Effect of chlorophyllin on mercuric chloride-induced clastogenicity in mice.

The effect of chlorophyllin (1.5 mg/kg body weight) on the clastogenicity of mercuric chloride (HgCl2) was studied in vivo in mouse bone marrow cells. HgCl2 (3.0, 6.0 and 12.0 mg/kg body weight) administered by gavage induced chromosomal aberrations at frequencies directly proportional to the dose. Chlorophyllin was not clastogenic, and significantly reduced the mitotic index when given alone. Chlorophyllin administered simultaneously with HgCl2 significantly reduced the frequencies of chromosomal aberrations in a dose-dependent manner. When given simultaneously with the lowest HgCl2 concentration tested (3.0 mg/kg body weight), chlorophyllin provided total protection. A lower degree of protection was given by chlorophyllin administered 2 hr before HgCl2. The data demonstrate the potential of green plant components to modify the genotoxic activity of HgCl2 when administered orally.     

Kappa opioid-induced diuresis in female vs. male rats

Kappa opioid agonists may produce dissimilar discriminative and analgesic effects in female vs. male subjects. The present study was conducted to determine whether a prototypic physiological effect of kappa agonists--diuresis--also differs between the sexes. When data were not corrected for individual differences in body weight, the kappa agonists U69,593 (0.03-3.0 mg/kg), U50,488 (0.3-10 mg/kg), (-)-bremazocine (0.001-0.1 mg/kg) and (-)-pentazocine (1-10 mg/kg), as well as a nonopioid diuretic, furosemide (1-10 mg/kg) produced significantly greater diuresis in normally hydrated, age-matched males than females; however, there was no sex difference in the diuretic effect of butorphanol (0.3-3.0 mg/kg), or in the antidiuretic effect of the mu agonist morphine (1.0-5.6 mg/kg, in water-loaded rats). In contrast, when data were corrected for individual difference in body weight, U69,593, U50,488, (-)-bremazocine, (-)-pentazocine, and furosemide produced nearly equivalent diuresis/kg in females and males, whereas butorphanol produced slightly greater diuresis/kg, and morphine produced significantly less antidiuresis/kg, in females than males. U69,593-induced diuresis was highly similar in males and females of similar body weight (i.e., different ages). U69,593 effects were dose-dependently antagonized by the kappa antagonist nor-binaltorphimine in both sexes, indicating a common, kappa receptor-mediated mechanism of action. (-)-Bremazocine was slightly more potent in suppressing vasopressin in 24-h water-deprived males than females. These results suggest that the greater diuretic effects of kappa receptor-selective opioid agonists in male rats are primarily due to males' larger body size (greater body water) relative to age-matched females, but may also be attributed to slightly greater vasopressin suppression in males.     

A chronic toxicity study of josamycin in F344 rats.

The chronic toxicity of josamycin was examined in Fischer 344 (F344) rats. Groups of 10 males and 10 females were given the test compound in the diet at concentrations of 0 (control), 0.02, 0.1, 0.5 or 2.5% for 52 weeks. Daily intake of josamycin was 0, 10, 50, 260 and 1310 mg/kg body weight in males and 0, 10, 60, 290 and 1460 mg/kg body weight in females, respectively. Body weight gain was significantly (P<0.05) reduced in the male 2.5% group but no noticeable changes were found in food intake. In hematological examination, the platelet count was significantly (P<0.01) lower in the male groups given 0.02% or more of josamycin and in the 2.5% female group as compared with the control group values in a dose-dependent manner. In serum biochemical examination, blood urea nitrogen was significantly (P<0.05 and P<0.01, respectively) higher in males given 0.5 and 2.5% and total bilirubin was significantly (P<0.05) higher in females receiving 2.5% as compared with those of the control group. No death occurred at any dose levels during the dosing period. At necropsy, with the exception of cecal enlargement in the groups given more than 0.1% josamysin and a significant (P<0.01) increase in the relative liver weight of females in the 2.5% group, no particular findings related to the administration were observed. Histopathologically, the incidence and severity of liver bile duct proliferation in female 2.5% group were significantly (P<0.01) greater than those of the control group. Other histological changes found in the treated and control groups were similar to the spontaneous lesions in this strain of rats in terms of the incidence and severity. Interestingly, the josamycin treatment reduced the development of altered liver cell foci in females in a dose-dependent manner. Thus, it is concluded that, under the present experimental conditions, josamycin induces bile duct proliferation in female F344 rats at a high dose of 1460 mg/kg body weight. Based on the decrease of platelet count found in males given 10 mg/kg body weight or more, the no-observed-adverse-effect level (NOAEL) was estimated to be less than 10 mg/kg body weight.     

