Low birthweight in rats induced by prenatal exposure to testosterone combined with alcohol, pair-feeding, or stress

Pregnant Sprague-Dawley dams were exposed to a liquid ethanol diet (35% ethanol-derived calories), an isocaloric pair-feeding regimen, restraint stress, or no treatment during the last week of pregnancy. Dams in each group received injections of testosterone propionate (TP) or the oil vehicle from days 15 through 20 of gestation. Birthweights of pups from dams administered TP and also exposed to alcohol, pair-feeding, or restraint stress were significantly depressed by as much as 40 percent compared to oil-injected counterparts. Prenatal exposure to alcohol, pair-feeding, or restraint stress in the absence of TP did not significantly depress birthweight, nor was birthweight depressed in animals from dams injected with TP but exposed to no other treatment. Results are discussed with respect to an inhibition of fetal growth produced by a possible synergism between activation of the hypothalamic-pituitary-adrenal axis and elevated androgen levels.     

Effect of high-fat diet during gestation, lactation, or postweaning on physiological and behavioral indexes in borderline hypertensive rats

Maternal obesity is becoming more prevalent. We used borderline hypertensive rats (BHR) to investigate whether a high-fat diet at different stages of development has adverse programming consequences on metabolic parameters and blood pressure. Wistar dams were fed a high- or low-fat diet for 6 wk before mating with spontaneously hypertensive males and during the ensuing pregnancy. At birth, litters were fostered to a dam from the same diet group as during gestation or to the alternate diet condition. Female offspring were weaned on either control or "junk food" diets until about 6 mo of age. Rats fed the high-fat junk food diet were hyperphagic relative to their chow-fed controls. The junk food-fed rats were significantly heavier and had greater fat pad mass than those rats maintained on chow alone. Importantly, those rats suckled by high-fat dams had heavier fat pads than those suckled by control diet dams. Fasting serum leptin and insulin levels differed as a function of the gestational, lactational, and postweaning diet histories. Rats gestated in, or suckled by high-fat dams, or maintained on the junk food diet were hyperleptinemic compared with their respective controls. Indirect blood pressure did not differ as a function of postweaning diet, but rats gestated in the high-fat dams had lower mean arterial blood pressures than those gestated in the control diet dams. The postweaning dietary history affected food-motivated behavior; junk food-fed rats earned less food pellets on fixed (FR) and progressive (PR) ratio cost schedules than chow-fed controls. In conclusion, the effects of maternal high-fat diet during gestation or lactation were mostly small and transient. The postweaning effects of junk food diet were evident on the majority of the parameters measured, including body weight, fat pad mass, serum leptin and insulin levels, and operant performance.     

“Green odor” inhalation by stressed rat dams reduces behavioral and neuroendocrine signs of prenatal stress in the offspring

Chronic maternal stress during pregnancy results in the “prenatally stressed” offspring displaying behavioral and neuroendocrine alterations that persist into adulthood. We investigated how inhalation of green odor (a mixture of equal amounts of trans-2-hexenal and cis-3-hexenol) by stressed dams might alter certain indices of prenatal stress in their offspring. These indices were depression-like behavior (increased immobility time in the forced-swim test) and acute restraint stress-induced changes in hypothalamo-pituitary-adrenocortical (HPA) axis activity [plasma corticosterone (CORT) and ACTH levels and the number of Fos-immunoreactive cells in the hypothalamic paraventricular nucleus (an index of neuronal activity)]. Pregnant rats were exposed to restraint stress for 60 min/day for 10 days (gestational days 10-19). The prenatally stressed offspring exhibited significant increases in depression-like behavior and in restraint stress-induced ACTH, CORT, and Fos responses, unless their dam had been exposed to green odor. The behavioral effect of the odor was also seen in offspring that were fostered by unstressed dams. The results obtained in the dams themselves were as follows. In vehicle-exposed stressed dams, but not in green odor-exposed ones, total body and adrenal weights were significantly decreased or increased, respectively. Depression-like behavior was not observed in the vehicle-exposed stressed dams themselves. Green odor inhalation prevented the impairment of maternal behavior induced by restraint stress. Thus, exposure of dams to stress may affect both the fetal brain and fetal HPA axis, and also maternal behavior, leading to altered behavioral and neuroendocrine responses in the offspring. Such effects may be prevented by the stressed dams inhaling green odor.     

