摘要:

Acute disruption of the renal blood supply has been shown by several workers to alter renal cortical metabolic functions and some transport processes. The present study was designed to examine acute ischemic effects on transport functions for both organic and inorganic substances. Acute clamping of the renal artery, renal vein, and ureter for 45 min produces a reversible disruption of tissue electrolyte and water balance. Longer occlusion appeared to produce irreversible effects. α‐Aminoisobutyrate (AIB) and lactate‐stlmulatedp‐aminohippurate (PAH) transport were altered selectively by the 45‐min occlusion. A longer occlusion period also depressed base‐line PAH and tetraethylammonium (TEA) transport. Some of the depression of the organic compound transport functions are reversible. Renal cortical oxygen consumption measuredin vitrowas affected minimally.

ISSN:0098-4108    

DOI:10.1080/15287397609529412

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

[14C]Methyl mercury was administered by three different routes: intravascular (iv) injection, ingest ion, and absorption from the ambient water. After iv administration (0.1 mg/kg) [14C]methyl mercury was rapidly removed from the plasma, followed by slow loss from the hepatopancreas and a strikingly persistent increase in the amount of radioactivity in the tail muscle. Most (80–90%) of the radioactivity in the hepatopancreas was shown by TLC methods to be the parent compound, and approximately 10% of this persisted for 6 days after injection. The half‐life in this organ was found to be 21 days. One month after iv treatment with methyl mercury, the only organs that contained more than 0.1 ppm of this xenobiotic were egg masses, male gonads, heart, brain, intestine, and tail muscle. The half‐lives for disappearance from sexual organs were greater than 1 month. After ingestion of [14C]methyl mercury (0.1 mg/kg) in food the hepatopancreas contained most of the administered dose at 6 days (68%), while the stomach (10%), tail muscle (8%), and carcass (15%) contained less. A unique distribution pattern emerged 6 days after exposure to [14C]methyl mercury‐containing ambient water (0.1 ppm). Tha tail muscle contained most (50%) of the absorbed dose, whereas the hepatopancreas and carcass contained only 23 and 10%, respectively. In view of the small molecular size and high lipid solubility of methyl mercury and the lipophilic properties of the chitin‐protein exoskeleton of the lobster, it is likely that significant uptake directly from the water as well as storage of absorbed methyl mercury occurred in the tail region. Residue analysis on untreated lobsters indicated that the egg masses contained the largest amount of methyl mercury (0.1 ppm). The hepatopancreas and carcass (muscle) levels were <0.05 ppm.

ISSN:0098-4108    

DOI:10.1080/15287397609529413

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Change of glycine cleavage activity in liver mitochondria of lead‐intoxicated rats was studied in this paper. The following results were obtained: (1) The activity in hepatic mitochondria of rats was decreased by a single administration of lead (4 mg/100 g body weight); (2) in vitro the activity in the normal rat liver mitochondria was markedly inhibited by addition of lead acetate (4 mM).

ISSN:0098-4108    

DOI:10.1080/15287397609529414

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Beta‐hydroxyproplonitrile (β‐HPN) was incorporated in the drinking water of rats in order to define the toxicological effects associated with repeated daily exposure to this compound. Parameters evaluated were appearance and demeanor, mortality, body weight, food consumption, water consumption, hematology, terminal organ weights and organ to body weight ratio, and gross and microscopic pathology of tissues. No untoward effects were associated with the ingestion of β‐HPN at the dose levels utilized.

ISSN:0098-4108    

DOI:10.1080/15287397609529415

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The significance of bile as an excretory route for cadmium (Cd) was studied in anesthetized, bile‐duct‐cannulated Sprague‐Dawley rats during a 6‐hr collection period. Observations were made on bile flow rates, the concentrations of Cd in bile following dietary and parenteral Cd exposure, and the influences of zinc (Zn), selenium (Se), and Cd pretreatments upon the biliary excretion of subsequently admilnistered Cd. The bile flow rates ranged between 1.96 and 2.89 mglg rat‐hr (22 ± 3 ppb Cd) for normal rats and between 2.68 and 4.09 mglg rat‐hr (58 ± 6 ppb Cd) for rats fed 100 ppm Cd. Less than 0.1% of the Cd administered subcutaneously at rates ranging from 0.25 to 40 mg/kg rat could be accounted for in bile collected during the 5‐hr period following the parenteral Cd injections. Subcutaneous administration of 8 mg Zn/kg rat or 0.5 mg Cd/kg rat on days 1 and 6, respectively, before the postcannulation administration of 1 mg Cd/kg rat caused a significant reduction in the biliary excretion of Cd during the bile collection period. Administering 2 mg Se/kg rat 3 days prior to the postcannulation administration of 1 mg Cd/kg rat caused a significant increase in the biliary excretion of Cd during the bile collection period. The biochemical bases for these observations are believed associated with the type of metal‐binding protein induced by the respective pretreatments.

