Maternal Ethanol Research Articles

Effects of prenatal and postnatal exposure of rats to alcohol: Changes in (Na +K +) ATPase

Maternal ethanol consumption produces a reduction in postnatal growth. We have studied especially changes of liver and brain. This reduction is more marked if the alcoholic offspring are maintained with their biological mothers than if they are kept with surrogate mothers. Rats exposed prenatally to alcohol show a marked accumulation of fat in the liver and a significant proliferation of liver endoplasmic reticulum. No change in the postnatal development of liver alcohol (ADH) and acetaldehyde dehydrogenases (ALDH) (high and low K m) is observed in offspring from alcoholic mothers, with the exception of slightly higher ALDH (low K m) for the offspring that remain with alcoholic mothers. The postnatal development of the liver (Na +K +) ATPase is also similar in control and alcoholic groups. However, in the case of the enzyme from the brain, a lower ATPase activity is observed in the group derived from alcoholic mothers. Interestingly, at 20 days of postnatal period, an induction of the ATPase (from liver and brain) was observed when the group of offspring from alcoholic mothers were kept on an alcohol diet.

Inhibition of placental amino acid uptake in rats following acute and chronic ethanol exposure.

The effects of acute and chronic maternal ethanol consumption on in vitro placental uptake of alpha-aminoisobutyric acid (AIB), cycloleucine, L-alanine (Ala), L-leucine (Leu), and L-lysine (Lys) were determined. Ethanol (4 g/kg. po) administered 2 hr prior to sacrifice, reduced (p less than 0.05) placental villous net uptake of cycloleucine and Ala by 29%. Prior chronic ethanol consumption depressed (p less than 0.05) placental uptake of AIB (38%), cycloleucine (45%), Ala (35%), Leu (25%), and Lys (34%). In vitro exposure of previously untreated villous fragments for 2 hr to 2 mg/ml of ethanol reduced (p less than 0.05) the net uptake of AIB and cycloleucine by 24% and 31%, respectively, whereas the minimum concentration of acetaldehyde required to cause a significant inhibition was 310 microM for AIB and 465 microM for cycloleucine. Ethanol (3 mg/ml) had no effect on AIB or cycloleucine net uptake if sodium was omitted from the incubation media. The efflux of AIB (10(-6)M) and cycloleucine (10(-6)M) from villous tissue was unaffected (p less than 0.05) by either ethanol (3 mg/ml) or acetaldehyde (600 microM) and obeyed first order kinetics. It was concluded that acute, and especially chronic, maternal ethanol consumption can depress the placental uptake of a variety of amino acids in the rat and, in the acute setting, the effect was on a sodium-dependent system involved in amino acid influx into placental cells.

Maternal ethanol consumption and fetal development: two potential mechanisms.

Maternal ethanol consumption and fetal development: two potential mechanisms.

Maternal ethanol consumption and synaptic membrane glycoproteins in offspring.

The present study was undertaken to assess the influences of chronic maternal ethanol consumption, prior to and during gestation, on the development of synaptic plasma membranes (SPMs) and on the synthesis of SPM glycoproteins in offspring. Comparisons were made between animals whose mothers were pair-fed a control or 6.6% (v/v) ethanol liquid diet in which protein accounted for either 18% (original) (C & E) or 21% (revised) (*C & *E) of the calories. In addition, groups of pups that were either cross-fostered (*C & *E) with chow-fed surrogate mothers or reverse cross-fostered (offspring of chow-fed mothers with *C & *E mothers) were examined. Ethanol and matched (same dietary group) control pups had comparable brain and body weights, brain protein content, and yield of SPM proteins during the 10-24 day age period examined. However, the yield of SPM proteins from ethanol and control offspring of and/or reared by the three groups of rat mothers that received the *E and *C liquid diets was greater than that of the offspring of rats that were fed the original diets. This suggests that the original diets were not nutritionally adequate for pregnant rats. Despite the fact that the content of SPM proteins was comparable in ethanol and matched control pups, the offspring of ethanol-treated rats had an abnormal distribution of [3H]- or [14C]-fucose-derived radioactivity among SPM glycoproteins. The SPM abnormalities were most severe in the non-cross-fostered offspring of E rats. No SPM glycoprotein abnormalities were found in the reverse cross-fostered group. The results of the present study demonstrate that chronic maternal ethanol consumption prior to parturition has a severe effect on the synthesis of SPM glycoproteins in developing offspring without affecting the content of SPMs per se. It also demonstrates the importance of optimizing the composition of liquid diets used to feed pregnant rats.