Nucleic acid content and growth of fetal brain, liver and heart during inanition in pigs

Previous investigations have indicated that gilts deprived of dietary intake for periods up to 40 days are capable of maintaining pregnancy and producing offspring of normal body weight. The present experiment was designed to study the effects of inanition during middle or late pregnancy on growth and on protein and nucleic acid content of porcine fetal brain, liver and heart. Gilts were subjected to prolonged inanition (40 days; 0 kcal/day; water only) during either the middle third (Days 30-70, n = 3) or last third (Days 70-110, n = 3) of pregnancy; controls received a full diet (7028 kcal/day) until Day 70 (n = 3) or 110 (n = 3) when all dams were hysterectomized. Inanition during middle or late pregnancy had no detrimental effect on fetal brain development. Brain weight, cell size (protein/DNA ratio) and cell number (total DNA) were similar in all fetuses at Day 70 or 110. RNA concentrations at Days 70 and 110, protein concentration at Day 70 and total protein at Day 110 were higher in fetuses from starved dams than in those from controls, indicating greater protein synthetic activity in fetal brains from nutrient-deprived dams. Prolonged inanition during midpregnancy had only a limited effect on fetal liver and heart. Only liver RNA concentration and content at Day 70 differed in fetuses from starved dams; however, 40 days inanition during late gestation had marked detrimental effects. Liver weight, cell size and cell number were reduced in inanition as compared with controls by Day 110.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gestational Heat Stress Alters Postnatal Offspring Body Composition Indices and Metabolic Parameters in Pigs

The study objectives were to test the hypothesis that heat stress (HS) during gestational development alters postnatal growth, body composition, and biological response to HS conditions in pigs. To investigate this, 14 first parity crossbred gilts were exposed to one of four environmental treatments (TNTN, TNHS, HSTN, or HSHS) during gestation. TNTN and HSHS dams were exposed to thermal neutral (TN, cyclical 18–22°C) or HS conditions (cyclical 28–34°C) during the entire gestation, respectively. Dams assigned to HSTN and TNHS treatments were heat-stressed for the first or second half of gestation, respectively. Postnatal offspring were exposed to one of two thermal environments for an acute (24 h) or chronic (five weeks) duration in either constant TN (21°C) or HS (35°C) environment. Exposure to chronic HS during their growth phase resulted in decreased longissimus dorsi cross-sectional area (LDA) in offspring from HSHS and HSTN treated dams whereas LDA was larger in offspring from dams in TNTN and TNHS conditions. Irrespective of HS during prepubertal postnatal growth, pigs from dams that experienced HS during the first half of gestation (HSHS and HSTN) had increased (13.9%) subcutaneous fat thickness compared to pigs from dams exposed to TN conditions during the first half of gestation. This metabolic repartitioning towards increased fat deposition in pigs from dams heat-stressed during the first half of gestation was accompanied by elevated blood insulin concentrations (33%; P = 0.01). Together, these results demonstrate HS during the first half of gestation altered metabolic and body composition parameters during future development and in biological responses to a subsequent HS challenge.     

Serum concentrations of secretory IgA in pregnancies delivering at term or preterm.

