The effect of potassium cyanide on p-nitroanisole O-demethylation in perfused rat livers has been examined. Cyanide (2 mM), an inhibitor of cytochrome oxidase, diminished p-nitroanisole O-demethylation by 50-75% in perfused livers from normal and phenobarbital-treated rats, but had much less effect on hepatic microsomal p-nitroanisole O-demethylation. The inhibition was also ...

Following perfusion fixation of livers from fetal, neonatal, and adult sheep, the ultrastructure of the fenestrated sinusoidal endothelium was examined. In contrast to an earlier report which utilized immersion fixation, we found the fenestrae to be unoccluded by diaphragms or basal lamina, thus offering only a discontinuous barrier between the ...

The relative roles of the kidney and liver as a source of Ep in a fully compensated hemolytic state were investigated. A compensated hemolytic anemia was induced in rats by injections of PHZ over a 6-week period. Verification of a fully compensated hemolytic state was established by MCV, MCH, MCHC, ...

Insulin and glucagon stimulate bile production in the intact rat without affecting the biliary excretion rate of bile acids. This effect was not demonstrable in rat liver perfused with human erythrocytes suspended in a Krebs-Henseleit-bicarbonate buffer at a hematocrit of about 18%. The present experiments demonstrate that the choleretic effect ...

The portal circulation of diethylnitrosamine-initiated nodules (0.5 to 7 mm in diameter) was studied in rat livers perfused exclusively via the portal vein. Microlight guides were placed on normal and nodular tissue on the capsular surface of the liver to measure pyridine nucleotide fluorescence (366 leads to 450 nm). When ...

Isolated livers of normal and hypophysectomized (hypox) rats with or without GH replacement therapy were perfused in an erythrocyte-free recirculating perfusion system for 4 h in the presence of [35S]cysteine. Albumin secretion and synthesis increased in a parallel and linear fashion over 4 h. The albumin secretion rates were 0.53 ...

5-Benzylacyclouridine (BAU) is a specific inhibitor of uridine phosphorylase, the first enzyme in the catabolism of uridine. It was found that 20 and 100 microM BAU dramatically reduced the rapid clearance of trace amounts of either [14C]uridine or hyperphysiologic concentrations of non-labeled uridine by the isolated rat liver perfused with ...

An analysis of 239Pu-labelled protein complexes in serum and liver cytosol fractions prepared from rats injected intravenously with 239Pu-citrate indicated that among the possible metal-binding proteins, ferritin, transferrin and metallothionein, 239Pu was bound almost exclusively to transferrin. The method employed for the quantitative determination of 239Pu-transferrin was chromatography on immobilized ...

From the results obtained in perfused rat hearts, Frick and Lowenstein proposed that ecto-5'-nucleotidase catalyzes a vectorial reaction in which AMP hydrolysis is accompanied by transfer of adenosine across the cell membrane (Frick, G.P., and Lowenstein, J.M. (1978) J. Biol. Chem. 253, 1240-1244). We have examined by the use of ...

A procedure for the study of NE metabolism in the intact rat brain is described. The method involves ventriculocisternal perfusion of the adult male rat with artificial CSF containing [3H]NE. Radioactivity in the perfusate associated with NE and its metabolites 3,4-dihydroxymandelic acid (DOMA), 3,4-dihydroxyphenylethyleneglycol (DHPG), 3-methoxy-4-hydroxymandelic acid (VMA), 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), ...

Gluconeogenic and oxidative capabilities with lactate as a substrate were studied in perfused livers isolated from rats in late sepsis. Glucose release in the presence of 5 mM lactate was significantly depressed in livers from septic rats. When gluconeogenesis was stimulated by phenylephrine, livers from septic rats exhibited both a ...

A rat epididymal protein (MW 32000) was isolated and purified from the rat caudal epididymal fluid. Mono-specific antiserum against this protein was raised in rabbits, purified and labelled with 125I. The labelled IgG was infused intravenously into anaesthetized male rats, and the transfer of the labelled IgG across the luminally ...

The proportion of total hepatic energy utilized for bile formation and transport of taurocholate (TC) and conjugated sulfobromophthalein (cBSP) has not been defined previously. To study this question we have measured changes in oxygen consumption by the isolated perfused rat liver and freshly isolated hepatocytes occurring in response to TC ...