Effects of maternal ethanol consumption in rats on basal and rhythmic pituitary - adrenal function in neonatal offspring

Neonatal corticoid treatment delays development of the circadian rhythm of plasma corticosterone in rats. We therefore sought to determine whether fetal or neonatal exposure to ethanol, a substance which activates the hypothalamo - pituitary - adrenal axis, produces similar effects. Subjects were the offspring of dams fed a 5.0% w/v ethanol-containing liquid diet or pair-fed an isocaloric control diet during gestation weeks two and three or during postnatal week one. At birth (day 1), the fetal ethanol-exposed pups had significantly higher brain and plasma corticosterone levels than the pair-fed or normal controls; brain and body weights were unaffected. By day 3, brain and plasma corticosterone titers in the fetal ethanol-exposed pups declined to the levels of the pair-fed and normal controls, although brain weights were significantly reduced. Significantly higher p.m. than a.m. levels of plasma corticosterone first occurred on day 18 both in the fetal ethanol-exposed pups and in the pair-fed and normal controls. Thus, despite its causing elevated corticosterone levels at birth, fetal exposure to ethanol did not affect the onset of the pituitary - adrenal circadian rhythm. On the other hand, exposure to ethanol during the first neonatal week delayed the onset of the pituitary - adrenal rhythm from day 18 to day 21. However, even greater delays occurred in the neonatal pair-fed controls, suggesting that the delays following neonatal exposure were due to nutritional deficits rather than to alcohol per se. The developmental and long-term influences of elevated corticoid levels at birth in fetal ethanol-exposed rats on other aspects of pituitary - adrenal function remain to be determined.

Effects of maternal ethanol intake during pregnancy on fetal and maternal liver enzyme systems in Wistar rats.

In the present study, the effects of maternal ethanol intake during pregnancy on microsomal cytochrome contents and on enzyme activities in the developing fetus were investigated. Ethanol intake to pregnant females did not affect the maternal body weight or number of fetuses, but tended to reduce the mean fetal body weight, especially the fetuses from a litter of mother who were treated with ethanol during day zero to 20 of gestation showed significant decreases in the body and liver weights. No significant changes were observed in the contents of cytochrome P-450 and b5 and the activities of NADPH-cytochrome c reductase and heme oxygenase in the livers of fetuses whose mothers were exposed to ethanol during pregnancy when compared with that of untreated pregnant rats. However, NADH-cytochrome b5 reductase activity in the fetal livers was found to significantly decrease by maternal ethanol intake during pregnancy.

Effects of maternal ethanol ingestion on cerebral neurotransmitters and cyclic-AMP in the rat offspring

1. 1. To study the effects of maternal alcohol ingestion on brain parameters in offspring, rats were given ethanol for drinking (25% w/v) from the time of mating until sacrifice. Controls drank tap water. 2. 2. Alcohol ingestion reduced daily food and liquid consumption but total caloric intake was only slightly diminished. 3. 3. Maternal body weight increased and offspring body weight, size and brain weight were reduced in the animals receiving alcohol. 4. 4. Brain concentrations of tryptophan, tyrosine and GABA were augmented in ethanol treated mothers at 1 day post-partum. 5. 5. Comparison of brain parameters in offspring of alcoholic mothers with those of controls showed that tryptophan and 5HT concentrations were augmented in 4 day old neonates, NA was increased in 21 day fetuses and 1 day old neonates, and adenylate cyclase activity was also greater in the brains of 21 day fetuses and the cerebellums of 4 day old neonates. 6. 6. Neither phosphodiesterase nor cyclic-AMP concentrations differed in offspring of alcoholic and control mothers. 7. 7. Data showed alterations in brain NA and 5HT systems in the offspring of alcoholic mothers.

Drunk Infant

The recent report of the Committee on Drugs on Naloxone use in Newborns1 did not consider its possible use for neonatal respiratory depression secondary to intrapartum maternal ethanol intoxication. It has been postulated that ethanol intoxication is mediated in part by an action on central opiate receptors,2 and naloxone has been used to reverse coma of adult ethanol intoxication.3 For the ethanol-intoxicated newborn, this may be one positive benefit of naloxone's actions on enkephalinor endorphin-mediated stress responses.4

Ethanol and psychotropic drug interaction during pregnancy and lactation

Prolonged maternal ethanol consumption for 8 days during pregnancy or for five days immediately after birth resulted in 30–46 per cent inhibition in the rate of chlorpromazine metabolism by the rat fetal and neonatal livers respectively. A significant increase in hepatic NADH/NAD and UDPG/ UDPGA ratios was observed in suckling neonatal and maternal livers from the ethanol-fed group. Acute administration of ethanol with chlorpromazine led to about 60 per cent inhibition of the metabolism of chlorpromazine. This inhibitory effect of ethanol on the metabolism of chlorpromazine was largely abolished by preincubation of liver homogenates with pyrazole (2 mM). Lactate (10 mM) addition to liver homogenates resulted in a significant inhibition of chlorpromazine metabolism. It is suggested that maternal ethanol consumption during preganancy and lactation inhibits the hepatic metabolism of drugs such as chlorpromazine which require glucuronidation for their detoxification. This ethanol-mediated inhibition is largely exerted through the decrease in the NAD-dependent conversion of UDP-glucose (UDPG) to UDP-glucuronic acid, (UDPGA).

