• Toxicological Research
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• v.23 no.2
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• pp.151-158
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• 2007

tert-Butyl acetate is an organic solvent used for coatings, industrial cleaning, and surface treatment applications. This study investigated the potential adverse effects of tert-butyl acetate on pregnant dams and embryo-fetal development after maternal exposure on gestational days 6 through 19 in rats. The test chemical was administered to pregnant rats by gavage at dose levels of 0, 500, 1,000, 1,500, and 2,000 mg/kg/day. All dams were subjected to a caesarean section on day 20 of gestation and their fetuses were examined for any external, visceral, and skeletal abnormalities. At 2,000 mg/kg, treatment-related clinical signs, including piloerection, abnormal gait, decreased locomotor activity, loss of fur, reddish tear, anorexia, nasal discharge, vocalization and coma, were observed in a dose-dependent manner. All dams died between the 2nd day and 5th day of treatment due to a severe systemic toxicity. At 1,500 mg/kg, minimal maternal toxicity including an increase in the incidence of decreased locomotor activity and loss of fur, and an increase in the weights of adrenal glands and liver was observed. On the contrary, no significant adverse effect on the embryo-fetal development was detected. There were no adverse effects on either pregnant dams or embryo-fetal development at <1,000 mg/kg. These results show that a 14-day repeated oral dose of tert-butyl acetate in rats caused a minimal maternal toxicity including increases in the incidence of clinical signs and the weights of adrenal glands and liver, but no embryotoxicity and teratogenicity at 1,500 mg/kg/day. Under these experimental conditions, the no-observed-adverse-effect level (NOAEL) of tert-butyl acetate is estimated to be 1,000 mg/kg per day for dams and 1,500 mg/kg per day for embryo-fetal development.

• Toxicological Research
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• v.24 no.4
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• pp.307-314
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• 2008

The present study was carried out to investigate the potential adverse effects of 1,3-dichloro-2-propanol on pregnant dams after maternal exposure during the gestational days (GD) 6 through 19 in Sprague-Dawley rats. The tested chemical was administered orally to pregnant rats at dose levels of 0, 10, 30, or 90 mg/kg/day. During the test period, clinical signs, mortality, body weights, food consumption, serum biochemistry, gross findings, organ weights, and Caesarean section findings were examined. In the 90 mg/kg group, decreases in the body weight gain and food consumption, and increases in the weights of liver and adrenal glands were observed. Serum biochemical investigations revealed increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholesterol (CHO), triglyceride (TG), alkaline phosphatase (ALP), and bilirubin (BIL) and decreases in glucose (GLU), albumin (ALB) and total protein (TP). In the 30 mg/kg group, a decrease in the food consumption and an increase in the liver weight were observed. Serum biochemical investigation also showed increases in CHO and TG and a decrease in glucose. Since there were no signs of maternal toxicity in the 10 mg/kg group, it is considered to be the no-observed-adverse-effect level (NOAEL) of 1,3-dichloro-2-propanol. It is concluded that successive oral administration of 1,3-dichloro- 2-propanol to pregnant rats for 14 days may cause significant toxicities in body weight and liver at a dose rate ${\geq}$ 30 mg/kg/day.

• Korean Journal of Veterinary Research
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• v.39 no.2
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• pp.276-286
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• 1999

In the present study, to understand how gonadotropin-releasing hormone (GnRH) affects ovarian functions in superovulated rats, we examined the effects of GnRH agonist on the ovulatory response, the morphological normality and nuclear maturation of ovulated oocytes, the ovarian weight, the ovarian histology, and the circulating steroid hormone ($17{\beta}$-estradiol, progesterone and testosterone) levels in immature rats pretreated with 30IU pregnant mare serum gonadotropin (PMSG) and supplemented with 10IU human chorionic gonadotropin(hCG). GnRH agonist was intravenously injected via jugular vein catheter every 20min for 4hrs in early follicular phase (from 6hr after PMSG) of superovulated rats. In addition, GnRH antagonist, Antide, was intravenously injected in combination with GnRH agonist to verify the effects of GnRH agonist on ovarian functions. All animals were sacrificed at 72hr after PMSG administration. The administration with GnRH agonist in early follicular phase of superovulated rats caused inhibition of ovulatory response, increased the proportion of abnormal appearing oocytes(especially, in the rats of the group treated with 500ng GnRH agonist), decreased ovarian weight and promote follicular atresia, compared to those from the rats of control regimen that were not treated with GnRH agonist. In addition, the treatment with GnRH agonist in the superovulated rat distinctly decreased serum steroid hormone ($17{\beta}$-estradiol, progesterone and testosterone) levels in preovulatory phase. On the other hand, the inhibitory effects of GnRH agonist treatment in superovulation-pretreated rats on ovarian functions were totally reversed by the combination with GnRH antagonist, Antide. The nuclear maturation of oocytes recovered from the oviducts in immature rats treated with GnRH agonist and/or GnRH antagonist was characterized by prematurity and asynchronization in early follicular phase, which was similar to control group. The overall results of this study indicate that GnRH agonist disturbs directly ovarian function in early follicular phase of superovulated immature rats in terms of ovulatory response and morphological normality of ovulated oocytes. This concept has been further evidenced by the findings of a great decrease in ovarian weight, a marked increase in follicular and a distinct decrease circulating steroid hormone ($17{\beta}$-estradiol, progesterone and testosterone) levels in GnRH agonist treatment regimen in early follicular phase.

