Pre- and postnatal development studies of lasofoxifene, a selective estrogen receptor modulator (SERM), in Sprague-Dawley rats

BACKGROUND: Lasofoxifene is a nonsteroidal selective estrogen receptor modulator (SERM) developed for the treatment of postmenopausal osteoporosis. The purpose of these studies was to evaluate the effects of lasofoxifene on the postnatal development, behavior, and reproductive performance of offspring of female rats given lasofoxifene during organogenesis and lactation. METHODS: Two range-finding studies were conducted to determine the effects of lasofoxifene at doses from 0.01-10 mg/kg on parturition and lactation in pregnant rats and on the early postnatal development of the offspring, and to optimize the dosing regimen. Maternal milk and plasma were sampled for concentrations of lasofoxifene on Lactation Days 4, 7, and 14. In the pre- and postnatal development study, lasofoxifene was administered to pregnant and lactating rats by oral gavage at dose levels of 0.01, 0.03, and 0.1 mg/kg on Gestation Days 6-17 and Lactation Days 1-20. Maternal body weight and food consumption were measured throughout pregnancy, and body weight was measured throughout lactation. Parturition was monitored closely. The F1 offspring were measured for viability, body weight, anogenital distance, the appearance of postnatal developmental indices and reflex behaviors, sensory function, in an age-appropriate functional observational battery, motor activity, auditory startle, passive avoidance, and the Cincinnati Water Maze. The F1 generation was assessed for reproductive function, and the F2 offspring were measured for body weight and viability throughout the lactation period. RESULTS: In the range-finding studies, indications of maternal toxicity included decreased body weight and food consumption, increased length of gestation, prolonged parturition, dystocia, and increased offspring mortality at birth. Concentrations of lasofoxifene in maternal plasma were similar to those in milk, increased with increasing dose, and remained consistent over a 10-day period. In the pre- and postnatal development study, maternal body weights and food consumption were decreased in all treated groups during gestation. Length of gestation was increased, parturition was prolonged, and dystocia was noted in the dams in the 0.1 mg/kg group. There was increased pup mortality in the F1 litters in the 0.1 mg/kg group and all treated groups had decreased offspring body weights beginning at 1 week of age, continuing into the postweaning period and, for the F1 males, into adulthood. Female F1 offspring in the 0.03 and 0.1 mg/kg groups had increased body weights as adults. There were delays in the age of appearance of preputial separation in the males in the 0.1 mg/kg group and vaginal opening in the females in all treated groups. Body temperature was decreased by <0.5 degrees C after weaning for male and female offspring in the 0.1 mg/kg group. The sensory, behavioral, and functional measures, including the tests of learning and memory, were unaffected by treatment. Mating success was lower for the F1 animals in the 0.1 mg/kg group, but there were no effects on the reproductive parameters. Mating, reproduction, and maternal behavior of the F1 animals in the 0.01 and 0.03 mg/kg groups and the survival and body weights of the F2 offspring in all treated groups through Postnatal Day 21 were unaffected by treatment. CONCLUSION: The maternal findings in this study were related to the pharmacologic activity of lasofoxifene. Inhibition of growth of the F1 offspring after perinatal exposure to lasofoxifene was observed, but there were no significant effects on the sensory, behavioral, or functional measures, including learning and memory. There were no effects on the F2 generation. The findings are consistent with those reported for at least one other SERM. The findings of this study do not suggest increased risk for the primary indication of use in postmenopausal women.     