Effects of acute ethanol exposure upon in vivo leucine uptake and protein synthesis in the fetal rat.

Tritiated L-leucine ((3H)L-leu) was injected into the amniotic sacs of 19-day gestation rat fetuses during a brief (4-hr) period of elevation in maternal serum ethanol. The pregnant rats received 47.5% ethanol at "high dose" (0.29 to 0.33 g/100 g body weight) or "low dose" (0.12 to 0.14 g/100 gm body weight) by intraperitoneal injection. Fetal brain and liver were removed and analyzed for tissue uptake (TU) and protein incorporation (PI) of (3H)L-leu. Relative protein synthesis, independent of alterations in TU, was expressed by the ratio PI/TU x 100. Delayed fetal effects of acute maternal ethanol exposure were studied by injecting the fetal amniotic sacs with (3H)L-leu 24 hr after maternal ethanol administration. Both TU and PI were decreased in high dose fetal brain. Liver PI, but not TU, was depressed. High dose ethanol treatment caused a reduction in protein synthesis (PI/TU x 100) in fetal brain but not liver. Low dose ethanol enhanced brain PI and both liver and brain PI/TU x 100. Utilization of (3H)L-leu was related to fourth-hour (sacrifice) maternal serum ethanol levels. Fetal brain was more strikingly affected than liver. Ethanol concentrations greater than 200 mg/dl caused a decrease in brain TU (control, 1879 +/- 185 versus ethanol, 1219 +/- 123 dpm/mg protein) and PI/TU x 100 (control, 48.9 +/- 3.3 versus ethanol, 31.5 +/- 2.9). At levels less than 100 mg/dl, PI/TU x 100 was enhanced in both brain (control, 48.9 +/- 3.3 versus ethanol, 67.3 +/- 2.8) and liver (control, 45.3 +/- 4.2 versus ethanol, 62.3 +/- 1.7). Tissue uptake of (3H)L-leu 24 hr after high dose maternal ethanol exposure was increased in fetal brain. The results support the hypothesis that a brief period of maternal/fetal ethanol exposure, similar to that found in "social" drinking humans, alters normal fetal metabolism.

Absence of a role for salsolinol in the mechanism of ethanol teratogenicity.

Alcohol and its primary metabolite, acetaldehyde, are central nervous system teratogens. Acetaldehyde can further interact with endogenous biogenic amines under certain conditions to generate tetrahydroisoquinoline (TIQ) alkaloidal metabolites, some of which interfere with adrenergic neuronal function and structural integrity. The possible role of salsolinol (the TIQ derived from the condensation of acetaldehyde with dopamine) in the mechanism of alcohol teratogenicity was investigated in rats. Administration of 2 mg/kg of salsolinol to rats on the 15th day of gestation did not result in the recovery of this TIQ in the fetuses. Furthermore, acute oral administration of alcohol (3 g/kg x 3 doses) to rats on different days of gestation did not result in the synthesis of salsolinol by the fetuses despite the high maternal blood ethanol levels (124 +/- 22 mg%). These findings argue against a role for salsolinol in the mechanism of alcohol teratogenicity. Small amounts of endogenous salsolinol (3.6 ng/g) were detected in fetuses from control rats, in agreement with previous findings in neonatal rats. The physiological role (if any) of endogenous salsolinol in the fetal and neonatal rat is not known.

Fetal 15-hydroxyprostaglandin dehydrogenase is altered by maternal ethanol exposure.

Several studies have suggested that ethanol consumption may alter prostaglandin metabolism and that this alteration may represent the molecular mechanism underlying certain of the pathophysiological consequences of chronic alcoholism. Our laboratory is investigating the hypothesis that ethanol induced changes in prostaglandin metabolism may be volved in the etiology of the condition termed fetal alcohol syndrome. In this study, pregnant rats (Holtzman) were exposed for 2 h each day throughout gestation to ethanol by vapor inhalation. Ethanol exposure resulted in retarded fetal growth and changes in the prostaglandin dehydrogenase activity in homogenates from placental amnion and maternal and fetal kidney.