ISSN:0098-4108    

DOI:10.1080/15287397609529416

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Intoxication with 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) results in marked increases in cellular smooth endoplasmic reticulum content and microsomal drug metabolizing enzyme activity in kidney cortex. Therefore, it was of interest to determine the effect of TCDD on several proximal tubular functions. Adult rats were treated with 10, 25, and 50 μg/kg, intraperitoneally, or 1 and 5 μg, intragastrically, TCDD. Neither intragastric dose of TCDD had a significant effect on the ability of renal cortical slices to accumulatep‐aminohippuric acid (PAH) 7 days after treatment. Similarly, 10 μg/kg TCDD 3 or 7 days after treatment did not affect PAH accumulation.N‐methylnicotinamide (NMN) accumulation was slightly decreased following this treatment. At 25 μg/kg, TCDD decreased the capacity of renal tissues to transport both PAH and NMN 7 days after exposure. Accumulation of 2‐deoxyglucose was unaffected by TCDD. The increase in ammoniagenesis and gluconeo‐genesis observed in acidotic states was not significantly different in animals that had been treated with 25 μg/kg TCDD 7 days before experimentation. Glomerular filtration rate and effective renal plasma flow were decreased in rats after 25 or 50 μg/kg TCDD. Volume expansion did not alter this relationship. Fractional sodium excretion was less than 1% in both control and TCDD‐treated animals. With volume expansion sodium excretion increased to approximately 5% and was not different for control and TCDD‐treated animals. The effect of TCDD on renal function is, therefore, most likely a result of general toxicosis rather than specific functional lesions.

ISSN:0098-4108    

DOI:10.1080/15287397609529417

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The effects of piperonyl butoxide (PB) on the metabolism and toxicity of dimethylnitrosamine (DMN) in Swiss mice were determined. PB, at doses of 10 and 20 mg/kg, inhibited DMN demethylase 45 min after treatment by 18 and 37%. These inhibitory effects were marked 0.5 hr after PB (640 mg/kg) treatment and reached maximal effects at 2 hr when there was 55% inhibition of enzyme activity. The inhibition by PB continued for 24 hr where enzyme activity was suppressed by 35%. At 48 hr after treatment there was stimulation of enzyme activity. Enzyme kinetic determinations showed no change in Kmbut Vmaxdecreased from 129 to 49 μmol CH2O/min‐g liver. PB (640 mg/kg) inhibited DMN (500 mg/kg; im) mutagenicity in the host‐mediated assay, decreasing the mutant frequency by 42%. Paradoxically, PB (640 mg/kg) had no effect on the alkylation of nucleic acids or proteins in mouse liver, kidney, lung, or spleen. In addition, pretreatment with PB (640 mg/kg) had no effect on the LD50of DMN.

ISSN:0098-4108    

DOI:10.1080/15287397609529418

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Exposure levels of the principal carcinogenic and potential carcinogenic metal and metalloid pollutants in the environment (e.g., arsenic, beryllium, chromium, nickel, cadmium, and lead) are primarily reviewed with emphasis on their environmental sources both natural and manmade. There is a general paucity of definitive information concerning aspects of material balance and chemical transformations of these elements in various chemical forms in the environment, primarily the atmosphere. Estimates of both exposure levels and risk to populations other than industrial workers of the above metals have been in most instances quite difficult to obtain and generally speculative.

ISSN:0098-4108    

DOI:10.1080/15287397609529419

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Methods for monitoring trace levels of 4‐aminobiphenyl, 2‐naphthylamine, and their hydrochloride salts in waste water, microbiological growth media, potable water, human urine, and mouse blood utilizing spectrophotofluorometry (SPF) are described. The salient elements of the methods are extraction of the residues as the free amine with benzene, rapid cleanup on an alumina column, and quantification of the free amine in methanol via SPF. Potable water solutions of the salts are diluted with 0.01 N aqueous HCL and quantified directly by SPF. Ancillary analytical information concerning gas chromatography of the free amines, partitioning properties of the compounds between solvent pairs, their solubility and stability in water, and thin‐layer chromatographic data is presented. The compositions of various admixtures of 1‐ and 2‐naphthylamine or their salts were determined by using SPF with calculations based on simultaneous equations.

ISSN:0098-4108    

DOI:10.1080/15287397609529420

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Water deprivation for 48 hr with its accompanying decrease in food intake significantly lowered the in vitro rate of hexobarbital metabolism by hepatic microsomes isolated from male rats. Pair‐fed rats allowed waterad libitumhad a significantly lower level of hexobarbital metabolism than those deprived of water. Rats starved for 24 hr with or without water also had levels of hexobarbital metabolism significantly lower than their controls; with those animals allowed water ad libitum, the level was significantly lower than for those deprived of water.In vivohexobarbital “sleeping time” experiments were in general agreement with these results. The in vitro metabolism of aniline was increased in both male and female rats following 24 hr starvation and in female rats (but not males) the effect was greater when water was allowed than when deprived. The differences between hydrated and dehydrated animals were not attributable to reduction in concentration of microsomal protein or the water content of liver. It is concluded that water consumption accentuates the effect of food deprivation on hepatic microsomal metabolism.

ISSN:0098-4108    

DOI:10.1080/15287397609529421

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor