scholarly journals The transmission of −125-I-labelled immunoglobulin G by proximal and distal regions of the small intestine of 16-day-old rats.

1975 ◽  
Vol 245 (1) ◽  
pp. 249-259 ◽  
Author(s):  
B Morris
Keyword(s):  
Small Intestine ◽  
Immunoglobulin G ◽  
Old Rats

scholarly journals Distribution of immunoglobulin G receptors in the small intestine of the young rat.

1980 ◽  
Vol 85 (1) ◽  
pp. 18-32 ◽  
Author(s):  
R Rodewald
Keyword(s):  
Small Intestine ◽  
Immunoglobulin G ◽  
Specific Binding ◽  
Proximal Jejunum ◽  
Luminal Surface ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Absorptive Cells ◽  
Igg Receptors ◽  
Old Rats

Conjugates of horseradish peroxidase (HRP) and immunoglobulin G (IgG) were used to map the distribution of cell surface receptors that can bind IgG at 0 degrees C within the small intestine of 10-12-d-old rats. Luminal receptors are present only within the duodenum and proximal jejunum. In these locations, receptors are limited to absorptive cells that line the upper portion of individual villi. Near villus tips, receptors are relatively evenly distributed over the entire luminal plasmalemma. In the midregion of villi, receptors are unevenly distributed over the luminal surface. Receptors (a) specifically bind rat and rabbit IgG, (b) recognize the Fc portion of the immunoglobulins, and (c) bind at pH 6.0 but not pH 7.4. To determine whether IgG receptors are confined to the luminal portion of the plasmalemma, intact epithelial cells were isolated from the proximal intestine of 10-12-d-old rats and incubated with HRP conjugates at 0 degree C. The specific binding of rat IgG-HRP to cells at pH 6.0 indicates that IgG receptors, which are functionally similar to those found on the luminal surface, are also present over the entire abluminal surface of absorptive cells. These results are consistent with the transport of IgG to the abluminal plasma membrane in the form of IgG-receptor complexes on the surface of vesicles. Exposure of these complexes to the serosal plasma, which is presumably at pH 7.4, would cause release of IgG from the receptors. To assess possible inward movement of vesicles from the abluminal surface after discharge of IgG, intravenously injected HRP was used as a space-filling tracer in the serosal plasma. HRP could be visualized within the coated and tubular vesicles responsible for transport of IgG in the opposite direction. These vesicles may, therefore, provide a pathway whereby receptors shuttle between the luminal and abluminal surfaces of cells.

scholarly journals Phosphatidylcholine synthesis in the developing small intestine

1980 ◽  
Vol 186 (2) ◽  
pp. 399-403 ◽  
Author(s):  
P G Holtzapple ◽  
C M Starr ◽  
T Morck
Keyword(s):  
Small Intestine ◽  
Oleic Acid ◽  
Steady State ◽  
Adult Rats ◽  
Acyltransferase Activity ◽  
Acid Incorporation ◽  
Old Rats ◽  
Phosphatidylcholine Synthesis

1. Phosphatidylcholine synthesis in the foetal, newborn and adult small intestine of rats was studied by determination of cytidine diphosphocholine-1,2-diacylglycerocholine phosphotransferase (cholinephosphotransferase) and acyl-CoA-1-acyl-sn-glycerol-3-phosphocholine acyltransferase (lysophosphatidylcholine acyltransferase) activities and the incorporation of [1-14C]oleic acid into phosphatidylcholine. 2. Cholinephosphotransferase activity was low in foetal jejunum and ileum, increased 3-4 fold in the ileum by 6 days of age and by 12 days in the jejunum. Jejunal activity remained constant throughout weaning; ileal activity gradually decreased to values 25% of that of the jejunum. 3. Lysophosphatidylcholine acyltransferase activity was high in foetal jejunum and ileum, decreased 70% immediately after birth in the jejunum and increased to adult values by 12 days of age. Ileal activity decreased by 20% after birth, but decreased more rapidly at weaning to 30% of the activity in jejunum. 4. Initial rates and steady-state incorporation of [1-14C]oleic acid into phosphatidylcholine by jejunal rings of 10 day-old rats exceeded that observed in jejunal rings from adult rats by 2-4-fold. 5. In the postnatal jejunum, neither cholinephosphotransferase and lysophosphatidylcholine acyltransferase activities nor oleic acid incorporation were stimulated by cortisone administration in vivo.