Six-week treatment with Ukrain in rabbits. Part II: Serum levels of gonadal hormones

The effect of 6-week treatment with Ukrain at doses of 0.3, 1.5, and 3.0 mg/kg i.v. on the serum levels of steroid hormones, i.e., estradiol, testosterone, and progesterone, was studied in rabbits of both sexes. It is demonstrated that Ukrain treatment exerts minor changes in serum hormone levels. The level of estradiol was increased in the serum of male rabbits following Ukrain treatment only at the dose of 1.5 mg/kg i.v. Similarly, the estradiol serum level was increased after Ukrain given at 1.5 mg/kg i.v. in female rabbits. In male rabbits Ukrain application at 0.3 mg/kg i.v. increased the serum testosterone level. Serum testosterone levels were not altered following Ukrain administration up to 3.0 mg/kg i.v. in female rabbits. Ukrain raised the serum progesterone levels in male rabbits at the doses of 0.3 and 3.0 mg/kg i.v. in females, only the highest dose of Ukrain produced a significant increase of serum progesterone.     

Suppression of uterine decidualization correlated with reduction in serum progesterone levels as a cause of preimplantation embryonic loss induced by diphenyltin in rats

In our previous study, diphenyltin dichloride (DPTCl) at 16.5 mg/kg and higher on days 0-3 of pregnancy was found to induce preimplantation embryonic loss in rats. In the present study, the effects of DPTCl on uterine decidualization in pseudopregnant rats, effects of ovarian hormones on uterine decidualization in ovariectomized rats, and effects of progesterone on the DPTCl-induced preimplantation embryonic loss in pregnant rats were determined. Female rats were given DPTCl by gastric intubation at 4.1, 8.3, 16.5, or 24.8 mg/kg on days 0-3 of pseudopregnancy and the decidual cell response was induced on day 4 of pseudopregnancy. The uterine weight on day 9 of pseudopregnancy served as an index of uterine decidualization. A significant decrease in uterine weight, which indicates suppression of uterine decidualization, was detected at 16.5 and 24.8 mg/kg. Ovarian weight and number of corpora lutea in the DPTCl-treated groups were comparable to the controls. A significant decrease in the serum progesterone levels was found at 16.5 and 24.8 mg/kg in pseudopregnant rats. The hormonal regimen consisting of progesterone and estrone-supported decidual development in ovariectomized rats given DPTCl. Pregnancy rate and number of implantations were significantly lower in the intact mated groups given DPTCl at 16.5 and 24.8 mg/kg on days 0-3 of pregnancy than in the control group and significantly higher in the groups given DPTCl plus progesterone than in the groups given DPTCl alone. These results show that reduction in serum progesterone levels is correlated with suppression of uterine decidualization and progesterone protects against preimplantation embryonic loss induced by DPTCl.     

Effects of subcutaneous administration of daidzein on blastocyst implantation in rats.

The study was conducted to investigate the effects of phytoestrogen daidzein on blastocyst implantation in rats. Following successful mating, female rats were given daidzein by subcutaneous administration at the dose of 0 (vehicle control, n=15), 50 mg/kg body weight (n=15) and 150 mg/kg body weight (n=15) daily on day 1-7 of pregnancy and were sacrificed on day 8 of gestation. The results revealed that high-dose treatment (150 mg/kg body weight) significantly diminished the rate of blastocyst implantation and serum levels of gonadotropin-releasing hormone (GnRH), progesterone, and gonadotropins (FSH and LH), meanwhile the serum level of beta endorphin increased significantly. These effects were not observed in the low-dose treatment group (50 mg/kg body weight). The results of this study suggested that the anti-implantation effects of daidzein are probably caused by the interference of the hypothalamus-pituitary-gonadal axis which is involved in the implantation process.     