Secretory component (SC) is a phospholipase A2 inhibitor possibly associated with pregnancy maintenance and in serum is bound either to IgA (sIgA) or IgM (sIgM). To determine if serum secretory component levels a) increase during pregnancy, b) fall as term approaches, c) are low in women who will deliver prematurely, serum sIgA was measured at "booking in" and related to weeks of gestation and length of gestation at subsequent noninduced delivery. Levels of sIgA increased during pregnancy; sIgA increased from a non-pregnant value of 1.6 nM +/- 0.2 (mean +/- SEM) to 2.8 nM +/- 0.3 at the end of the second trimester, then fell significantly between 31-34 weeks. Delivery before 37 weeks was associated with significantly reduced serum sIgA levels, particularly in women who delivered before 32 weeks and in whom sIgA concentrations were similar to those of nonpregnant women.     

Embryonic and calving losses in bovine mixed-breed twins induced by transfer of in vitro-produced embryos to bred recipients

One or two in vitro-produced (IVP) Japanese Black (JB) cattle embryos at 8 days after in vitro fertilization were transferred to the contralateral uterine horn of previously bred Japanese Shorthorn (JSH) or JSH-JB cross recipients, and then the occurrence of early embryonic death, abortion during mid- and late gestation, and calving loss were recorded. The survival rate of embryos, including indigenous ones, was not affected by the number of embryos transferred, and a significantly higher twinning rate (68% of pregnant recipients at 80 days after transfer) was achieved when two IVP embryos were transferred, as compared with the rate when one IVP embryo was transferred (24%). In late ET (recipients at 8.5-9.0 days after the onset of oestrus), the embryo survival rate (22%) and the pregnancy rate (42%) at 80 days after ET were significantly lower than those rates in the synchronous ET (recipients at 8.0 days after the onset of oestrus; 47 and 79%, respectively). In the early ET (recipients at 6.0-7.5 days after the onset of oestrus), no significant differences from the synchronous ET were detected in these rates. Twenty-six percent of twin pregnant recipients were aborted during mid- or late-pregnancy, and 39% of twin calves were stillborn. The mean gestation length of the twin-bearing JSH dams (276 days) was 1 week shorter than that of the single-bearing JSH dams, and it was 2 weeks shorter than that of the JB dams bearing a single JB calf derived from the IVP embryos. The longer gestation length of single JB calves derived from IVP embryos resulted in a significantly higher mean birth weight than that of in vivo control calves with the standard length of gestation. In conclusion, the number of embryos to be transferred did not affect the embryo survival rate, and the transfer of two IVP embryos to previously inseminated recipients induced a significantly higher twinning rate during early pregnancy than that of one IVP embryo transfer. The incidence of embryonic losses during early pregnancy increased when Day 8 embryos were transferred to the recipients later in the oestrous cycle (>8.0 days). The results suggested that one cause of the high rate of abortions and stillbirths in twin-bearing dams is the difference in the mean gestation length between the native JSH and JB foetuses derived from transferred IVP embryos.     

Prevalence of rat virus infection in progeny of acutely or persistently infected pregnant rats

Infant rats are susceptible to persistent rat virus (RV) infection, but risk of persistent infection after prenatal exposure to virus is unclear. We examined this aspect of RV infection in the progeny of dams inoculated with virus during or prior to pregnancy. Sprague-Dawley (SD) dams were infected during pregnancy (gestation day 9) by oronasal inoculation with 10(5) TCID50 of the UMass strain of RV. SD rats were infected prior to pregnancy by oronasal inoculation of two-day-old females with 10(2) TCID50 of RV-UMass, which induced persistent infection. They were mated to non-immune males after reaching sexual maturity. Rats were assessed for RV infection by virus isolation, in situ hybridization, contact transmission, or serologic testing. The progeny of dams inoculated with virus during gestation had high prevalence of infection through postpartum week 9 (9 of 12 rats were virus positive at week 3, and 7 of 10 were virus positive at week 9). Additionally, 2 of 10 rats were virus positive at least through postpartum week 15. The progeny from persistently infected, seropositive dams had no evidence of infection and did not transmit infection to contact sentinels. However, 12 dams were virus positive at necropsy and 9 had transmitted infection to their breeding partners. These results indicate that prenatal infection in non-immune dams can lead to RV persistence in their progeny. By contrast, the progeny of persistently infected dams are protected from infection, presumably by maternal antibody, although their dams can transmit infection to their breeding partners.     

