Deficiency ◽  
Synthetic Glucocorticoids

The role of steroids in the regulation of colonic sodium transport was examined by infusing steroids into adrenalectomized (ADX) rats and evaluating the short-circuit current (ISC) in vitro. Amiloride-sensitive ISC was induced by aldosterone and corticosterone with half-maximal doses (ED50) of 2 and 260 micrograms X kg-1 X h-1), respectively. Synthetic glucocorticoids such as methylprednisolone (33 mg/kg) and dexamethasone (ED50 = 30 micrograms X kg-1 X h-1) were also effective. Supramaximal doses of aldosterone (7.5 times ED50) for 24 h increased the total ISC (7-fold), the amiloride-sensitive ISC (366-fold), and the conductance (2-fold), as well as the potassium-stimulated phosphatase activity (2-fold) (reported previously). Compared with aldosterone, supramaximal doses of dexamethasone (4 times ED50) produced greater increases in the total ISC (15-fold) and the amiloride-sensitive ISC (674-fold). In contrast to aldosterone, dexamethasone also increased the amiloride-insensitive ISC (3-fold). Glucocorticoid action was not mediated by insulin since the ISC from diabetic ADX rats was increased by dexamethasone to a similar extent (11-fold) as in nondiabetic rats. Estradiol, progesterone, and testosterone did not stimulate the colonic ISC of ADX rats. The ED50 values of corticosterone and aldosterone, measured in terms of amiloride-sensitive sodium transport, produced serum levels that were slightly above those of unstressed, adrenal-intact animals and thus must be considered physiological. It is concluded that at physiological levels both steroids may mediate amiloride-sensitive sodium transport in the rat colon. However, as judged from changes in serum steroid levels, aldosterone is the physiological regulator of elevated sodium absorption in sodium deficiency.

Phytotoxicity of 2,4-D and 2,4-Dichlorophenol to Red Clover (Trifolium pratense)

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 825-829 ◽  
Author(s):  
S. G. Taylor ◽  
D. G. Shilling ◽  
K. H. Quesenberry ◽  
G. R. Chaudhry
Keyword(s):  
Trifolium Pratense ◽  
Callus Tissue ◽  
Red Clover ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
The Difference ◽  
Plant Level

Whole plant and tissue culture experiments were conducted to determine the difference in phytotoxicity of 2,4-D and its metabolite, 2,4-DCP, to red clover. At the whole plant level, the mean concentration of 2,4-DCP (10 mM) required to cause 50% growth inhibition (I50) of shoot dry weight was 24 times greater than for 2,4-D (0.42 mM). Using callus tissue, the I50value for 2,4-DCP (0.28 mM) was 22 times greater than for 2,4-D (0.013 mM) based on dry weights. The callus tissue was 36 and 32 times more sensitive to 2,4-DCP and 2,4-D than shoot tissue based on dry weights, respectively. These data indicate that 2,4-DCP was less phytotoxic than 2,4-D to red clover both in vitro and in vivo.

Na+-dependent H+ efflux from proximal tubule: evidence for reversible Na+-H+ exchange

1981 ◽  
Vol 241 (4) ◽  
pp. F380-F385 ◽  
Author(s):  
G. J. Schwartz
Keyword(s):  
Proximal Tubule ◽  
Buffer Capacity ◽  
Rabbit Kidney ◽  
Organic Solutes ◽  
Fluid Flow Rate ◽  
Na Transport ◽  
The Difference ◽  
Convoluted Tubules ◽  
Reducing Energy

Removal of Na+ or addition of ouabain inhibits HCO3(-) and Na+ absorption in rabbit proximal tubule, a finding suggestive of Na+-H+ coupling. However, inhibition of Na+ transport might decrease H+ secretion by reducing energy metabolism rather than by inhibiting Na+-H+ exchange directly. H+ disappearance from the luminal fluid, which depends on direction and magnitude of Na+ gradient, should be a function of cell Na+, independent of cellular metabolism. If cell Na+ is increased by ouabain, H+ disappearance should increase; when cell Na+ is reduced by Na+ removal, less H+ should level the lumen for a given pH difference. Superficial early proximal convoluted tubules were dissected from rabbit kidney and perfused rapidly in vitro with CO2(-) and HCO3(-)-free solutions (pH 6.45). The bath resembled perfusate except that the pH was 7.4 and contained 6 g/dl of albumin. H+ efflux was calculated from the difference in pH between perfused and collected fluid, flow rate, and buffer capacity of the perfusate. When 145 mM Na+ was present in perfusate and bath, H+ efflux was 5.3 +/- 0.4 pmol . cm-1 . s-1 and increased by 39 +/- 16% when ouabain was added to the bath. Replacement of Na+ by choline or Li+ caused a 44 +/- 7% decrease in H+ efflux. Removal of luminal organic solutes markedly reduced H+ efflux; however, it was still enhanced by addition of ouabain to the bath. Even in the absence of Na+ or luminal organic solutes, a substantial apparent H+ leak permeability exists. Addition of 10(-4) M amiloride to a 10 mM Na+ medium caused a 34 +/- 6% reduction in H+ efflux. The results indicate that H+ transport in the proximal tubule is mediated, at least in part, by a reversible Na+-H+ exchanger driven by the difference between H+ and Na+ gradients.

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