Development and tissue distribution of sucrase-isomaltase mRNA in rats

1990 ◽  
Vol 258 (1) ◽  
pp. G52-G58 ◽  
Author(s):  
L. L. Leeper ◽  
S. J. Henning
Keyword(s):  
Enzyme Activity ◽  
Small Intestine ◽  
Northern Blot ◽  
Blot Analysis ◽  
Molecular Basis ◽  
Northern Blot Analysis ◽  
Sucrase Activity ◽  
Old Rats ◽  
Two Parameters ◽  
Precocious Development

Previous studies of sucrase-isomaltase (SI) activities have shown this complex to be absent in the suckling rat and to appear during the weaning period. We describe here the cloning of a heterologous SI cDNA and its use for the quantitation of SI mRNA as a first step toward understanding the molecular basis of SI development. A survey of RNA from 12 tissues of mature rats by Northern blot analysis showed a 6-kb band of SI mRNA only in the small intestine. Within the latter, both sucrase activity and SI mRNA peaked in the jejunum. Assay of jejunal tissue from developing rats showed sucrase activity and SI mRNA to be first detectable at 18 days, to rise in parallel through 24 days, and then to diverge a little (enzyme activity being lower) by 36 days. When glucocorticoid was administered to 10-day-old rats, neither sucrase activity nor SI mRNA was detectable 12 h later. Both parameters were readily detected 24 h postinjection, although the mRNA had risen relatively more than the enzyme activity. The two parameters increased in concert through 5 days postinjection and then plateaued. We conclude that, with respect to distribution along the intestine and to normal and precocious development, activities of SI in the rat are determined primarily by the abundance of its mRNA.

scholarly journals Intestinal neuraminidase activity of suckling rats and other mammals. Relationship to the sialic acid content of milk

1978 ◽  
Vol 170 (2) ◽  
pp. 407-413 ◽  
Author(s):  
J J Dickson ◽  
M Messer
Keyword(s):  
Small Intestine ◽  
Sialic Acid ◽  
Gastric Mucosa ◽  
Acid Content ◽  
Significant Positive Correlation ◽  
Post Partum ◽  
Sialic Acid Content ◽  
Neuraminidase Activity ◽  
Stage Of Lactation ◽  
Old Rats

1. The neuraminidase activity of homogenates of the mucosa of the middle and distal thirds of the small intestine of rats increased about 5-fold between birth and 4 to 8 days of age, and then gradually declined to the much lower adult activity by 24 days. No comparable changes occurred in the proximal third. 2. In 8-day-old rats, the neuraminidase activity of the middle and distal thirds of the small intestine was about 10 times greater than that of the proximal third, 20 times greater than that of the colon and at least 100 times greater than that of the liver, brain, gastric mucosa or pancreas. 3. In all other species investigated (mice, rabbits, cats and guinea pigs), the neuraminidase activity of the middle and distal thirds of the small intestine was greater in suckling animals than in adults. 4. The sialic acid content of rat milk increased about 2-fold between birth and 8 days post partum and then declined. 5. There was a highly significant positive correlation between the intestinal neuraminidase activity of suckling animals of various species and ages and the sialic acid content of milk obtained from the corresponding species and stage of lactation. 6. It is suggested that the intestinal neuraminidase of suckling mammals functions primarily to remove sialic acid from various components of milk, thus providing sialic acid for the synthesis of sialoglycoproteins and gangliosides by the young.

Elevated iron absorption in the neonatal rat reflects high expression of iron transport genes in the distal alimentary tract

2007 ◽  
Vol 293 (3) ◽  
pp. G525-G531 ◽  
Author(s):  
David M. Frazer ◽  
Sarah J. Wilkins ◽  
Gregory J. Anderson
Keyword(s):  
Small Intestine ◽  
Iron Absorption ◽  
Neonatal Rat ◽  
Ribonuclease Protection Assay ◽  
Intestinal Iron Absorption ◽  
Distal Small Intestine ◽  
Hepatic Expression ◽  
Genes Encoding ◽  
Old Rats ◽  
Ribonuclease Protection

Intestinal iron absorption is extremely high in neonatal mammals but falls rapidly to adult levels following weaning. The aim of this study was to investigate the molecular basis of this elevated neonatal absorption using the rat as an experimental model. RNA was extracted from various sections of the intestine of 10-, 15-, 20-, 25-, and 300-day-old rats and the expression of the genes encoding DMT1 ( Slc11a2), ferroportin ( Slc40a1), Cybrd1 ( Cybrd1), and hephaestin ( heph) determined by ribonuclease protection assay. The hepatic expression of Hamp was studied at the same ages. Iron absorption was examined by following 59Fe uptake in both whole animals and in isolated intestinal loops. Slc11a2, Slc40a1, and Cybrd1 mRNAs were highly expressed in all regions of the small intestine and colon studied in suckling rats. However, after weaning, when iron absorption declined significantly, strong expression was retained only in the duodenum. No change in hephaestin mRNA occurred in any part of the digestive tract. In the distal small intestine and colon, Slc40a1 expression most closely followed the change in absorption that occurred after weaning. Hamp expression was low during the neonatal period and increased to adult levels following weaning. Our results suggest that the distal small intestine and colon contribute significantly to the high intestinal iron absorption seen in neonatal animals and that this reflects increased expression of the iron transporters, particularly Slc40a1.

