Lack of prenatal testosterone surge in fetal rats exposed to alcohol: alterations in testicular morphology and physiology

Kiss1-dependent and independent release of luteinizing hormone and testosterone in perinatal male rats

Prenatal and postnatal biphasic increases in plasma testosterone levels derived from perinatal testes are considered critical for defeminizing/masculinizing the brain mechanism that regulates sexual behavior in male rats. Hypothalamic kisspeptin neurons are indispensable for stimulating GnRH and downstream gonadotropin, as well as the consequent testicular testosterone production/release in adult male rats. However, it is unclear whether kisspeptin is responsible for the increase in plasma testosterone levels in perinatal male rats. The present study aimed to investigate the role of Kiss1/kisspeptin in generating perinatal plasma LH and the consequent testosterone increase in male rats by comparing the plasma testosterone and LH profiles of wild-type (Kiss1^+/+) and Kiss1 knockout (Kiss1^-/-) male rats. A biphasic pattern of plasma testosterone levels, with peaks in the prenatal and postnatal periods, was found in both Kiss1^+/+ and Kiss1^-/- male rats. Postnatal plasma testosterone and LH levels were significantly lower in Kiss1^-/- male rats than in Kiss1^+/+ male rats, whereas the levels in the prenatal embryonic period were comparable between the genotypes. Exogenous kisspeptin challenge significantly increased plasma testosterone and LH levels and the number of c-Fos-immunoreactive GnRH neurons in neonatal Kiss1^-/- and Kiss1^+/+ male rats. Kiss1 and Gpr54 (kisspeptin receptor gene) were found in the testes of neonatal rats, but kisspeptin treatment failed to stimulate testosterone release in the cultured testes of both genotypes. These findings suggest that postnatal, but not prenatal, testosterone increase in male rats is mainly induced by central kisspeptin-dependent stimulation of GnRH and consequent LH release.

Sex Differences in Acute Neuroendocrine Responses to Stressors in Rodents and Humans

Sex differences in the neuroendocrine response to acute stress occur in both animals and humans. In rodents, stressors such as restraint and novelty induce a greater activation of the hypothalamic-pituitary-adrenal axis (HPA) in females compared to males. The nature of this difference arises from steroid actions during development (organizational effects) and adulthood (activational effects). Androgens decrease HPA stress responsivity to acute stress, while estradiol increases it. Androgenic down-regulation of HPA responsiveness is mediated by the binding of testosterone (T) and dihydrotestosterone (DHT) to the androgen receptor, as well as the binding of the DHT metabolite, 3β-diol, to the β form of the estrogen receptor (ERβ). Estradiol binding to the α form of the estrogen receptor (ERα) increases HPA responsivity. Studies of human sex differences are relatively few and generally employ a psychosocial paradigm to measure stress-related HPA activation. Men consistently show greater HPA reactivity than women when being evaluated for achievement. Some studies have found greater reactivity in women when being evaluated for social performance. The pattern is inconsistent with rodent studies but may involve the differential nature of the stressors employed. Psychosocial stress is nonphysical and invokes a significant degree of top-down processing that is not easily comparable to the types of stressors employed in rodents. Gender identity may also be a factor based on recent work showing that it influences the neural processing of positive and negative emotional stimuli independent of genetic sex. Comparing different types of stressors and how they interact with gender identity and genetic sex will provide a better understanding of sex steroid influences on stress-related HPA reactivity.

A pilot study on the effect of early provision of dietary docosahexaenoic acid on testis development, functions, and sperm quality in rats exposed to prenatal ethanol

BACKGROUND

Prenatal ethanol (EtOH) exposure is associated with adverse effect on the male reproductive function. Dietary docosahexaenoic acid (DHA) is known to improve testis function and sperm parameters, thereby male fertility. This study piloted whether dietary DHA influences testis development and function in rats exposed to prenatal EtOH.

METHODS

Pregnant female Sprague-Dawley rats (n = 30) received either EtOH (3 g/kg, twice a day, n = 14) or dextrose (n = 16) throughout pregnancy. Moreover, they were fed either diet supplemented with (Cont + DHA, n = 8, EtOH + DHA, n = 6) or without DHA (1.4% w/w of total fatty acids) (Cont, EtOH, n = 8 each), with pups being continued on their mothers' diet after weaning. Tissues were collected at gestational day (GD) 20, postnatal day (PD) 4, 21, 49 and 90 for analyzing testicular developmental markers and sperm parameters, and plasma for testosterone.