Role of TNF-alpha in prenatal alterations in dams of mice under thermal stress

The possible involvement of cytokines such as tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interferon-gamma (IFN-gamma) that are suspected of causing pregnancy loss and miscarriage has been investigated in dams of mice subjected to hyperthermia. Thermal stress was induced by exposing mice dams at 40+/-2 degrees C for 4 h every day during the different phases of the gestation period whereas the normothermic animals were housed at 22+/-2 degrees C. The effect of maternal thermal stress was measured in pregnant mice at different phases of the gestation period namely, blastogenesis-implantation phase (days 0-5 postconceptionem [p.c.]), organogenesis or embryogenesis phase (days 6-15 p.c.) and fetogenesis phase (days 16-20 p.c.). Uterine examination of dams subjected to hyperthermia on days 6-15 p.c. showed maximum reduction in live fetus number, gestational index and maximum pre and postimplantation loss in comparison with dams housed in normothermic environment and dams exposed to thermal stress between days 0-5 and 16-20 p.c. Maximum resorption rate and number of non-viable fetuses were observed in dams exposed to hyperthermia during days 6-15 p.c. Elevated levels of TNF-alpha and IL-1 beta were observed in the amniotic fluid of dams subjected to hyperthermia during days 6-15 p.c. but IFN-gamma levels remained unaltered. Single intraperitoneal (i.p.) administration of recombinant mouse TNF-alpha at a dose of 1 and 0.5 ng/mice in dams on day 6 in normothermic condition resulted in a reduced number of live fetuses. Administration of anti-TNF-alpha antibody i.p. at a dose of 10 microg/dam on day 6 p.c. and subjected to thermal stress between days 6-15 p.c. increased marginally the number of fetuses but failed to attain statistical significance in comparison with days 6-15 p.c. thermally stressed dams without antibody treatment. It is concluded that the induction of TNF-alpha, in the amniotic fluid is associated with thermal stress during pregnancy and may be linked to the reproductive performances of dams. This study will help in understanding the mechanism of thermal injury in pregnant subjects.     

High-protein diet during gestation and lactation affects mammary gland mRNA abundance, milk composition and pre-weaning litter growth in mice

We evaluated the effect of a high-protein diet (HP) on pregnancy, lactational and rearing success in mice. At the time of mating, females were randomly assigned to isoenergetic diets with HP (40% w/w) or control protein levels (C; 20%). After parturition, half of the dams were fed the other diet throughout lactation resulting in four dietary groups: CC (C diet during gestation and lactation), CHP (C diet during gestation and HP diet during lactation), HPC (HP diet during gestation and C diet during lactation) and HPHP (HP diet during gestation and lactation). Maternal and offspring body mass was monitored. Measurements of maternal mammary gland (MG), kidney and abdominal fat pad masses, MG histology and MG mRNA abundance, as well as milk composition were taken at selected time points. HP diet decreased abdominal fat and increased kidney mass of lactating dams. Litter mass at birth was lower in HP than in C dams (14.8 v. 16.8 g). Dams fed an HP diet during lactation showed 5% less food intake (10.4 v. 10.9 g/day) and lower body and MG mass. On day 14 of lactation, the proportion of MG parenchyma was lower in dams fed an HP diet during gestation as compared to dams fed a C diet (64.8% v. 75.8%). Abundance of MG α-lactalbumin, β-casein, whey acidic protein, xanthine oxidoreductase mRNA at mid-lactation was decreased in all groups receiving an HP diet either during gestation and/or lactation. Milk lactose content was lower in dams fed an HP diet during lactation compared to dams fed a C diet (1.6% v. 2.0%). On days 14, 18 and 21 of lactation total litter mass was lower in litters of dams fed an HP diet during lactation, and the pups' relative kidney mass was greater than in litters suckled by dams receiving a C diet. These findings indicate that excess protein intake in reproducing mice has adverse effects on offspring early in their postnatal growth as a consequence of impaired lactational function.     