EFFECT OF THYROIDECTOMY ON THE ACTIVITY OF α-GLUCOSIDASES AND ACID HYDROLASES IN THE SMALL INTESTINE OF RATS DURING WEANING

1975 ◽  
Vol 66 (1) ◽  
pp. 31-36 ◽  
Author(s):  
OTAKAR KOLDOVSKÝ ◽  
JOCELYN JUMAWAN ◽  
MICHAEL PALMIERI
Keyword(s):  
Body Weight ◽  
Small Intestine ◽  
Acid Hydrolases ◽  
Enzyme Profile ◽  
The Third ◽  
Maltase Activity ◽  
Old Rats

SUMMARY Adrenalectomy performed on 14-day-old rats delayed the usual increase of sucrase and maltase activity as well as the decrease of acid β-galactosidase, β-glucuronidase and N-acetyl-β-glucosaminidase activity during the third postnatal week. Since these changes were only delayed, the role of the thyroid was explored. Thyroidectomy performed simultaneously with adrenalectomy on 14-day-old rats did not influence the increase in body weight and growth of the small intestine (already slowed down by adrenalectomy), but caused a further substantial delay in the maturation of the enzyme profile of the small intestine. Our results indicate that the thyroid is involved in regulation of the hydrolases studied.

scholarly journals Group A Rotavirus Infection and Age-Dependent Diarrheal Disease in Rats: a New Animal Model To Study the Pathophysiology of Rotavirus Infection

2002 ◽  
Vol 76 (1) ◽  
pp. 41-57 ◽  
Author(s):  
Max Ciarlet ◽  
Margaret E. Conner ◽  
Milton J. Finegold ◽  
Mary K. Estes
Keyword(s):  
Animal Model ◽  
Small Intestine ◽  
Virus Antigen ◽  
Neonatal Rats ◽  
Histopathological Changes ◽  
Rotavirus Infection ◽  
Age Dependent ◽  
Group A Rotaviruses ◽  
Group A ◽  
Old Rats

ABSTRACT Group A rotaviruses are major pathogens causing acute gastroenteritis in children and animals. To determine if group A rotavirus replicates and induces disease in rats, antibody-negative Lewis neonatal or adult rats were inoculated orally with tissue culture-adapted human (Wa, WI61, and HAL1166), simian (rhesus rotavirus [RRV] and SA11), bovine (WC3), lapine (ALA), or porcine (OSU) rotavirus strains, wild-type murine (ECwt) rotavirus strain, or phosphate-buffered saline (PBS). Rotavirus infection in rats was evaluated by (i) clinical findings, (ii) virus antigen shedding or infectious virus titers in the feces or intestinal contents measured by enzyme-linked immunosorbent assay or fluorescent-focus assay, (iii) histopathological changes in the small intestine, (iv) distribution of rotavirus antigen in small-intestine sections by immunofluorescence, and (v) growth rate. Rotavirus infection of 5-day-old but not ≥21-day-old rats resulted in diarrhea that lasted from 1 to 10 days postinoculation. The severity of disease and spread of infection to naÏve littermates differed depending on the virus strain used for inoculation. The duration of virus antigen shedding following infection was considerably prolonged (up to 10 days) in neonatal rats compared to that in 21-day-old rats (1 or 2 days). Based on lack of virus antigen shedding and disease induction, the murine ECwt rotavirus was the only strain tested that did not infect rats. Histopathological changes in the small-intestine mucosa of 5-day-old RRV-inoculated rats but not of PBS-inoculated rats was limited to extensive enterocyte vacuolation in the ileum. In RRV-inoculated neonatal rats, rotavirus antigen was detected in the epithelial cells on the upper half of the intestinal villi of the jejunum and ileum. In addition, infection of neonatal rats with RRV but not with PBS resulted in reduced weight gain. Rats infected with group A rotaviruses provide a new animal model with unique features amenable to investigate rotavirus pathogenesis and the molecular mechanisms of intestinal development, including physiological factors that may regulate age-dependent rotavirus-induced diarrhea.

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