Two generation reproduction study of ethylbenzene by inhalation in Crl-CD rats

BACKGROUND: This study was conducted to evaluate the potential adverse effects of ethylbenzene (EB) on reproductive capability from whole-body inhalation exposure of F0 and F1 parental animals. METHODS: Four groups of Crl:CD(SD)IGS BR rats (30/sex/group for F0 and 25/sex/group for F1) were exposed to 0, 25, 100, and 500 ppm EB for 6 hr/day for at least 70 consecutive days before mating. Inhalation exposure for the F0 and F1 females continued throughout mating, gestation through gestation day (GD) 20, and lactation days (LD) 5-21. On LD 1-4, females received EB in corn oil via oral gavage at dose levels of 26, 90, and 342 mg/kg/day (divided into three equal doses, approximately 2 hr apart), as calculated from a physiologically-based pharmacokinetic (PBPK) model to provide similar maternal blood area-under-concentration (AUC) as provided by inhalation. Pups were weaned on postnatal day (PND) 21 and exposure of the F1 generation started on PND 22. Estimates of internal exposure were determined by measuring EB concentrations in blood collected from F1 dams (4/group) and their culled pups 1 hr after the last gavage dose on PND 4. On PND 22, blood was collected from these same F1 dams and their weanlings for EB analysis 1 hr after a 6-hr inhalation exposure. The remainder of the F2 generation was not directly exposed. RESULTS: EB exposure did not affect survival or clinical observations. Male rats in the 500 ppm group in both generations gained weight more slowly than the controls. There were no indications of adverse effects on reproductive performance in either generation. Male and female mating and fertility indices, pre-coital intervals, spermatogenic endpoints, ovarian follicle counts, reproductive organ weights, lengths of estrous cycle and gestation, live litter size, pup weights, developmental landmarks, and postnatal survival were unaffected. No adverse exposure-related macroscopic pathology was noted at any level. CONCLUSIONS: Increased liver weights were found in the animals exposed to 500 ppm. F1 maternal whole blood EB concentrations of 0.49, 3.51, or 18.28 mg/L were found 1 hr after administration of a composite oral dose of 26, 90, or 342 mg/kg/day, respectively, but no detectable EB was found in blood samples of their F2 PND 4 culled pups. F1 maternal mean whole blood EB levels 1 hr after a 6-hr inhalation exposure on postpartum day (PPD) 22 was 0.11 mg/L (25 ppm), 0.56 mg/L (100 ppm), and 11 mg/L (500 ppm). For the offspring exposed with their dams on PND 22, F2 pup blood EB concentrations ranged from 0.017-0.039 mg/L (25 ppm), 0.165-0.465 mg/L (100 ppm), and 8.82-15.74 mg/L (500 ppm). Because decreased weight gain in the 500 ppm males was transient and no histopathological changes were associated with the increased liver weights in the 500 ppm male and female groups, these changes were not considered adverse. Therefore, for parental systemic toxicity, 100 ppm was considered a NOEL and 500 ppm a NOAEL in this study. The 500 ppm exposure concentration was considered a NOAEL for F0 and F1 reproductive toxicity and offspring developmental endpoints.     

An Enhanced Pre‐ and Postnatal Development Study in Cynomolgus Monkeys with Tabalumab: A Human IgG4 Monoclonal Antibody

Tabalumab, a human IgG4 monoclonal antibody (mAb) with neutralizing activity against both soluble and membrane B‐cell activating factor (BAFF), has been under development for the treatment of autoimmune diseases. The purpose of this study was to determine the potential adverse effects of maternal tabalumab exposure on pregnancy, parturition, and lactation of the mothers and on the growth, viability, and development of the offspring through postnatal day (PND) 204. Tabalumab was administered by subcutaneous injection to presumed pregnant cynomolgus monkeys (16–19 per group) every 2 weeks from gestation day (GD) 20 to 22 until parturition at doses of 0, 0.3, or 30 mg/kg. Evaluations in mothers and infants included clinical signs, body weight, toxicokinetics, blood lymphocyte phenotyping, T‐cell‐dependent antibody response (infants only), antitherapeutic antibody (ATA), organ weights (infants only), and gross and microscopic histopathology. Infants were also examined for external and visceral morphologic and neurobehavioral development. There were no adverse tabalumab‐related effects on maternal or infant endpoints. An expected pharmacological decrease in peripheral blood B‐lymphocytes occurred in adults and infants; however, B‐cell recovery was evident by PND154 in adults and infants at 0.3 mg/kg and by PND204 in infants at 30 mg/kg. At 30 mg/kg, a reduced IgM antibody response to T‐cell‐dependent antigen keyhole limpet hemocyanin (KLH) was observed following primary immunization. Following secondary KLH immunization, all infants in both dose groups mounted anti‐KLH IgM and IgG antibody responses similar to control. Placental and mammary transfer of tabalumab was demonstrated. In conclusion, the no‐observed‐adverse‐effect level for maternal and developmental toxicity was 30 mg/kg, the highest dose tested. Exposures at 30 mg/kg provide a margin of safety of 16× the anticipated clinical exposure.     