The food intake of rats during pregnancy and lactation

Quantities of food required by Sprague-Dawley rats during gestation and lactation and in the post-lactation period were examined. Rats allowed to eat ad libitum during pregnancy consumed quantities of food only slightly greater than the amount reported to be the average intake of pregnant Sprague-Dawley rats (20 g/day). Rats delivered their pups on day 22 or day 23 of the gestation period, but regardless of the day of delivery, the food intake of each rat decreased on day 21 of pregnancy and then decreased a second time on the day of parturition. During lactation, food consumption of the rats soon exceeded the amount reported as the average intake of lactating rats (30-35 g/day). Food intake was found to escalate from 12.2 +/- 3.1 g/rat on day 0 of lactation, the lowest intake in the study, to 94.4 +/- 23.7 g on day 21 of lactation. However, in the latter part of the lactation period, the intake represented the combined food intake of dams and pups. Eight days in the post-lactation period were required for food intake of dams to return to a level near that recorded at the beginning of pregnancy.     

Energy allocation during concurrent pregnancy and lactation in Norway rats with delayed and undelayed implantation

Despite the high cost of lactation alone, concurrent pregnancy and lactation (CPL) is widespread among rodents. Many species that exhibit CPL delay implantation of the litter in utero while nursing. The first purpose of this study was to describe the pattern of energy allocation during CPL in a species with a large degree of overlap between gestation and lactation. Resting metabolic rate, food consumption and mass changes of Norway rat dams and litters, digestive efficiency and urinary energy loss of dams, and pup tissue energy equivalents were determined for CPL dams and for dams that were only lactating (C). CPL dams had significantly higher metabolic rates than C dams. Food consumption, pup growth, tissue energy equivalents, and assimilation efficiency were similar for both groups. The energy equivalent of mass change was greater for C dams, which gained in maternal mass (lipid) during lactation, than for CPL dams, which only increased in mass because of the litter in utero. The second purpose of this study was to investigate the suggestion that delayed implantation during CPL evolved as a mechanism to lower peak energy demands during CPL. Concurrently pregnant and lactating dams were injected with estrone (ECPL dams) on days 3-16 of lactation to prevent them from delaying implantation. A group of dams that were only lactating also received estrone injections (EC dams). ECPL dams produced smaller offspring at weaning than EC dams.(ABSTRACT TRUNCATED AT 250 WORDS)     

Melatonin supplementation alters uteroplacental hemodynamics and fetal development in an ovine model of intrauterine growth restriction

Using a mid- to late-gestation ovine model of intrauterine growth restriction (IUGR), we examined uteroplacental blood flow and fetal growth during melatonin supplementation as a 2 × 2 factorial design. At day 50 of gestation, 32 ewes were supplemented with 5 mg of melatonin (MEL) or no melatonin (CON) and were allocated to receive 100% [adequate; (ADQ)] or 60% [restricted (RES)] of nutrient requirements until day 130 of gestation. Umbilical artery blood flow was increased from day 60 to day 110 of gestation in MEL vs. CON dams, while umbilical artery blood flow was decreased from day 80 to day 110 of gestation in RES vs. ADQ dams. At day 130 of gestation, uteroplacental hemodynamics, measured under general anesthesia, and fetal growth were evaluated. Uterine artery blood flow was decreased in RES vs. ADQ dams, while melatonin supplementation did not affect uterine artery blood flow. Total placentome weight and placentome number were not different between treatment groups. Fetal weight was decreased by nutrient restriction. Abdominal girth and ponderal index were increased in fetuses from MEL-ADQ dams vs. all other groups. Fetal biparietal distance was decreased in CON-RES vs. CON-ADQ dams, while melatonin supplementation rescued fetal biparietal distance. Fetal kidney length and width were increased by maternal melatonin treatment. Fetal cardiomyocyte area was altered by both maternal melatonin treatment and nutritional plane. In summary, melatonin may negate the consequences of IUGR during specific abnormalities in umbilical blood flow as long as sufficient uterine blood perfusion is maintained during pregnancy.     