Alterations in maternal and fetal prostaglandin dehydrogenase as a result of maternal ethanol consumption

Various lines of research have suggested that ethanol consumption may alter prostaglandin-related physiology. Our laboratory has reported that chronic exposure to high doses of ethanol lowers the ability of kidney and lung homogenates from male rats to catabolize prostaglandin E 2 and F 2α via 15-prostaglandin dehydrogenase (PGDH). Because of. the apparently unique role played by prostaglandins in conception, growth and development of the fetus and parturition, we have attempted to determine if the alterations observed in male rats also occur in females and if any alterations in fetal metabolism result from maternal ethanol exposure. Further, we have measured the influence of ethanol administration on renal clearance of the 15-keto metabolite of PGF 2α in an attempt to determine the in vivo significance of the enzyme inhibition observed in vitro . Initial results indicate the following. 1) Female Holtzman rats dosed at 2.0, 5.0 and 7.0 mg ethanol/kg during the first, second, and third trimesters of pregnancy, respectively, showed losses in renal PGDH activity similar to those found in males (1.52 versus 1.05 picomole/min/mg, p<0.001 by matched t-test). 2) Placental tissue (amnion) isolated from these same animals on day 21 of the pregnancies also showed a significant decrease in PGDH activity (14.79 versus 11.77 picomoles/min/ mg, p<0.01). 3) Kidney homogenates from fetuses delivered on day 21 of the pregnancies showed a significant increase in PGDH relative to pair-dosed controls (16.77 versus 12.65 picomoles/min/mg, p<0.01). 4) In a separate experiment, urinary clearance of PGF 2α metabolite was inhibited in a dose related manner up to a level of 6 gm/kg.

Effect of Ethanol and Ethanol‐Induced Hypothermia on Protein Synthesis in Pregnant and Fetal Rats

The effects of acute and chronic maternal ethanol intake and concomitant hypothermia on in vivo net protein synthesis in maternal and fetal tissues were investigated. No consistent effect on net protein synthesis was found in rats chronically exposed to ethanol if they were tested at a time when blood alcohol levels averaged 0.76 mg/ml and body temperatures were normal (38°C). If rats chronically exposed to ethanol were given ethanol acutely, which raised blood ethanol levels to 3 mg/ml and reduced maternal body temperature by 2.3°C, net protein synthesis was significantly (p &lt; 0.05) reduced in maternal brain and viscera, placenta, and in fetal brain and viscera. Acute ethanol exposure alone, yielding blood levels of 2.7 mg/ml and reducing maternal body temperature by over 2°C, also significantly (p &lt; 0.05) reduced net protein synthesis in the same tissues. In both groups of animals hypothermia was then eliminated to assess the effects of ethanol alone on protein synthesis. The etha‐nol‐induced hypothermia was found to be the major contributor to the observed depression in net protein synthesis in maternal brain and heart and in fetal brain. However, at high blood ethanol levels, ethanol directly, independent of hypothermia, also reduced net protein synthesis in maternal kidney, liver, and placenta, and in fetal heart, kidney, and liver. In conclusion, both ethanol‐induced hypothermia (to a major degree) and ethanol per se, at blood ethanol levels in excess of 1 mg/ml, depress net protein synthesis in vivo in rats.

Acute and chronic effects of maternal ethanol administration on the ovine maternal-fetal unit: J.C. Rose, J.W. Strandhoy and P.J. Meis. Departments of Physiology & Pharmacology and Obstetrics/Gynecology, Bowman Gray School of Medicine, Winston-Salem, NC 27103

The purpose of this study was to examine, in the pregnant ewe and its fetus, some of the physiological consequences of acute and chronic ethanol exposure. Ethanol was infused intravenously (2 g/kg/day over 2 h) to pregnant ewes from day 100 of pregnancy to term. Control animals received isocaloric infusions of 5% dextrose. Animals were pair-fed and allowed water ad lib. Maternal (n = 5) systolic, diastolic, and mean blood pressures and heart rate rose significantly by 1 h after starting ethanol, whereas fetal (n = 4) blood pressure and heart rate did not change during ethanol infusion. Maternal ethanol infusion produced a significant rise (p less than 0.01) in both fetal (n = 8) and maternal (n = 10) plasma cortisol levels. Peak blood ethanol concentration was significantly higher in the ewe (240 +/- 6 mg.dl-1, n = 7) than in the fetus (190 +/- 9 mg.dl-1, n = 6) at the end of the 2-hour infusion. Maternal rate of elimination after ethanol infusion was terminated was 40 mg.dl-1 per hour, while fetal elimination was 10 mg.dl-1 per hour. Body weights and crown-rump lengths of fetuses from 0.82 to 1.0 gestation were significantly less in ethanol-treated animals than in age-matched control animals. Fetal plasma thyroxine and triiodothyronine increments following thyrotrophin-releasing hormone administration were significantly less in alcohol-treated than in control animals. Thus, chronic exposure to ethanol during the latter part of gestation impaired fetal growth and altered fetal endocrine function in these animals.