RESULTS

Dietary DHA increased serum testosterone at GD20 (p < .05) and sperm normal morphology at PD90 (p < .0001) compared to the group without DHA supplementation. Dietary DHA also increased the height of germinal epithelium at peripuberty, PD49 (p < .03). The EtOH exposure induced a marked decline in the testicular gene expression of StAR at PD49 (p < .02) than those of non-EtOH treated group.

CONCLUSIONS

These findings indicate that dietary DHA may positively contribute to male fertility by impacting sperm normal morphology likely by increasing fetal testosterone level. Prenatal EtOH exposure did not adversely affect the overall testis developmental markers during development and sperm parameters in adulthood.

Adverse reproductive outcomes associated with fetal alcohol exposure: a systematic review

Fetal alcohol exposure results in well-characterised neurobehavioural deficits in offspring, which form the basis for diagnosing fetal alcohol spectrum disorder. However, there is increasing interest in the full range of health complications that can arise in children and adults with this disorder. We used a systematic review approach to locate all clinical and preclinical studies across a broad range of health outcomes in offspring exposed to prenatal alcohol. Our search encompassed four databases (PubMed, CINAHL, EMBASE and Web of Science) and titles/abstracts from retrieved studies were screened against strict inclusion/exclusion criteria. This review specifically evaluated studies reporting on reproductive outcomes in both males and females. A total of 23 studies were included, 5 clinical and 18 preclinical. Although there was a wide range in the quality of reporting across both clinical and preclinical studies, and variable results, trends emerged amongst the reproductive measures that were investigated. In females, most studies focussed on age at first menarche/puberty onset, with evidence for a significant delay in alcohol-exposed offspring. In males, offspring exposed to prenatal alcohol had altered testosterone levels, reduced testes and accessory gland weights and reduced sperm concentration and semen volume. However, further studies are required due to the paucity of clinical studies, the narrow scope of female reproductive outcomes examined and inconsistencies in outcomes across preclinical studies. We recommend that adolescents and individuals of reproductive age diagnosed with f-etal alcohol spectrum disorder be assessed for reproductive dysfunction to allow appropriate management of their reproductive health and fertility.

Sex Differences in Early Postnatal Microglial Colonization of the Developing Rat Hippocampus Following a Single-Day Alcohol Exposure

Microglia are involved in various homeostatic processes in the brain, including phagocytosis, apoptosis, and synaptic pruning. Sex differences in microglia colonization of the developing brain have been reported, but have not been established following alcohol insult. Developmental alcohol exposure represents a neuroimmune challenge that may contribute to cognitive dysfunction prevalent in humans with Fetal Alcohol Spectrum Disorders (FASD) and in rodent models of FASD. Most studies have investigated neuroimmune activation following adult alcohol exposure or following multiple exposures. The current study uses a single day binge alcohol exposure model (postnatal day [PD] 4) to examine sex differences in the neuroimmune response in the developing rat hippocampus on PD5 and 8. The neuroimmune response was evaluated through measurement of microglial number and cytokine gene expression at both time points. Male pups had higher microglial number compared to females in many hippocampal subregions on PD5, but this difference disappeared by PD8, unless exposed to alcohol. Expression of pro-inflammatory marker CD11b was higher on PD5 in alcohol-exposed (AE) females compared to AE males. After alcohol exposure, C-C motif chemokine ligand 4 (CCL4) was significantly increased in female AE pups on PD5 and PD8. Tumor necrosis factor-α (TNF-α) levels were also upregulated by AE in males on PD8. The results demonstrate a clear difference between the male and female neuroimmune response to an AE challenge, which also occurs in a time-dependent manner. These findings are significant as they add to our knowledge of specific sex-dependent effects of alcohol exposure on microglia within the developing brain.