Prenatal stress alters seizure thresholds and the development of kindled seizures in infant and adult rats

Stressful events during gestation and in the neonatal period have important effects on the later physical and mental health of the offspring. The present study tested the hypothesis that pre- and/or postnatal stress would affect seizure susceptibility in infant and adult rats, using the hippocampal kindling model. Prenatal stress consisted of daily restraint of the dam under bright light (for 45 min, 3 x / day) during either early gestation or mid/late gestation. Pups were compared to pups born to unstressed dams. Postnatal stress (administered on Days 4 and 5 after birth) consisted of either separation from the dam and placement in the bedding of a strange male for 1 h or injection of dexamethasone. Pups were compared to nonstressed siblings of the same litter. Both early and mid/late-gestation prenatal stress significantly lowered the after-discharge threshold (ADT) in infant, 14-day-old rat offspring, as compared to nonstressed control offspring. This effect on ADT was lost by adulthood. Mid/late-gestation stress increased the rate of kindled seizure development in infant rats and in their adult male, but not female, siblings. Postnatal stress had no significant effect on ADT or kindling rate. These findings indicate that prenatal stress, particularly during the latter half of pregnancy, may play an important role in increasing seizure vulnerability in the unborn offspring. These effects are more pronounced in infancy, but can also extend to adulthood.     

Pregnancy-induced changes in ultradian rhythms persist in circadian arrhythmic Siberian hamsters

The impact of pregnancy and lactation on ultradian rhythms (URs) and circadian rhythms (CRs) of locomotor activity was assessed in circadian rhythmic and arrhythmic Siberian hamsters maintained in a long-day photoperiod (16 h light/day). Progressive decrements in CR robustness and amplitude over the course of gestation were accompanied by enhanced URs. Dark-phase UR period and amplitude increased during early gestation and complexity and robustness increased during late gestation. The persistence of pregnancy-associated enhancements of URs in circadian arrhythmic (ARR) hamsters suggests that reproductive modulation of the UR waveform is not dependent on coherent circadian organization. The increased incidence of dark-phase URs appeared more rapidly in ARR dams than entrained (ENTR) dams. Throughout gestation, the percentage of dams with dark-phase URs was significantly greater in the ARR group. Gestational increases in UR complexity and robustness emerged earlier and were greater in ARR than ENTR dams. The attenuation of CRs during lactation is correlated with increased expression of URs. Relaxation of circadian control of the dam's behavior may increase fitness by permitting more efficient interactions with circadian arrhythmic pups.     

Marginal Zinc Deficiency in Pregnant Rats Impairs Bone Matrix Formation and Bone Mineralization in Their Neonates

Zinc (Zn) deficiency during pregnancy may result in a variety of defects in the offspring. We evaluated the influence of marginal Zn deficiency during pregnancy on neonatal bone status. Nine-week-old male Sprague-Dawley rats were divided into two groups and fed AIN-93G-based experimental diets containing 35 mg Zn/kg (Zn adequately supplied, N) or 7 mg Zn/kg (low level of Zn, L) from 14-day preconception to 20 days of gestation, that is, 1 day before normal delivery. Neonates were delivered by cesarean section. Litter size and neonate weight were not different between the two groups. However, in the L-diet-fed dam group, bone matrix formation in isolated neonatal calvaria culture was clearly impaired and was not recovered by the addition of Zn into the culture media. Additionally, serum concentration of osteocalcin, as a bone formation parameter, was lower in neonates from the L-diet-fed dam group. Impaired bone mineralization was observed with a significantly lower content of phosphorus in neonate femurs from L-diet-fed dams compared with those from N-diet-fed dams. Moreover, Zn content in the femur and calvaria of neonates from the L-diet group was lower than that of the N-diet-fed group. In the marginally Zn-deficient dams, femoral Zn content, serum concentrations of Zn, and osteocalcin were reduced when compared with control dams. We conclude that maternal Zn deficiency causes impairment of bone matrix formation and bone mineralization in neonates, implying the importance of Zn intake during pregnancy for proper bone development of offspring.     