Developmental Toxicity of the HMG‐CoA Reductase Inhibitor (PPD10558) in Rats and Rabbits

PPD10558 is an orally active, lipid‐lowering 3–hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase inhibitor (statin) being developed as a treatment for hypercholesterolemia in patients who have not been able to tolerate statins because of statin‐associated myalgia. We have studied the potential developmental toxicity effects of PPD10558 in pregnant rats and rabbits given daily oral doses during the period of organogenesis. Rats were dosed with 0, 20, 80, or 320 mg/kg/day from Gestation Day (GD) 6 to 17 and rabbits received dose levels of 0, 12.5, 25, or 50 mg/kg/day from GD 6 to 18. Additional groups in both studies served as toxicokinetic animals and received the PPD10558 in the same manner as the main study groups at the same dose levels. Blood samples were collected from toxicokinetic animals at designated time points on GD 6 and 17 in rats and GD 6 and 18 in rabbits. Fetal exposure in rats was assessed on GD 20. Maternal and developmental parameters were evaluated in rats and rabbits on GD 20 and GD 29, respectively. No maternal and developmental toxicity was observed at any of the dose levels used in the rat study. Evidence of fetal exposure was determined in fetal plasma with mean fetal concentrations of PPD10558 and the metabolite (PPD11901) found to be between 1 and 6% of the mean maternal concentrations. In rabbits, marked maternal toxicity including mortality (eight deaths; 1 dose at 25 and 7 at 50 mg/kg/day), abortions (2 at 25 mg/kg/day and 6 at 50 mg/kg/day) and reduction in gestation body weight, gestation body weight changes and decreased food consumption were observed. In addition, fetal body weights of the combined sexes were significantly reduced at 50 mg/kg/day in comparison with the controls. Mean peak exposure (Cmax) and total exposure (AUC(0–24)) of PPD11901 in both rats and rabbits were higher than that of PPD10558 on GD 6 and GD 17 at each of the three dose levels.. Based on the results of these studies, the no observed adverse effect level (NOAEL) for maternal and developmental toxicity in rats was considered to be ≥320 mg/kg/day, the highest dose level used in the study. The NOAEL for maternal and developmental toxicity in rabbits was 12.5 mg/kg/day and 25 mg/kg/day, respectively.     

Two generation reproduction study of styrene by inhalation in Crl-CD rats

This study was conducted to evaluate the potential adverse effects of styrene on reproductive capability from whole-body inhalation exposure of F0 and F1 parental animals. Assessments included gonadal function, estrous cyclicity, mating behavior, conception rate, gestation, parturition, lactation, and weaning in the F0 and F1 generations, and F1 generation offspring growth and development. Four groups of male and female Crl:CD(SD)IGS BR rats (25/sex/group) were exposed to 0, 50, 150, and 500 ppm styrene for 6 hr daily for at least 70 consecutive days prior to mating for the F0 and F1 generations. Inhalation exposure for the F0 and F1 females continued throughout mating and gestation through gestation day 20. Inhalation exposure of the F0 and F1 females was suspended from gestation day 21 through lactation day 4. On lactation days 1 through 4, the F0 and F1 females received styrene in virgin olive oil via oral gavage at dose levels of 66, 117, and 300 mg/kg/day (divided into three equal doses, approximately 2 hr apart). These oral dosages were calculated to provide similar maternal blood peak concentrations as provided by the inhalation exposures. Inhalation exposure of the F0 and F1 females was re-initiated on lactation day 5. Styrene exposure did not affect survival or clinical observations. Rats in the 150- and 500-ppm groups in both parental generations gained weight more slowly than the controls. There were no indications of adverse effects on reproductive performance in either the F0 or F1 generation. Male and female mating and fertility indices, pre-coital intervals, spermatogenic endpoints, reproductive organ weights, lengths of estrous cycle and gestation, live litter size and postnatal survival were similar in all exposure groups. Additionally, ovarian follicle counts and corpora lutea counts for the F1 females in the high-exposure group were similar to the control values. No adverse exposure-related macroscopic pathology was noted at any exposure level in the F0 and F1 generations. A previously characterized pattern of degeneration of the olfactory epithelium that lines the dorsal septum and dorsal and medial aspects of the nasal turbinates occurred in the F0 and F1 generation animals from the 500-ppm group. In the 500-ppm group, F2 birthweights were reduced compared to the control and F2 offspring from both the 150- and 500-ppm exposure groups gained weight more slowly than the controls. Based on the results of this study, an exposure level of 50 ppm was considered to be the NOAEL for F0 and F1 parental systemic toxicity; the NOAEL for F0 and F1 reproductive toxicity was 500 ppm or greater.     