Sex differences in associations between white matter microstructure and gonadal hormones in children and adolescents with prenatal alcohol exposure

Despite accumulating evidence from animal models demonstrating that prenatal alcohol exposure (PAE) results in life-long neuroendocrine dysregulation, very little is known on this topic among humans with fetal alcohol spectrum disorders (FASD). We expected that alterations in gonadal hormones might interfere with the typical development of white matter (WM) myelination, and in a sex-dependent manner, in human adolescents with FASD. In order to investigate this hypothesis, we used diffusion tensor imaging (DTI) to assess: 1) whether or not sex moderates the impact of PAE on WM microstructure; and 2) how gonadal hormones relate to alterations in WM microstructure in children and adolescents affected by PAE.

METHODS

61 youth (9 to 16 yrs.; 49% girls; 50% PAE) participated as part of the Collaborative Initiative on Fetal Alcohol Spectrum Disorders (CIFASD). DTI scans and passive drool samples were obtained to examine neurodevelopmental associations with testosterone (T) and dehydroepiandrosterone (DHEA) levels in boys and girls, and estradiol (E2) and progesterone (P) levels in girls. Tract-based spatial statistics were utilized to generate fractional anisotropy (FA) and mean diffusivity (MD) for 9 a priori WM regions of interest (ROIs).

RESULTS

As predicted, alterations in FA were observed in adolescents with PAE relative to controls, and these differences varied by sex. Girls with PAE exhibited lower FA (Inferior fronto-occipital and Uncinate fasciculi) while boys with PAE exhibited higher FA (Callosal body, Cingulum, Corticospinal tract, Optic radiation, Superior longitudinal fasciculus) relative to age-matched controls. When gonadal hormone levels were examined in relation to DTI measures, additional group differences in FA were revealed, demonstrating that neuroendocrine factors are associated with PAE-related brain alterations.

CONCLUSIONS

These findings provide human evidence that PAE relates to sex-specific differences in WM microstructure, and underlying alterations in gonadal hormone function may, in part, contribute to these effects. Determining PAE-effects on neuroendocrine function among humans is an essential first step towards developing novel clinical (e.g., assessment or intervention) tools that target hormone systems to improve on-going brain development among children and adolescents with FASD.

Sex-specific effects of developmental alcohol exposure on cocaine-induced place preference in adulthood

Fetal Alcohol Syndrome (FAS) is associated with high rates of drug addiction in adulthood. One possible basis for increased drug use in this population is altered sensitivity to drug-associated contexts. This experiment utilized a rat model of FASD to examine behavioral and neural changes in the processing of drug cues in adulthood. Alcohol was given by intragastric intubation to pregnant rats throughout gestation and to rat pups during the early postnatal period (ET group). Controls consisted of a non-treated group (NC) and a pair-fed group given the intubation procedure without alcohol (IC). On postnatal day (PD) 90, rats from all treatment groups were given saline, 0.3mg/kg, 3.0mg/kg, or 10.0mg/kg cocaine pairings with a specific context in the conditioned place preference (CPP) paradigm. While control animals of both sexes showed cocaine CPP at the 3.0 and 10.0mg/kg doses, ET females also showed cocaine CPP at 0.3mg/kg. This was accompanied by a decrease in c-Fos/GAD₆₇ cells in the nucleus accumbens (NAc) shell and GAD₆₇-only cells in the NAc shell and PFC at this 0.3mg/kg dose. ET males failed to show cocaine CPP at the 3.0mg/kg dose. This was associated with an increase in c-Fos only-labeled cells in the NAc core and PFC at this 3.0mg/kg dose. These results suggest that developmental alcohol exposure has a sexually-dimorphic effect on cocaine's conditioning effects in adulthood and the NAc.

Acute alcohol exposure during neurulation: Behavioral and brain structural consequences in adolescent C57BL/6J mice