An attempt to evaluate the role of the liver in extrarenal erythropoietin production was made by measuring the content of erythropoietin in homogenates and perfusates from hypoxic rat livers. Extracts from livers from nephric or anephric animals rendered both anemic and hypoxic showed no detectable erythropoietin despite the fact that ...

Two min of intraluminal perfusion of the rat proximal tubules with autologous serum induced marked ultrastructural alterations including extensive cytoplasmic vesiculation due to swelling of rough endoplasmic reticulum cisternae and occasional extrusion of nuclei and cytoplasm into the lumen. Within 4 min pronounced vesiculation of mitochondria was observed. These findings ...

The permeability of the glomerular capillary wall to neutral macromolecules was studied in isolated perfused rat kidneys. Pluronic F108 (BASF, Wyandotte, MI, USA), a polyoxyethylene-polyoxypropylene block copolymer of mol weight approximately 14,000, was used as plasma expander. Pore theory was applied to the fractional clearances of Pluronic F108 and dextran ...

Synthetic (+/-) 1-O-octadecyl-2-acetyl-glyceryl-3-phosphorylcholine (octadecyl-AGPC) in microgram/kg doses given intravenously effectively and potently lowered mean arterial blood pressure in conscious and anesthetized normotensive rats. The hypotensive activity was much more pronounced in the anesthetized rat than in the conscious rat. The hypotension was associated with a significant elevation in plasma renin ...

14C-Benzidine (BZ) was added to the recirculating perfusate of the isolated perfused rat liver. The system was monitored at timed intervals for the disappearance of BZ and the appearance of metabolites. BZ was extensively metabolized by this system and after 2 hr of perfusion greater than 95% of the administered ...

Apolipoprotein B (apoB) is composed of metabolically distinct fractions of higher molecular weight (apoBh) and lower molecular weight (apoBl). When 125I-labeled very low density lipoprotein (VLDL) prepared from recirculating liver perfusates was injected into rats, labeled apoBl was preferentially removed from the plasma and apoBh entered low density lipoprotein (LDL). ...

A procedure is described to convert rates of (14)CO(2) production into rates of mitochondrial acetyl-CoA production from a (14)C-labelled substrate. The principle is illustrated in perfused rat liver and kidney by the differential yield of (14)CO(2) from 4-methyl-2-oxo[1-(14)C]valerate and 4-methyl-2-oxo[2-(14)C]valerate.

Following isolated liver perfusion with different cytotoxins - 5-fluorouracil (5-FU), methotrexate (MTX), dacarbazine (DTIC) cis-platinum (cis-PT) - liver tissue of dogs was examined with the electron microscope (a) directly after the perfusion and (b) after a survival time of 4 weeks (5-FU and DTIC). Acute disintegration of the granular endoplasmic ...

1. An emulsion of perfluorodecalin was used as a substitute for erythrocytes in a synthetic medium in the perfusion of isolated rat livers. 2. The efficiency of this oxygen carrier in maintaining liver viability and function was compared with an erythrocyte-containing medium. 3. Activities of the microsomal mono-oxygenase system, secretion ...

The rates of metabolism of 7-ethoxycoumarin and subsequent conjugation of 7-hydroxycoumarin were studied in perfused livers from hypophysectomized or sham-operated control rats. Rates of 7-ethoxycoumarin O-deethylation were higher both in perfused livers and microsomes from hypophysectomized compared to sham-operated controls. However, conjugation of 7-hydroxycoumarin formed from 7-ethoxycoumarin was markedly decreased ...

Perfusion of rat jejunal segments in vivo with an isotonic, HCO3-free SO4-Ringer solution resulted in low rates of net sodium (JNanet) and water absorption. When the perfusion fluid was changed to one containing 25 mM Na2SO3, JNanet increased from 4.7 +/- 1.2 to 11.6 +/- 1.5 (SE) mumol X cm-1 ...