Reproductive and Developmental Toxicity of Orally Administered Botanical Composition,UP446‐Part II: Effects on Prenatal and Postnatal Development,Including Maternal Function in Sprague–Dawley Rats

Almost all herbal remedies could be therapeutic at one dose and toxic at another. These facts become more troubling and a double threat when uncharacterized medicinal herbs are blended together and used by expectant mothers as a supplement to conventional pregnancy management with an inherent belief of considering herbal remedies as harmless. Here we describe the potential adverse effects of UP446, a standardized bioflavonoid composition from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu, on the maternal and their first filial generation (F1) developmental and functional toxicity following exposure at doses of 250, 500, and 1000 mg/kg/day. Maternal gestation, viability index, sex ratio, body weight, and food consumption were evaluated. F1 growth and development, sexual function including mating index, fertility, implantation, and embryo mortality were also assessed. Test substance impacts on the maternal (F0) or F1 reproductive parameters were very minimal. There were no statistically significant differences in implantation, parturition, viability, and neonates’ sex ratios. There were no significant changes in maturation, behavioral, or functional developments between groups. No treatment‐related prenatal or postnatal in‐life or necropsy abnormalities were observed. Therefore, the no observed adverse effect level in the prenatal and postnatal developments, including maternal function study was considered to be greater than 1000 mg/kg     

Review of reproductive and developmental toxicity studies with isopropanol

Published studies for reproductive and developmental toxicity conducted with isopropanol have been conducted by the inhalation and oral gavage routes of administration. Interpretation of the data from these studies has resulted in discussions regarding NOAELs and additional benchmark dose modeling publications. Unpublished reproductive and developmental toxicity studies administered in the drinking water were also conducted by BIBRA, and the results of those studies are presented here. In addition, all of the reproductive and developmental toxicity studies conducted with isopropanol are summarized and evaluated for concordance of effects and NOAELs. Endpoints of concern for regulatory agencies were decreases in male mating index and reductions in postnatal pup survival. Original study reports were evaluated and data collated to address these two endpoints, and the data summarized. Data are presented suggesting that there were technical problems in the study that implied a decrease in male mating index, and based on the results from the drinking water studies, the weight of evidence suggests that isopropanol does not affect male mating or fertility at dose levels of up to 1000 mg/kg/day. The weight of evidence suggests that isopropanol can cause decreases in postnatal pup survival following oral gavage administration of 1000-1200 mg/kg/day to the dams. The NOAEL for this endpoint with oral gavage administration was 700 mg/kg/day. Indications of maternal toxicity were also an important predictor for decreased postnatal survival. Decreased postnatal pup survival was also noted in the drinking water studies with isopropanol with a LOAEL of 2278 mg/kg/day and a NOAEL of 1947 mg/kg/day.     

Two-generation reproduction study of di-2-ethylhexyl terephthalate in Crl:CD rats

BACKGROUND: This study was conducted to evaluate the potential adverse effects of di-2-ethylhexyl terephthalate (DEHT) on reproductive capability from exposure of F(0) and F(1) parental animals. METHODS: Four groups of male and female Crl:CD (SD)IGS BR rats (30/gender/group) were exposed to 0, 0.3%, 0.6%, and 1.0% DEHT in the feed for at least 70 consecutive days before mating for the F(0) and F(1) generations. Exposure for the F(0) and F(1) males continued throughout the mating period until euthanasia. Exposure for the F(0) and F(1) females continued throughout mating, gestation, and lactation. The F(1) and F(2) pups were weaned on postnatal day (PND) 21. Assessments included gonadal function, estrous cyclicity, mating behavior, conception rate, gestation, parturition, lactation, and weaning in the F(0) and F(1) generations, and F(1) generation offspring growth and development. RESULTS: DEHT exposure did not affect clinical observations. However, lethality was observed in F(0) and F(1) dams consuming the 1.0% diet during the post-weaning period. No treatment-related mortality occurred in any of the male groups exposed to DEHT or in the female groups exposed to 0.3% or 0.6% DEHT. Male rats consuming the 1.0% diet in both parental generations gained weight more slowly than the controls. There were no indications of adverse effects on reproductive performance in either the F(0) or F(1) generation. Male and female mating and fertility indices, pre-coital intervals, spermatogenic endpoints, reproductive organ weights, lengths of estrous cycle and gestation, live litter size, developmental landmarks, and postnatal survival were similar in all exposure groups. Additionally, ovarian follicle counts for the F(1) females in the high-exposure group were similar to the control values. No adverse exposure-related macroscopic pathology was noted at any exposure level in the F(0) and F(1) generations. CONCLUSIONS: Increases in liver weights were found in the male and female animals exposed to 0.6% or 1.0% DEHT in the diet. Because there were no accompanying histopathologic changes, this effect was not considered adverse. Significant decreases in feed consumption in the female animals from the groups consuming 1.0% DEHT in the diet during lactation accompanied reduced postnatal pup body weights and rate of weight gain. Reductions in pup body weights later in lactation may also have been due to direct consumption of the treated feed by the pups or taste aversion to the same. Reduced relative spleen weight was found in male weanling pups from the 1.0% group in both generations and reduced relative spleen and thymus weights were found in female pups from the 1.0% group in the F(2) generation at necropsy on PND 21. Therefore, for parental and pup systemic toxicity, 0.3% DEHT in the diet (182 mg/kg/day) was considered no-observed-effect level (NOEL). The 1.0% DEHT (614 mg/kg/day) in the diet exposure concentration was considered a NOEL for F(0) and F(1) reproductive toxicity endpoints.     