IN VIVO EFFECTS OF BISPHENOL A ON THE POLECAT ( MUSTELA PUTORIUS )

Bisphenol A (BPA), an environmental estrogen derived from the plastic industry, was given orally via incorporation into the food of 30 male and female polecats at 3 different doses (10, 50, or 250 mg/kg body weight/day) for 2 wk with 10 animals acting as controls. Several hormone levels in the plasma were determined as well as the activities of the phase I and II biotransformation enzymes 7-ethoxyresorufin O-deethylase (EROD), cytosolic glutathione S-transferase (GST), and UDP-glucuronosyltransferase (UDPGT). BPA did not cause any macroscopic effects on body mass or the health of the animals. UDPGT and GST activities increased significantly in direct correlation with increasing BPA exposure in females and UDPGT increased in a dose-related manner in males. There was no change in the plasma T4 and testosterone concentrations of the males with increasing BPA exposure. Discriminant analysis indicated that the group receiving 10 mg BPA/kg body weight/d was not different from the control group but the groups receiving 50 and 250 mg/kg body weight/d were different from the control group. This suggests physiological changes in the groups receiving 50 or 250 mg BPA/kg body weight/d.     

In vivo effects of bisphenol A on the polecat (mustela putorius)

Bisphenol A (BPA), an environmental estrogen derived from the plastic industry, was given orally via incorporation into the food of 30 male and female polecats at 3 different doses (10, 50, or 250 mg/kg body weight/day) for 2 wk with 10 animals acting as controls. Several hormone levels in the plasma were determined as well as the activities of the phase I and II biotransformation enzymes 7-ethoxyresorufin O-deethylase (EROD), cytosolic glutathione S-transferase (GST), and UDP-glucuronosyltransferase (UDPGT). BPA did not cause any macroscopic effects on body mass or the health of the animals. UDPGT and GST activities increased significantly in direct correlation with increasing BPA exposure in females and UDPGT increased in a dose-related manner in males. There was no change in the plasma T4 and testosterone concentrations of the males with increasing BPA exposure. Discriminant analysis indicated that the group receiving 10 mg BPA/kg body weight/d was not different from the control group but the groups receiving 50 and 250 mg/kg body weight/d were different from the control group. This suggests physiological changes in the groups receiving 50 or 250 mg BPA/kg body weight/d.     

Diesel exhaust affects the abnormal delivery in pregnant mice and the growth of their young

To clarify the toxic effects of diesel exhaust (DE) on delivery in mice and on growth of young, C57Bl-strain females were exposed to 0.3, 1.0, or 3.0 mg diesel exhaust particles (DEP)/m3 or filtered clean air (control) for 4 mo (12 h/day, 7 days/wk). After exposure, some females from each group were examined by necropsy, and the remainders were mated with unexposed males. Estrous females for necropsy who had been exposed to 1.0 mg DEP/m3 had significantly lower uterine weights than the control estrous females. In the mated females, 9.1, 10.0, or 25.0% (0.3, 1.0, or 3.0 mg DEP/m3 of the pregnancies resulted in abnormal deliveries (abortion and unable delivery), but this was not significant. The rate of good nest construction by delivered females exposed to 3.0 mg DEP/m3 was significantly lower. Young were weighed at 11, 14, and 21 days, and weekly from wk 4 to 9 after birth. Body weights of male young of dams exposed to 1.0 or 3.0 mg DEP/m3 were significantly lower at 6 and 8 wk of age. Body weights of female young of dams exposed to 1.0 or 3.0 mg DEP/m3 were also significantly lower at 6, 8, and 9 wk. Vaginal orifices of young female mice whose dams were exposed to 0.3 and 1.0 mg DEP/m3 opened significantly earlier. The young were killed at 30 or 70 days during deep anesthesia, and their body weights, organ weights, and body lengths were measured. Anogenital distance (AGD) of 30-day-old males whose dams were exposed to 0.3 mg DEP/m3 was significantly shorter than that of the controls. Weights of thymus and ovary in 30-day-old females whose dams were exposed to 3.0 mg DEP/m3 were significantly lower. In 70-day-old males of dams exposed to 3.0 mg DEP/m3, body weights were significantly lower and AGD was significantly shorter. Weights of adrenals, testes, and seminal vesicles in 70-day-old males with dams exposed to 1.0 mg DEP/m3 were significantly lower. In 70-day-old females with dams exposed to DE, body weights in the 3.0-mg DEP/m3 group were significantly lower, and weights of adrenals, liver, and thymus in the 1.0-mg DEP/m3 group were significantly lower. Thymus weights in 70-day-old females with dams exposed to 0.3 mg DEP/m3 were significantly lower. Crown-rump length (CR) in 70-day-old females with dams exposed to 1.0 or 3.0 mg DEP/m3 was significantly shorter. These results show that toxic substances in DE might cause abnormal delivery in mice, and that exposed females affected the growth and sexual maturation of their young.     