Accumulation of Tyr-D-Ala-Gly (TAG) in choroid plexus was studied with ventriculocisternal perfusion of anesthetized rats. The choroid plexus of the lateral ventricles and the fourth ventricle accumulated TAG against a concentration gradient with regards to cerebrospinal fluid (CSF) but not plasma. This accumulation was inhibited by some metabolic inhibitors and ...

(14)CO(2) production by perfused rat livers was simulated by infusing NaH(14)CO(3) into the perfusate. Recovery of label as (14)CO(2) gas + perfusate bicarbonate was 45-85%. Rates of (14)CO(2) exchange in the liver are 3-70 times greater than net rates of CO(2) production. Therefore (14)CO(2) reincorporation can lead to significant underestimations ...

Human and bovine glomerular basement membranes (GBM) were previously shown to be a three-dimensional molecular sieve composed of pores and strands by negative staining and electron microscopy. In this study, rat GBM were isolated under several different conditions to rule out morphological changes due to isolation procedures. Rat GBM isolated ...

Plasma catecholamines and vascular response to noradrenaline were studied in phosphate depleted rats. Phosphate depletion was induced in rats by dietary phosphorus deprivation for 6 weeks. Basal plasma concentrations of noradrenaline, adrenaline and dopamine were elevated in phosphate depleted rats compared to pairfed control rats. After exposure to cold (4 ...

This study evaluates the role of neutrophil granulocytes in mediating acute phase stimulation of fibrinogen synthesis. Turpentine was administered to neutropenic and non-neutropenic rats and fibrinogen synthetic rates measured in an isolated liver perfusion system. Using the (14C) carbonate technique for the measurement of the absolute synthetic rates of liver ...

Harmol is conjugated by glucuronidation and sulfation when it is given to the rat in vivo. In the once-through perfused rat liver preparation glucuronidation of harmol shows kinetic aberrances [Pang et al., J. Pharmac. exp. Ther. 219, 134 (1981)]. In order to further delineate the mechanism behind this, sulfation was ...

Isolated rats livers were perfused with Krebs-Ringer-Bicarbonate (KRB) and different doses of insulin or glucagon and with insulin plus glucagon. The isolated liver of fasted rats and of rats treated with streptozotocin were perfused with (KRB). The glomerulopressin activity of the ultrafiltrate of the liver perfusates were assayed in the ...

The correspondence of conjugative metabolism rates in vivo and in vitro was studied in rat using p-nitrophenol (PNP) as a model compound. In PNP-glucuronide conjugation, the hepatic intrinsic clearance calculated from Km and Vmax obtained in the isolated liver cells was approximately three times larger than that calculated by the ...

We developed a simple and inexpensive method of perfusing small specimens of human liver in vitro that maintains short-term tissue viability as judged by protein transport function and morphological features. The technique allows investigation of liver function at the cellular level in normal specimens and those with hepatobiliary disease. Electron ...

The effects of the diuretic agents, MK-196 (6,7-dichloro-2-methyl-1-oxo-2-phenyl-5-indanyloxy acetic acid) and furosemide on function of medullary thick ascending limb (tALH) isolated from the rat kidney were studied. tALH were dissected from whole kidneys of male Sprague-Dawley rats which were first perfused in vitro in a recirculating system for 10 to ...

Livers of pregnant or nonpregnant rats were perfused, and incorporation of 14C-acetate into lipids was studied. Total lipids were extracted from samples of perfusion medium, taken at the entrance and exit from the liver, at different time intervals, and from the liver homogenates at the end of the experiment. Time-course ...

The major site(s) of synthesis of plasma fibronectin is unknown. Using the isolated perfused rat liver and anti-rat fibronectin antiserum, we have measured net hepatic synthesis of fibronectin during 10-hr perfusion periods. We calculated the circulating plasma fibronectin pool of a 195-g rat with body surface area of 300 sq ...

Models to explain the pathophysiology of protoporphyria have been based on fluxes of protoporphyrin between plasma and liver for which no quantitative data exist. The present studies employed isolated, in situ, recirculating and nonrecirculating rat liver perfusions to define the kinetics of hepatic uptake and biliary secretion of protoporphyrin. Livers ...