Developmental toxicity evaluation of sodium thioglycolate administered topically to Sprague-Dawley (CD) rats and New Zealand White rabbits

BACKGROUND: Sodium thioglycolate, which has widespread occupational and consumer exposure to women from cosmetics and hair‐care products, was evaluated for developmental toxicity by topical exposure during the embryonic and fetal periods of pregnancy METHODS: Timed‐mated Sprague–Dawley rats (25/group) and New Zealand White (NZW) rabbits (24/group) were exposed to sodium thioglycolate in vehicle (95% ethanol:distilled water, 1:1) by unoccluded topical application on gestational days (GD) 6–19 (rats) or 6–29 (rabbits) for 6 hr/day, at 0, 50, 100, or 200 mg/kg body weight/day (rats) and 0, 10, 15, 25, or 65 mg/kg/day (rabbits). At termination (GD 20 rats; GD 30 rabbits), fetuses were examined for external, visceral, and skeletal malformations and variations. RESULTS: In rats, maternal topical exposure to sodium thioglycolate, at 200 mg/kg/day (the highest dose tested) on GD 6–19, resulted in maternal toxicity, including reduced body weights and weight gain, increased relative water consumption and one death. Treatment‐related increases in feed consumption and changes at the application site occurred at all doses, in the absence of increased body weights or body weight change. Fetal body weights/litter were decreased at 200 mg/kg/day, with no other embryo/fetal toxicity and no treatment‐related teratogenicity in any group. In rabbits, maternal topical exposure to sodium thioglycolate on GD 6–29 resulted in maternal dose‐related toxicity at the dosing site in all groups; no maternal systemic toxicity, embryo/fetal toxicity, or treatment‐related teratogenicity were observed in any group. CONCLUSIONS: A no observed adverse effect level (NOAEL) was not identified for maternal toxicity in either species with the dosages tested. The developmental toxicity NOAEL was 100 mg/kg/day (rats) and ≥65 mg/kg/day (rabbits; the highest dose tested). The clinical relevance of theses study results is uncertain because no data were available for levels, frequency, or duration of exposures in female workers or end users. Birth Defects Research Part B 68:144–161, 2003. © 2003 Wiley‐Liss, Inc.     

Embryotoxicity and teratogenicity of uranium in mice following subcutaneous administration of uranyl acetate

The effects of multiple maternal subcutaneous injections of uranyl acetate dihydrate (0.5, 1, and 2 mg/kg/d) from d 6 to d 15 of gestation were evaluated in Swiss mice. External, internal soft-tissue and skeletal examinations of fetuses were performed on gestation d 18. Maternal toxicity occurred in all uranium-treated groups as evidenced primarily by deaths as well as significant decreases in weight gain and in body weight at termination. Although it was not dose-related, embryotoxicity also occurred in all uranium-treated groups (significant increases in the number of nonviable implantations and in the percentage of postimplantation loss). Fetal body weight was significantly decreased at 1 and 2 mg/kg/d, whereas the number of total internal and total skeletal defects showed dose-dependent increases at 0.5, 1, and 2 mg/kg/d. Most morphological defects were developmental variations, whereas malformations were only detected at 1 and 2 mg/kg/d. On the basis of these data, both the maternal no-observable-adverse-effect level (NOAEL) and the NOAEL for embryotoxicity of uranyl acetate dihydrate were below 0.5 mg/kg/d, whereas the NOAEL for teratogenicity was 0.5 mg/kg/d.     

Separation of hepatic n-demethylase-inducing and opioid dependence-producing doses of levo-alpha-acetylmethadol in the pregnant rat

A 2.0 mg per kg oral dose of l-alpha-acetylmethadol (LAAM) administered daily to female rats prior to mating and throughout pregnancy increased ethylmorphine N-demethylase activity in liver microsomes of the dams measured 24 h after parturition. This dose of LAAM decreased maternal weight gain during gestation and increased postnatal mortality. However, 0.05 mg LAAM per kg was sufficient to produce dependence in the dams without affecting hepatic drug metabolism, gestational weight gain or neonatal mortality. The data indicate that it is not necessary to use doses of LAAM which can affect drug metabolizing enzymes in dams and increase pup mortality to maintain opioid-type physical dependence.     