Effects of folic acid and amino acids supplementation on zinc intestinal absorption in the progeny of ethanol-treated rats

This study was designed to examine the effects of supplementation with folic acid and amino acids in dams that consumed ethanol during gestation and lactation to see whether there is an improvement in the intestinal absorption of zinc in pup rats on the 21st day after birth. The rats were randomized into two groups: Ethanol-rats (EG) were administered ethanol during the pregnancy and lactation periods; the ethanol-folic acid group (EFG) received a folic acid and amino acid supplement concomitantly with ethanol administration during pregnancy and lactation. The dams were mated to obtain the first offspring. Two sets of experiments were performed on the offspring at 21 days after birth. In general, in the first set, jejunal zinc absorption in the offspring of EG and EFG groups showed a gradual increase along with increased perfusion time at all assayed concentrations. Jejunal zinc absorption expressed as nmol/intestinal surface was higher in the ethanol-folic acid group than in ethanol animals at all assayed concentrations except at 25 microM concentration. In the second set of experiments, distal ileum zinc absorption in the offspring of ethanolfolic acid dams showed a significant increase at all concentrations tested. These results indicate that supplementation of folic acid and amino acids to dams that consume ethanol during gestation and lactation increase serum and milk zinc levels, although the zinc ingestion is lower. In pups of the supplemented dams, the jejunal and ileal absorption of zinc increased; as a consequence, the serum zinc levels increased. The activity of alcohol dehydrogenase, a metaloenzyme dependent on zinc levels, also increased.     

Chronic ingestion of ethanol or glucose solutions affects hypothalamic and limbic TRH metabolism in dams and their pups

The effect of chronic ethanol consumption during pregnancy and lactation on thyrotropin releasing hormone (TRH) metabolism was investigated in the hypothalamus and limbic areas of female rats and their weaned pups. Pregnant female rats received ethanol or isocaloric glucose solution during pregnancy either alone, or also during the 3 weeks of lactation. Thyrotropin (TSH) and corticosterone levels were measured in serum; TRH and TRH-gly concentrations were determined in hypothalamus, hippocampus, n.accumbens, frontal cortex and amygdala of dams and pups at 21 days after parturition. Ethanol or glucose consumption during pregnancy and lactation produced a decrease in TSH levels compared with control animals fed at libitum; water replacement during lactation normalized TSH levels only in glucose-fed dams. Pups from ethanol or pair-fed dams showed low weight and increased TSH levels compared with normal rats. Variations in TRH metabolism were detected in limbic areas. Chronic ethanol caused a decrease in the levels of TRH in the hippocampus and frontal cortex of dams. In contrast, glucose chronic ingestion increased TRH content specifically in n.accumbens and amygdala of dams. Most of the variations in TRH content of limbic areas of pups were not specific for glucose or ethanol treatment and correlated with the deleterious effect of the mother's thyroid condition, although some differences were observed depending on pup's gender. These results support the involvement of TRHergic neurons in the limbic system of the female rat exposed to alcohol or glucose during pregnancy and lactation.     