• Environmental Mutagens and Carcinogens
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• v.21 no.2
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• pp.77-81
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• 2001

Kamijadowhan (KMD), an oriental herbal medicine used for anti-angiogenic effect, was extracted with 80% ethanol from mixture of source materials and lyophilized. KMD was orally administered to plugpositive pregnant rats from gestational days 12 to 20, dividing into three groups including vehicle-treated control, 0.5 g/kg or 3 g/kg KMD-treated groups. Dam weight during gestation and post-gestation, weight of pre- and post-weaning offsprings in male and female, and reproductive and developmental endpoints including incisor eruption, eye opening and testes descent were measured. No significant alterations in development of physical landmarks in offspring, maternal weight gain during gestation and post-gestation, and offspring weight were observed in KMD-treated group. The measurement of organ weight at post-gestational days 21 was not changed in dams. In 0.5 g/kg KMD-treated rats, kidney weights in male and female offsprings were significantly increased, and the body weight in male offspring was also increased. Liver and brain weights were not changed. Taken together, these data suggest that KMD may not significantly cross the placenta and produce no reproductive and developmental toxicity at maternally non-toxic dosages.

• Environmental Analysis Health and Toxicology
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• v.26
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• pp.6.1-6.8
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• 2011

Objectives: The present study investigated the potential adverse effects of multi-wall carbon nanotubes (MWCNTs) on pregnant dams and embryonic development following maternal exposure in rats. Methods: MWCNTs were orally administered to pregnant rats from gestational day (GD) 6 through 19 at dose levels of 0, 8, 40, 200, and 1000 mg/kg/day. During the test period, clinical signs, mortality, body weights, food consumption, serum biochemistry, oxidant-antioxidant status, gross findings, organ weights, and Caesarean section findings were examined. Results: All animals survived to the end of the study. A decrease in thymus weight was observed in the highest dose group. However, maternal body weight, food consumption, serum biochemical parameters, and oxidant-antioxidant balance in the kidneys were not affected by treatment with MWCNTs. No treatment-related differences in gestational index, embryo-fetal mortality, or fetal and placental weights were observed between treated and control groups. Conclusions: The results show that 14-day repeated oral dosing of MWCNTs during pregnancy induces minimal maternal toxicity at 1000 mg/kg/day in rats. Under these experimental conditions, the no-observed-adverse-effect level of MWCNTs is considered to be 200 mg/kg/day for dams and 1000 mg/kg/day for embryonic development.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.601-607
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• 1994

This study was carried out to investigate the potential of phenol to induce embryotoxicity in the Sprague-Dawley rat. Seventy mated rats were distributed among three treated troups, a vehicle control group and a negative control group. Phenol was at dose levels of 20, 60 and 180mg/kg/day adminsistered by gavage to pregnant rats three times per day from days 7 to 12 of gestation. All dams were subjected to the caesarean section on day 20 of gestation. At 120mg/kg, dams exhibited decreased locomotivity. In addition, both weight reduction and retarded ossification of fetuses were observed. There were no signs of maternal toxicity or embryotoxicity at 20 and 60mg/kg. The results show that phenol induces fetal growth retardation at maternally subtoxic dose in rats.