Endocrine Effects of Maternal Alcoholization: Plasma and Brain Testosterone, Dihydrotestosterone, Estradiol, and Corticosterone

Maternal ethanol consumption was associated with reduced levels of dihydrotestosterone in the brains of 1--2-day-old male rats when compared to those of sex-matched pups obtained from dames that were fed sucrose. In contrast, brain levels of corticosterone were increased significantly in the pups of ethanol-fed animals when compared to those from sucrose-fed controls. Brain and plasma estradiol did not differ between groups. These results suggest that maternal ethanol consumption may influence the central nervous system and plasma levels of certain steroidal hormones in the offspring.

Ethanol induced changes of in vitro protein synthesis during the development and maturation of brain tissue.

Decreased protein synthesis in a cell free system of brain has been reported for male adult rats following chronic ethanol ingestion. To assess the developmental and maturational changes occurring in the neonatal brain, the effects of pre- and postnatal maternal ingestion of ethanol were determined. For these studies young female rats were given a 10% w/v ethanol/water solution for varying periods after impregnation and seven days post pregnancy. Data showed that maternal ethanol ingestion produced a large deficit in the in vitro incorporation of (14C) leucine into the hot TCA extractable residue of ribosomes of neonatal brain. Maximum inhibition was obtained when ethanol was given postnatally. To determine the molecular sites of ethanol's action, ribosomes and pH 5 enzymes from the adult and neonatal brain were examined. Data showed that the highest activity was obtained with control neonatal brain enzymes and ribosomal fractions.

Psychotropic drug metabolism in fetal alcohol syndrome.

Simultaneous intake of ethanol with chlorpromazine (thorazine), an antipsychotic drug, leads to about 60% decrease in the chlorpromazine removal from the rat blood. Studies with liver homogenates showed that ethanol inhibits the metabolism of this drug by about 50%. The inhibitory effect of ethanol on the metabolism of chlorpromazine can be largely abolished by pyrazole (2 mM) preincubation. Prolonged maternal ethanol consumption during pregnancy and lactation leads to a decrease in chlorpromazine metabolism in the fetal (30%), neonatal (46%) and maternal livers. Prolonged maternal ethanol intake also leads to an increase in the (UDPG)/(UDPGA) ratio in the suckling neonatal liver and the maternal liver. Simultaneous acute administration of ethanol (2g/kg) with psychotropic drugs such as chlordiazepoxide (librium), diazepam (valium), chlorpromazine (thorazine) or meprobamate (equanil) to pregnant or non-pregnant rats led to a decrease in the blood alcohol clearance rates. In another group of nonpsychotropic drugs tested, tolbutamide (orinase) produced the most pronounced (47%) decrease in blood alcohol clearance rates. This decrease was found to be accompanied by the inhibition of hepatic alcohol dehydrogenase.

Effect of maternal ethanol ingestion on serum growth hormone in the developing rat

Pregnant rats were kept on a liquid diet containing ethanol (6.8% v/v) from the 13th day of gestation and serum G H levels were determined in the offspring. In neonates exposed to ethanol throughout development, serum growth hormone (GH) secretion was initially increased and then declined to subnormal levels compared to controls. The levels returned to normal after weaning. Withdrawal from ethanol at birth produced similar alterations in serum GH concentrations to those seen in neonatal rats exposed to ethanol continuously. Postnatal exposure to ethanol alone also caused a decrease in GH concentration in rat pups. These data indicate that exposure to ethanol during gestation causes an alteration in the regulation of secretion of GH in the developing pups. A single dose of ethanol given to pups postnatally also caused a marked decline in serum GH levels demonstrating that in the developing pup ethanol can interfere acutely with GH release.

Effect of acute maternal ethanol exposure upon fetal development in the rat

Two studies on the effect of acute ethanol administration during Days 9-12 of gestation showed significant fetal weight reduction (6%-8%) in rats from ethanol-treated dams compared to water controls. Maternal weight gains could not account for the differences. These effects of acute doses (3-4 g ethanol/kg body weight), given only during organogenesis, suggest that chronic ethanol exposure during gestation is not required for some developmental retardation to occur. What effect this retardation may have upon subsequent behavioral development remains to be determined.