The abdominal aorta of the rat was isolated and perfused. Pulsations were found to be a prerequisite for prostacyclin production in the isolated aorta. In the pulsatingly perfused aorta, the prostacyclin production decreases rapidly during the first 30 min of perfusion and very slowly between 30 and 120 min. The ...

A simplified sulphide/silver technique for visualizing transitional metals in rat brain is described. It consists of: (1) sulphide perfusion before formaldehyde perfusion, (2) routine paraffin embedding and sectioning, and (3) silver staining with physical developer. This method is compatible with formaldehyde fixation, eliminates the need for post-fixation in Carnoy's solution ...

A rapid and inexpensive method has been developed to estimate rates of benzo(a)pyrene phenol production by perfused rat liver. This method is based on the measurement of benzo(a)pyrene phenols utilizing a simple fluorometric procedure. Within 2 to 3 min after infusion of benzo(a)pyrene bound to serum albumin, phenols are excreted ...

1. Renal handling of pig- and rat-insulin was studied in the isolated perfused rat kidney. 2. Metabolic clearance rates of both pig- and rat-insulin exceeded GFR. 3. Peritubular uptake of pig-insulin accounted for 13% of rat-insulin for 31% of the total metabolic clearance. 4. The nonfiltering kidney does not remove ...

An investigation has been made into whether charcoal hemoperfusion stimulates a hyperplastic response in the liver of the normal rat. Animals underwent hemoperfusion over Norit RBX1 (Strathclyde, Glasgow, U.K.) charcoal granules using a technique which allowed perfusion in the unrestrained and conscious state. Controls consisted of animals subjected to perfusion ...

An investigation has been made into the effects of repeated charcoal hemoperfusion in the rat on liver pathophysiology. Animals underwent hemoperfusion over Norit RBX1 charcoal using a technique which allowed perfusion in the unrestrained and conscious state, thus minimizing any possible effects from stress and eliminating the necessity of repeated ...

A constant-flow, nonrecirculating system was used to study the extraction efficiency of colloidal carbon in the perfused liver of rats and rabbits. In both species, a diminution in perfusate flow produced an increased extraction efficiency. The extraction efficiency also increased with a decrease in the carbon concentration of the perfusate. ...

Isolated rat liver perfusates contain a substance which inhibits 3H-thymidine uptake by phytohemagglutinin-stimulated human peripheral blood lymphocytes in a dose-dependent, noncytotoxic fashion. Suppression is not due to interference of lymphocyte-phytohemagglutinin interaction or dilution of the thymidine pool. Complete inhibition of thymidine uptake is achieved with less than 1.0 microgram of ...

The isolated rat liver was used to investigate the role of the liver in the regulation of circulating uridine concentrations. A synthetic blood substitute (Fluosol-43) was utilized as an alternative oxygen-carrying perfusion medium to a simplified blood preparation and produced no apparent hepatotoxicity within the perfusion period. The isolated rat ...

A push-pull perfusion technique was used to sample third ventricular cerebrospinal fluid (CSF) in the conscious rat. Ventricular perfusate contained significant quantities of vasopressin and oxytocin, 13.1 and 4.5 pg/ml, respectively. Vasopressin and oxytocin levels were stable over a 3 h perfusion period. High sodium artificial CSF elicited a 4-5-fold ...

The release of somatomedin from perfused livers of normal and hypophysectomized (hypox) rats has been studied. Somatomedin was determined by the radioreceptor assay for somatomedin A. The release of somatomedin in the perfusates of normal livers was observed during the initial 30 minutes and maintained during the second and third ...

1. Isolated livers from fed male rats were perfused for 2 h with T4 (L-thyroxine), T3 (L-3,3',5-tri-iodothyronine) or rT3 (L-3,3',5'-tri-iodothyronine) at different pH values (7.1--7.6) in a fully synthetic medium, whereby normal metabolic functions were maintained without addition of rat blood constituents or albumin. 2. T3 output into the medium ...

Mutagenic effect of styrene and styrene-7,8-oxide was studied with the isolated perfused rat liver as metabolizing system and Chinese hamster V79 cells as genetic target cells. Styrene-7,8-oxide which is mutagenic per se was rapidly metabolized by the perfused rat liver. Thus no mutagenic effect was detected neither in the perfusion ...