• Journal of the Korean Home Economics Association
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• v.20 no.1
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• pp.57-64
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• 1982

This study was designed to observe the effect of two levels of dietary protein intake on the development and growth of rats from fetus to adult. The pregnant rats were fed either 20% casein diet or 7% casein diet. After weaning or two weeks postweaning, some of the pups from malnourished mothers were rehabilitated by feeding 20% casein diet. The results were. 1. On the 14th day of gestation, no differences were found in weight and total body fat or protein between fetuses from dams fed 7% casein diet and those from those from 20% casein diet. 2. The birth weight of the pups from 7% casein diet group were significantly lower than those from 20% casein diet group. 3. After rehabilitation, the total body fat and protein of low protein group were not different from those of control group when they were compared at the same body weights regardless the age of rats or the duration on the low protein diet. 4. The nitrogen retention of low protein group, after rehabilitation, was higher than that of control group when they were compared at the same body weight.

• The Journal of the Korean dental association
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• v.15 no.9
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• pp.749-753
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• 1977

The author studied the effects of anticancer Endoxan to the rat's teeth. Two hundred pregnant rats were used. The experimental rats were given an intramuscular injection of Endoxan as nitrogen mustard derivatives 10mg. per 40gm of body weight. In order to investigate effects of Endoxan to the teeth of rats the control and experimental rats group wee sacrificed on 1,3,5,7 and 14days, and made preparation for histopathologic findings. The rusults were as follows: 1. In several days (about 5days) after injection of Endoxan, tooth germs of cap stage, bell stage, and dental lamina were irregular arranged form as compared with in the control group teeth. 2. Irregular arranged cell were recovered from 14days after injection of Endoxan.

• Journal of Veterinary Clinics
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• v.18 no.1
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• pp.48-54
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• 2001

The effects of PMSG and/or prostaglandin analogue, cloprostenol, on the prevention of implantation, termination of pregnancy, concentration of plasma progesterone, and Na and K contents of the plasma and uterine fluid were studied in pregnant rats. PMSG 50 or 100 IU concomitant with cloprostenol 90 or 180 mg were administered once on day 3 or 9 of gestation. Rats were autopsied on days 8, 10 or 21 gestation. A single administration of PMSG resulted in increasing the number of corpora lutea, preventing implantation and terminating pregnancy. A single administration of cloprostenol had no effect on the prevention of implantation and termination of pregnancy but was able to induce the termination of pregnancy administering at large doses on day 9. A single administration of PMSG concomitant with cloprostenol ws found to be very increased the number of corpora lutea and to be 100% effective in preventing implantation and to be nearly 100% effective in terminating pregnancy. It is uncommon that a single dose of PMSG 50 IU concomitant with cloprostenol 90 or 180 mg on day 9 was able to maintain the pregnancy at very low rates of 0.3∼5.3%. Concentration of plasma progesterone and Na and K contents of the plasma and uterine fluid were increased or decreased administering PMSG and/or cloprostenol, but had no effect on preventing implantation and terminating pregnancy.

• Journal of Life Science
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• v.11 no.5
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• pp.447-456
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• 2001

We have recently demonstrated that the fluoroquinolone antibacterial DW-116 caused a significant developmental toxicity in rats. The present study was conducted to determine whether the development toxicity induced by DW-116 treatment was the result of malnutrition fro reduced food intake or the direct effects of test chemical on conceptuses. The test chemical was administered by gavage to pregnant rats from gestational days 6 through 16 at dose levels of 0 and 500 mg/kg/day. A pair-feeding study was also performed in which the pregnant rats received the same amount of diet consumed by the DW-116-treated pregnant rats. All dams were subjected to caesarean section on day 20 of gestation and their fetuses were examined for examined for external, visceral, and skeletal abnormalities. In this treatment group, the maternal toxicities included increased abnormal clinical signs, decreased maternal body weight, suppressed body weight gain during treatment and posttreatment periods, and reduced food intake. The significant developmental toxicities included increased fetal deaths, decreased live fetuses, reduced fetal body weight and placental weight, increased incidence of fetal abnormalities, and increased fetal ossification delay. In this pair-fed group, however, slight maternal toxicities including decreased body weight and suppressed body weight gain during treatment period were observed in comparison with the control group, and minimal development toxicities including reduced fetal and placental weights and increased fetal ossification delay were found. The number of fetal deaths and live fetuses, and the incidences of malformed fetuses and litters with affected fetuses were comparable to the control values. Based on the results, it could be concluded that the development toxicity observed in the treatment group is attributable to the direct effects of Dw-116 treatment, but not to the maternal malnutrition from reduced food consumption during pregnancy.