TGF‐β1 monoclonal antibody: Assessment of embryo‐fetal toxicity in rats and rabbits

A humanized monoclonal antibody targeting transforming growth factor β1 (TGF‐β1 mab) has been used in development for the treatment of chronic kidney disease. Embryo‐fetal development studies were conducted in rats and rabbits using 30 and 25 animals per group, respectively. The TGF‐β1 mab was administered subcutaneously to rats at 0, 2, or 50 mg/kg/dose on gestation days (GDs) 6, 10, and 14 and intravenously to rabbits at 0 or 3 mg/kg/dose on GDs 7, 12 to 19, and at 30 mg/kg/dose on GDs 7, 12, 14, 16, and 18. Maternal reproductive endpoints and fetal viability, weight, and morphology were evaluated. There was no indication of maternal or embryo‐fetal toxicity in the rat. Effects in the rabbit were limited to the fetus where the 30 mg/kg TGF‐β1 mab dose produced a slight decrease in fetal weight and an increase in the incidence of retrocaval ureter and an absent and/or malpositioned kidney/ureter in two fetuses. In conclusion, TGF‐β1 mab produced no adverse maternal or embryo‐fetal findings in rats when administered ≤50 mg/kg on GDs 6, 10, and 14. TGF‐β1 mab did not demonstrate maternal toxicity or embryo‐fetal lethality at doses as high as 30 mg/kg when administered on GDs 7, 12, 14, 16, and 18 in rabbits. Fetal growth and morphology were affected only at 30 mg/kg; thus, the no observed adverse effect level was 3 mg/kg in rabbits. The margin of safety for both rats and rabbits was ≥37‐fold the clinical exposure level.     

Effects of oral meso-2,3-dimercaptosuccinic acid (DMSA) administration on late gestation and postnatal development in the mouse

The present study was conducted to evaluate the effects of meso-2,3-dimercaptosuccinic acid (DMSA) on late gestation and postnatal viability and growth in the mouse. DMSA was given po to four groups of pregnant Swiss mice at 0, 200, 400, and 800 mg/kg/day from day 14 of pregnancy until postnatal day 21. At birth, the following data were recorded: length of gestation, number of live, dead, and abnormal pups, sex, and individual pup weights. Each pup was weighed again on day 4, 14, and 21 of lactation. Pinna detachment, incisor eruption and eye opening were also monitored. No treatment-related signs of toxicity were noted in any of the dams during the study. No adverse effects on offspring survival or development were evident in the 200 or 400 mg DMSA/kg/day groups. However, on days 14 and 21 of lactation a significant decrease in pup body weight was observed in the 800 mg/kg/day group. Also, a significant increase in the relative weight of the brain was seen in this group. The "no observable effect level" (NOEL) for health hazards to the developing pup was greater than 400 mg/kg/day. This dose is higher than the amounts of DMSA usually given in the treatment of human heavy metal intoxications.     

Dose–Response Effects of Diphenylhydantoin on Pregnant Dams and Embryo‐Fetal Development in Rats

Despite the widespread use of diphenylhydantoin (DPH), there is a lack of reliable information on the teratogenic effects, correlation with maternal and developmental toxicity, and dose–response relationship of DPH. This study investigated the dose–response effects of DPH on pregnant dams and embryo‐fetal development as well as the relationship between maternal and developmental toxicity. DPHwas orally administered to pregnant rats from gestational days 6 through 15 at 0, 50, 150, and 300 mg/kg/day. At 300 mg/kg, maternal toxicity including increased clinical signs, suppressed body weight, decreased food intake, and increased weights of adrenal glands, liver, kidneys, and brain were observed in dams. Developmental toxicity, including a decrease in fetal and placental weights, increased incidence of morphological alterations, and a delay in fetal ossification delay also occurred. At 150 mg/kg, maternal toxicity manifested as an increased incidence of clinical signs, reduced body weight gain and food intake, and increased weights of adrenal glands and brain. Only minimal developmental toxicity, including decreased placental weight and an increased incidence of visceral and skeletal variations, was observed. No treatment‐related maternal or developmental effects were observed at 50 mg/kg. These results show that DPH is minimally embryotoxic at a minimal maternotoxic dose (150 mg/kg/day) but is embryotoxic and teratogenic at an overt maternotoxic dose (300 mg/kg/day). Under these experimental conditions, the no‐observed‐adverse‐effect level of DPH for pregnant dams and embryo‐fetal development is considered to be 50 mg/kg/day. These data indicate that DPH is not a selective developmental toxicant in the rat.     