Short term toxicity study in rats dosed with isoeugenol benzyl ether

Isoeugenol benzyl ether was given to rats by gavage for 28 days at 0, 60, 120, and 240 mg/kg body weight/day. For both sexes at the highest dose and females at the intermediate dose statistically significantly decreased values were found for body weight, blood glucose (also for males at intermediate dose), blood urea and relative liver weights. No dose-related histopathological changes were seen in any organs. The no effect level was 60 mg/kg body weight/day.     

The pharmacokinetics and metabolism of pentachlorophenol in rats

The pharmacokinetic profile of pentachlorophenol (PCP) was determined in male and female rats to assist in the assessment of its toxic hazard. Metabolism, excretion, and blood plasma concentrations as a function of time were determined for rats given 10 or 100 mg of [¹⁴C]PCP/kg. Elimination of PCP from the body was by catabolism to tetrachlorohydroquinone, by excretion of unchanged PCP and its glucuronide conjugate in the urine, and by excretion of PCP or its metabolites into the bile. The metabolites of PCP were rapidly excreted via the urine and were not retained in the body. The dynamics for the overall elimination of radioactivity from the body was biphasic in males and females given 10 mg/kg and in males given 100 mg/kg. For females given 100 mg/kg, it was monophasic, suggesting a dose-dependent fate. The rapid phase of elimination had half-lives of 17 and 13 hr for males and females given 10 mg/kg and 13 hr for males given 100 mg/kg. Over 90% of the dose was eliminated during the rapid phase. For females given 100 mg/kg, the monophasic elimination had a half-life of 27 hr. Analysis of the radioactivity in selected tissues from males and females given 10 mg/kg revealed the highest concentrations in the liver and kidneys and the lowest in the brain and fat. In females plasma concentrations of PCP were consistently higher than in males. About 99% of the PCP in plasma was bound to protein, which probably was responsible for low tissue-to-plasma ratios and a low renal clearance rate.     

Lower plasma levels of haloperidol in smoking than in nonsmoking schizophrenic patients.

The impact of smoking on plasma haloperidol (HAL) concentrations was investigated in 66 Japanese male schizophrenic inpatients treated orally with HAL. The subjects consisted of 22 nonsmokers and 44 smokers each smoking ten cigarettes per day. Plasma concentrations of HAL were determined by an enzyme immunoassay method. There were significant positive correlations between the plasma HAL concentration and the daily dose of HAL per kg body weight (Y = 58.1X-0.01 (r = 0.86)). Smokers had significantly lower HAL concentrations per daily dose of HAL/kg body weight than nonsmokers (smokers vs. nonsmokers = 54.3+/-16.6 vs. 70.6+/-23.2 ng/mL/mg/kg). In doses less than 0.2 mg/kg of HAL, smokers showed significantly lower HAL concentrations per daily dose of HAL/kg body weight than nonsmokers (smokers vs. nonsmokers = 55.1+/-14.4 vs. 79.5+/-27.1 ng/mL/mg/kg), whereas no significant difference in HAL concentrations per daily dose of HAL/kg body weight was observed between smokers and nonsmokers when treated with more than 0.2 mg/kg (smokers vs. nonsmokers = 52.9+/-20.7 vs. 60.0+/-11.1 ng/mL/mg/kg). Our results indicate that smoking may induce the enzyme(s) metabolizing HAL, which results in lower plasma HAL concentrations in smokers than in nonsmokers, particularly at low doses of HAL.     

Effects of methylphenidate on schedule dependent and schedule induced behavior.

The effects of methylphenidate, 1.5, 3.0, 6.0 and 12.0 mg/kg, on lever pressing, schedule induced licking, and drinking were studied. The generator schedule was a fixed interval 1 min food reinforcement schedule. The effects were assessed when animals were reduced to 80% body weight by partial food deprivation and when allowed to recover body weight under conditions of ad lib eating. Results indicate that under body weight conditions methylphenidate significantly decreases schedule induced licking and drinking but does not affect lever pressing.     