The impact of prenatal circadian rhythm disruption on pregnancy outcomes and long-term metabolic health of mice progeny

Animal studies demonstrate that circadian rhythm disruption during pregnancy can be deleterious to reproductive capacity and the long-term health of the progeny. Our previous studies in rats have shown that exposure of pregnant dams to an environment that significantly disrupts maternal circadian rhythms programs increased adiposity and poor glucose metabolism in offspring. In this study, we used mice with a ClockΔ19 mutation to determine whether foetal development within a genetically disrupted circadian environment affects pregnancy outcomes and alters the metabolic health of offspring. Ten female ClockΔ19+MEL mutant mice were mated with 10 wildtype males, and 10 wildtype females were mated with 10 ClockΔ19+MEL mutant males. While genetically identical, the heterozygote foetuses were exposed to either a normal (wildtype dams) or disrupted (ClockΔ19+MEL mutant dams) circadian environment during gestation. Pregnancy outcomes including time to mate, gestation length, litter size and birth weight were assessed. One male and one female offspring from each litter were assessed for postnatal growth, body composition, intraperitoneal glucose tolerance test and intraperitoneal insulin tolerance test at 3 and 12 months of age. There was no effect of maternal genotype on pregnancy outcomes, with days to plug, gestation length, litter size and perinatal mortality not significantly different between wildtype and ClockΔ19+MEL mutant dams. Similarly, there was no effect of maternal genotype on weight of the offspring at birth or at any stage of postnatal growth. While there was an effect of sex on various tissue weights at 3 and 12 months of age, there were minimal effects of maternal genotype. Relative adrenal weight was significantly reduced (?32%) in offspring from ClockΔ19+MEL mutant dams, whereas gastrocnemius muscle was significantly increased (+16%) at 3 months of age only. Intraperitoneal glucose tolerance tests at 3 months of age revealed female offspring from ClockΔ19+MEL mutant dams had significantly reduced area under the curve following glucose administration (?25%), although no differences were found at 12 months of age. There was no effect of maternal genotype on intraperitoneal insulin tolerance at 3 or 12 months of age for either sex. These results demonstrate that foetal growth within a genetically disrupted circadian environment during gestation has no effect on pregnancy success, and only marginal impacts upon the long-term metabolic health of offspring. These results do not support the hypothesis that circadian rhythm disruption during pregnancy programs poor metabolic homeostasis in offspring. However, when maintained on a 12L:12D photoperiod, the ClockΔ19+MEL mutant dams display relatively normal patterns of activity and melatonin secretion, which may have reduced the impact of the mutation upon foetal metabolic programming.     

Effect of restraint stress on plasma concentrations of cortisol, progesterone and pregnancy associated-glycoprotein-1 in pregnant heifers during late embryonic development

The aim of the present study was to evaluate the effect of restraint stress, which is commonly practised in the field, on plasma concentrations of cortisol, progesterone (P4) and bovine pregnancy-associated glycoprotein-1 (boPAG-1) in pregnant heifers between Days 30 to 40 of gestation. Twelve Holstein-Friesian heifers between Days 30 (Day 0 of experiment) and 40 (Day 10 of experiment) of pregnancy in a Hungarian dairy farm were used in the present study. The heifers were exposed to an acute stressor consisting of immobilisation (restraint stress) in a crush for 2 h (Group 1, n = 6) on Day 2 (Hour 48) and for 2 × 2 h (Group 2, n = 6) on Days 2 and 3 (Hour 72) of the experiment.Transrectal ultrasonography (7.5 MHz linear-array rectal transducer) was performed daily from Day 0 to Day 10 of the experiment to detect embryonic heartbeat or the fate of the conceptus. Blood samples were withdrawn before each ultrasonographic examination. Additional blood samples were withdrawn by 1 and 2 h (at Hours 49 and 50 in Groups 1 and 2 and Hours 73 and 74 in Group 2) of the onset of applying the stressor. Plasma cortisol, P4 and boPAG-1 concentrations were measured by radioimmunoassay. Acute restraint stress significantly (P < 0.001) increased the plasma cortisol level in pregnant heifers at 1 h of the exposure to the stressor at Days 2 (48 h) and 3 (72 h) of the experiment. On the other hand, the restraint stress did not affect the concentration of P4 and boPAG-1 concentrations in both groups. In conclusion, restraint stress for 2 h during early pregnancy in heifers increased blood cortisol, but it did not affect the concentrations of P4 and boPAG-1 between Days 30 to 40 of gestation.