Toxicokinetic Profile of N‐(2‐Aminoethyl)ethanolamine in the Female Wistar Rat and Distribution into the Late Gestation Fetus and Milk

N‐(2‐aminoethyl)ethanolamine (AEEA) caused aneurysms of the great vessels in rats exposed in utero and during the first days post partum, exacerbated by postnatal treatment of the lactating dams (Moore et al., 2012. Birth Defects Res B Dev Reprod Toxicol [95:116‐122]). The purpose of this work was to examine the systemic availability of AEEA during gestation and early lactation. The absorption of AEEA was determined following oral administration to nonpregnant and pregnant female Wistar rats. A single dose administered by gavage (0.5 or 50 mg/kg) on gestation day 18 was rapidly and extensively (>90%) absorbed from the gastrointestinal tract (absorption t_1/2 = 0.1–0.2 hr). Elimination from the plasma followed a biphasic pattern, with a rapid elimination phase (t_1/2 α = 1.6–1.8 hr) followed by a slower phase (t_1/2 β = 16.7–17.3 hr). Following repeated gavage administration during gestation day 17 to 19, ¹⁴C‐AEEA–derived radioactivity readily partitioned into the fetus and was evenly distributed therein, but cleared approximately twofold slower from the fetal blood and tissues than the maternal blood and chorioallantoic placenta. When administered to lactating dams during lactation days 1 to 12, ¹⁴C‐AEEA–derived radioactivity preferentially partitioned into the milk reaching levels that were between 1.6‐ and 2.5‐fold higher than the maternal blood. Although the concentration of AEEA equivalents in the maternal blood remained quite consistent, the concentration in the milk fell by almost 40% between lactation days 4 and 12, probably reflecting an increase in milk production over this same period. We confirm exposure of the offspring to AEEA both in utero and during lactation, but that AEEA does not appear to specifically concentrate in the great vessels.     

Developmental effects of boric acid in rats related to maternal blood boron concentrations

Timed-mated Sprague-Dawley rats (60/group) were exposed to boric acid (BA) from gestational days (gd) 0 to 20. BA added to the diet (0, 0.025, 0.050, 0.075, 0.1, or 0.2%) yielded boron (B) intakes of <0.35 (control), 3, 6, 10, 13, or 25 mg B/kg body wt/d. Approximately one-half of the dams/group were terminated on gd 20, maternal whole blood collected and frozen, and prenatal outcome (fetal growth, viability, and morphology) evaluated. Remaining dams received control diet beginning on gd 20, and litters were monitored throughout lactation. Blood samples were prepared by a high-temperature alkaline ashing method and analyzed for B by inductively coupled plasma (ICP) optical emission spectrometry. On gd 20, blood B concentrations of 1.27 +/- 0.298 and 1.53 +/- 0.546 microg B/g were associated with the no-observed-adverse-effect level (NOAEL) and lowest-observed-adverse-effect level (LOAEL) (10 and 13 mg B/kg/d, respectively) for developmental toxicity. Developmental toxicity persisted postnatally only at 25 mg B/kg/d, a dose associated with >10-fold increase in maternal blood B (2.82 +/- 0.987 vs. 0.229 +/- 0.143 microg B/g for controls). Maternal blood B concentrations were: 1. Significantly elevated in all BA-exposed groups. 2. Positively correlated with maternal BA intake. 3. Inversely correlated with fetal body weight at doses above the NOAEL.     

Ondansetron enhanced diclofenac‐induced nephrotoxicity in mice

This study was performed to investigate the effect of ondansetron, a serotonin receptor (5‐HT3) antagonist, in the alleviation of diclofenac‐induced kidney injuries. NMRI mice were randomly divided into six groups and treated with (A) untreated control group, (B) diclofenac (100 mg/kg), (C) ondansetron (1 mg/kg), (D to F) ondansetron (0.1, 0.5, and 1 mg/kg, respectively) and diclofenac (100 mg/kg) for last 3 days of experiment. The oxidative stress tests strongly demonstrated the negative synergistic effects of diclofenac and ondansetron, regarding the observation of dose‐dependent enhancement of malondialdehyde concentration, and reduction of glutathione content, and superoxide dismutase and catalase activity. Histopathological analyses revealed dose‐dependent tubular epithelial cells degeneration, outstanding mononuclear cells infiltration, clear necrosis at the papillary region of kidney, dilation, and vascular hyperemia in mice kidney tissues treated with ondansetron and diclofenac. Conclusively, these findings suggested the possible ondansetron‐diclofenac interaction through the induction of oxidative stress.     