Ukrain: acute toxicity after intravenous, intramuscular and oral administration in rats

The acute toxicity of Ukrain (1 g/30 ml) was determined after a single intravenous, intramuscular or oral administration in rats, performed in accordance with Good Laboratory Practice and the relevant European Community directive. Groups of five (male and/or female) Him:OFA rats were treated once with the following doses: intravenous route: 1.0 ml/kg (males and females), 1.7 ml/kg (males and females) and 3.0 ml/kg (females); intramuscular route: 5.0 ml/kg (males and females); oral route: 15.0 ml/kg (females), 27.0 ml/kg (males and females) and 50 ml/kg (females). The animals were kept for up to 14 days afterwards while clinical observations and body weight determinations were made and were then necropsied. An intravenous injection of Ukrain (1 g/30 ml) induced immediate effects (short-term unconsciousness, followed by cardiovascular signs and, later, signs of general malaise), which if not lethal, disappeared in a short time. It was found that the intravenous LD50 was greater than 43 mg active ingredient/kg body weight in the males and 76 mg active ingredient/kg body weight in the females. An intramuscular injection of Ukrain (1 g/30 ml) in the maximum technically feasible dose induced some transient signs of minor clinical importance which did not become life threatening. In both sexes the intramuscular LD50 was greater than 165 mg active ingredient/kg body weight.     

Pharmacokinetics of amikacin in children and neonates

To evaluate pharmacokinetics of amikacin (AMK), one of the aminoglycoside antibiotics, children with ages from 2 days to 11 years were treated with various doses by various administration routes, and both plasma and urinary levels of AMK were determined. The following is a summary of the results obtained: 1. Of 6 children, three were treated with 2.0 mg/kg of AMK by a 30-minute intravenous drip infusion, and the other 3 with 4.0 mg/kg by a 60-minute. Peaks of average plasma levels were observed at the ends of the infusions in both cases, and their levels were 9.23 and 13.67 micrograms/ml, respectively, showing a dose-dependency. Both half-lives and areas under plasma concentration-time curves (AUCs) were similar to those of adults. However, the volume of distribution (Vd) showed a lower value than that of adults. Peaks of average urine levels were 149.3 micrograms/ml with 2.0 mg/kg in 0-2 hours after the start of the infusion and 223.3 micrograms/ml with 4.0 mg/kg in 2-4 hours. Average urinary recovery rates within 6 hours after the start of the infusion were 95.4% with 2.0 mg/kg and 85.7% with 4.0 mg/kg. These recoveries were equal to or higher than that of adults. 2. When 3.0, 4.0 and 6.0 mg/kg of AMK were administered to 3 groups of mature or premature babies by intramuscular injection, average peak levels of AMK in plasma were 6.26, 8.61 and 12.60 micrograms/ml, respectively, at 30 minutes after the injection, showing dose-dependency. In these groups, the younger the day age after birth was, the longer the half-life became. The AUCs were larger as the half-life became longer. The Vd was larger than that in the intravenous drip infusion group, but, any particular was not observed. Average peak levels of AMK in urine were 78.83 micrograms/ml at 4-6 hours with a dose level of 3.0 mg/kg, 99.17 micrograms/ml at 2-4 hours with 4.0 mg/kg and 139.20 micrograms/ml at 0-2 hours with 6.0 mg/kg. Average urinary recovery rates within 6 hours were 36.57% with 3.0 mg/kg, 34.67% with 4.0 mg/kg and 43.77% with 6.0 mg/kg. These recovery rates were markedly lower than those observed in adults and children. One of the causes of this low recovery is that mature and premature babies have immature renal functions. 3. When 3.0 mg/kg of AMK was administered to three premature babies by a 30-minute intravenous drip infusion, the average peak plasma levels was 7.61 micrograms/ml at the end of the drip infusion.(ABSTRACT TRUNCATED AT 400 WORDS)     