Developmental toxicity evaluation of emodin in rats and mice

BACKGROUND: Emodin, a widely available herbal remedy, was evaluated for potential effects on pregnancy outcome. METHODS: Emodin was administered in feed to timed-mated Sprague-Dawley (CD) rats (0, 425, 850, and 1700 ppm; gestational day [GD] 6-20), and Swiss Albino (CD-1) mice (0, 600, 2500 or 6000 ppm; GD 6-17). Ingested dose was 0, 31, 57, and approximately 80-144 mg emodin/kg/day (rats) and 0, 94, 391, and 1005 mg emodin/kg/day (mice). Timed-mated animals (23-25/group) were monitored for body weight, feed/water consumption, and clinical signs. At termination (rats: GD 20; mice: GD 17), confirmed pregnant dams (21-25/group) were evaluated for clinical signs: body, liver, kidney, and gravid uterine weights, uterine contents, and number of corpora lutea. Fetuses were weighed, sexed, and examined for external, visceral, and skeletal malformations/variations. RESULTS: There were no maternal deaths. In rats, maternal body weight, weight gain during treatment, and corrected weight gain exhibited a decreasing trend. Maternal body weight gain during treatment was significantly reduced at the high dose. In mice, maternal body weight and weight gain was decreased at the high dose. CONCLUSIONS: Prenatal mortality, live litter size, fetal sex ratio, and morphological development were unaffected in both rats and mice. At the high dose, rat average fetal body weight per litter was unaffected, but was significantly reduced in mice. The rat maternal lowest observed adverse effect level (LOAEL) was 1700 ppm; the no observed adverse effect level (NOAEL) was 850 ppm. The rat developmental toxicity NOAEL was > or =1700 ppm. A LOAEL was not established. In mice, the maternal toxicity LOAEL was 6000 ppm and the NOAEL was 2500 ppm. The developmental toxicity LOAEL was 6000 ppm (reduced fetal body weight) and the NOAEL was 2500 ppm.     

Evaluation of Reproductive Disorders in Female Rats Exposed to N‐Methyl‐2‐Pyrrolidone

BACKGROUND: N‐methyl‐2‐pyrrolidone (NMP) is a solvent used in the petrochemical, and electronic industries, in pesticides production, veterinary drugs, and paint removers. The aim of study was to evaluate the relationship between the dose of NMP given orally and its effect on fertility in female rats and early development of their progeny. METHODS: Females were exposed by gavage 5 days/week to NMP at 150, 450, or 1000 mg/kg/day 2 weeks before mating, during mating, gestation, and lactation. On the first postnatal day (PND 1), the live and dead pups were counted, weighed, and gender was determined. On PND 4, the litters were culled to eight animals each and balanced for gender. Young animals were observed during 3 weeks after birth. RESULTS AND CONCLUSION: Fertility index did not significantly differ in the control and the group exposed at 150 mg/kg/day but it was significantly lower in the groups exposed at 450 or 1000 mg/kg/day. The number of live pups in the group exposed to the highest dose was significantly lower and the number of stillbirths in litters was significantly greater. Survival of the pups from all exposed groups during the 3 weeks after birth was significantly lower than the control animals. The results of our study indicate that intragastric exposure of female rats to NMP before pregnancy during gestation causes significant impairment in female fertility and intrauterine mortality rates. At lower doses, toxic or slightly toxic to the mothers, this substance causes decrease in viability and physical development of progeny.     

Maternal and developmental toxicity of low doses of cytosine arabinoside in mice

1-beta-D-Arabinofuranosylcytosine (Ara-C), an effective drug for the treatment of leukemia and breast cancer, was evaluated for developmental toxicity in pregnant Swiss mice. Ara-C was administered by intraperitoneal injection on gestational days 6-15 at doses of 0, 0.5, 2, and 8 mg/kg/day. Maternal observations included clinical signs, body weight change, food consumption, and gross evaluation of organs and uterine contents at necropsy (day 18). Live fetuses were examined for external, visceral, and skeletal alterations. Maternal toxicity was observed at 2 and 8 mg/kg/day, as evidenced by a significant decrease in body weight gain and food consumption during the treatment period. Significantly increased early and late resorptions and reduced number of live fetuses per liter as well as decreased fetal body weight were observed at 8 mg/kg/day. At 2 mg/kg/day, the incidence of cleft palate, renoureteral agenesis or hypoplasia, and poly- or oligodactyly was significantly increased, whereas fetal weight was reduced at 0.5 mg/kg/day. Thus, the developmental no-observed-adverse-effect-level (NOAEL) of Ara-C in the pregnant mouse is lower than 0.5 mg/kg/day, while the NOAEL for maternal toxicity is 0.5 mg/kg/day. We believe that exposure to this agent ought to be avoided during organogenesis.