DIESEL EXHAUST AFFECTS THE ABNORMAL DELIVERY IN PREGNANT MICE AND THE GROWTH OF THEIR YOUNG

To clarify the toxic effects of diesel exhaust (DE) on delivery in mice and on growth of young, C57Bl-strain females were exposed to 0.3, 1.0, or 3.0 mg diesel exhaust particles (DEP)/m 3 or filtered clean air (control) for 4 mo (12 h/day, 7 days/wk). After exposure, some females from each group were examined by necropsy, and the remainders were mated with unexposed males. Estrous females for necropsy who had been exposed to 1.0 mg DEP/m 3 had significantly lower uterine weights than the control estrous females. In the mated females, 9.1, 10.0, or 25.0% (0.3, 1.0, or 3.0 mg DEP/m 3) of the pregnancies resulted in abnormal deliveries (abortion and unable delivery), but this was not significant. The rate of good nest construction by delivered females exposed to 3.0 mg DEP/m 3 was significantly lower. Young were weighed at 11, 14, and 21 days, and weekly from wk 4 to 9 after birth. Body weights of male young of dams exposed to 1.0 or 3.0 mg DEP/m 3 were significantly lower at 6 and 8 wk of age. Body weights of female young of dams exposed to 1.0 or 3.0 mg DEP/m 3 were also significantly lower at 6, 8, and 9 wk. Vaginal orifices of young female mice whose dams were exposed to 0.3 and 1.0 mg DEP/m 3 opened significantly earlier. The young were killed at 30 or 70 days during deep anesthesia, and their body weights, organ weights, and body lengths were measured. Anogenital distance (AGD) of 30-day-old males whose dams were exposed to 0.3 mg DEP/m 3 was significantly shorter than that of the controls. Weights of thymus and ovary in 30-day-old females whose dams were exposed to 3.0 mg DEP/m 3 were significantly lower. In 70-day-old males of dams exposed to 3.0 mg DEP/m 3, body weights were significantly lower and AGD was significantly shorter. Weights of adrenals, testes, and seminal vesicles in 70-day-old males with dams exposed to 1.0 mg DEP/m 3 were significantly lower. In 70-day-old females with dams exposed to DE, body weights in the 3.0-mg DEP/m 3 group were significantly lower, and weights of adrenals, liver, and thymus in the 1.0-mg DEP/m 3 group were significantly lower. Thymus weights in 70-day-old females with dams exposed to 0.3 mg DEP/m 3 were significantly lower. Crown-rump length (CR) in 70-day-old females with dams exposed to 1.0 or 3.0 mg DEP/m 3 was significantly shorter. These results show that toxic substances in DE might cause abnormal delivery in mice, and that exposed females affected the growth and sexual maturation of their young.     

Beneficial effects of aluminum on the progression of lead-induced nephropathy in rats

We studied the effect of aluminum on lead-induced nephropathy in male albino rats. Five groups of male albino rats were given either water only or lead acetate (125 mg/kg body weight) and/or aluminum chloride (50 mg/kg body weight or 100 mg/kg body weight) for a period of 90 days. Aluminum was found to prevent the lead-induced increase in the relative organ (kidney) weight in a dose-dependent manner. Aluminum also prevented lead-induced increase in plasma creatinine levels of the treated animals. Estimation of lead concentration in kidneys of different treatment groups revealed that the net deposition of lead was lower in animals which were given both lead acetate and aluminum chloride simultaneously. The results showed that aluminum offers some protection against lead-induced nephrotoxicity in a time- and dose-dependent manner.     

Acute alcohol intoxication and body composition in women and men

The present study was a direct experimental comparison of administering equivalent alcohol doses based on body weight and estimated total body water to 12 women and 12 men. Each subject participated in two experimental sessions separated by at least three days. Two doses of 95% ethanol were administered in a randomized, counterbalanced order: 0.66 ml/kg of body weight, and 1.2 ml/l of total body water. Women were tested during the midfollicular phase of their menstrual cycle when plasma concentrations of estrogen and progesterone have been found to be lower than other phases of the cycle. When given doses equated for body weight, women reached significantly higher peak blood alcohol concentrations than men. No sex differences were found when equivalent doses based on total body water were administered. This differential effect of dose determination was not reflected in self-reported levels of alcohol intoxication. The anthropometric equations used to estimate total body water provided a practical, reliable method for equating alcohol doses.     

Beneficial Effects of Aluminum on the Progression of Lead‐Induced Nephropathy in Rats

We studied the effect of aluminum on lead‐induced nephropathy in male albino rats. Five groups of male albino rats were given either water only or lead acetate (125 mg/kg body weight) and/or aluminum chloride (50 mg/kg body weight or 100 mg/kg body weight) for a period of 90 days. Aluminum was found to prevent the lead‐induced increase in the relative organ (kidney) weight in a dose‐dependent manner. Aluminum also prevented lead‐induced increase in plasma creatinine levels of the treated animals. Estimation of lead concentration in kidneys of different treatment groups revealed that the net deposition of lead was lower in animals which were given both lead acetate and aluminum chloride simultaneously. The results showed that aluminum offers some protection against lead‐induced nephrotoxicity in a time‐ and dose‐dependent manner.