Prenatal alcohol exposure (PAE) can induce physical malformations and behavioral abnormalities that depend in part on thedevelopmental timing of alcohol exposure. The current studies employed a mouse FASD model to characterize the long-term behavioral and brain structural consequences of a binge-like alcohol exposure during neurulation; a first-trimester stage when women are typically unaware that they are pregnant. Time-mated C57BL/6J female mice were administered two alcohol doses (2.8g/kg, four hours apart) or vehicle starting at gestational day 8.0. Male and female adolescent offspring (postnatal day 28-45) were then examined for motor activity (open field and elevated plus maze), coordination (rotarod), spatial learning and memory (Morris water maze), sensory motor gating (acoustic startle and prepulse inhibition), sociability (three-chambered social test), and nociceptive responses (hot plate). Regional brain volumes and shapes were determined using magnetic resonance imaging. In males, PAE increased activity on the elevated plus maze and reduced social novelty preference, while in females PAE increased exploratory behavior in the open field and transiently impaired rotarod performance. In both males and females, PAE modestly impaired Morris water maze performance and decreased the latency to respond on the hot plate. There were no brain volume differences; however, significant shape differences were found in the cerebellum, hypothalamus, striatum, and corpus callosum. These results demonstrate that alcohol exposure during neurulation can have functional consequences into adolescence, even in the absence of significant brain regional volumetric changes. However, PAE-induced regional shape changes provide evidence for persistent brain alterations and suggest alternative clinical diagnostic markers.

Prenatal programming of neuroendocrine reproductive function

It is now well recognized that the gestational environment can have long-lasting effects not only on the life span and health span of an individual but also, through potential epigenetic changes, on future generations. This article reviews the "prenatal programming" of the neuroendocrine systems that regulate reproduction, with a specific focus on the lessons learned using ovine models. The review examines the critical roles played by steroids in normal reproductive development before considering the effects of prenatal exposure to exogenous steroid hormones including androgens and estrogens, the effects of maternal nutrition and stress during gestation, and the effects of exogenous chemicals such as alcohol and environment chemicals. In so doing, it becomes evident that, to maximize fitness, the regulation of reproduction has evolved to be responsive to many different internal and external cues and that the GnRH neurosecretory system expresses a degree of plasticity throughout life. During fetal life, however, the system is particularly sensitive to change and at this time, the GnRH neurosecretory system can be "shaped" both to achieve normal sexually differentiated function but also in ways that may adversely affect or even prevent "normal function". The exact mechanisms through which these programmed changes are brought about remain largely uncharacterized but are likely to differ depending on the factor, the timing of exposure to that factor, and the species. It would appear, however, that some afferent systems to the GnRH neurons such as kisspeptin, may be critical in this regard as it would appear to be sensitive to a wide variety of factors that can program reproductive function. Finally, it has been noted that the prenatal programming of neuroendocrine reproductive function can be associated with epigenetic changes, which would suggest that in addition to direct effects on the exposed offspring, prenatal programming could have transgenerational effects on reproductive potential.

Neuronal basis of reproductive dysfunctions associated with diet and alcohol: From the womb to adulthood

The theory that individuals are born as tabula rasa and that their knowledge comes from experience and perception is no longer true. Studies suggest that experience is gained as early as in the mother's womb. Moreover, environmental stressors like alcohol or inadequate diet can affect physiological systems such as the hypothalmic-pituitary-gonadal (HPG) axis. The effects of these stressors can manifest as alterations in sexual development and adult reproductive functions. In this review, we consider and compare evidence from animal models and human studies demonstrating the role of environmental stressors (alcohol and under- or overnutrition) on the HPG axis. We review the role of alcohol and inadequate diet in prenatal reproductive system programming and consider specific candidate neurons in the adult hypothalamus through which reproductive function is being regulated. Finally, we review evidence from animal studies on the role that alcohol and diet play in fertility and reproductive disorders. We conclude that in order to better understand reproductive failure in animals and humans we need to consider in utero development and pay more attention to early life experience when searching for the origins of reproductive diseases.

Effects of prenatal alcohol exposure on testosterone and pubertal development

BACKGROUND

Animal models have demonstrated fetal alcohol-related disruptions in neuroendocrine function in the hypothalamic-pituitary-gonadal axis and downstream effects on pubertal development and sexual behavior in males and females, but little is known about these effects in humans. This study examined whether prenatal alcohol exposure is associated with alterations in testosterone during adolescence and whether it affects timing of pubertal development.

METHODS

The sample consisted of 265 African American adolescents from the Detroit Longitudinal Cohort Study for whom testosterone and/or pubertal development data were available. Subjects were offspring of women recruited at their first prenatal clinic visit to over represent moderate-to-heavy alcohol use, including a 5% random sample of low-level drinkers/abstainers. Mothers were interviewed at every prenatal visit about their alcohol consumption using a timeline follow-back approach and about their smoking and drug use and sociodemographic factors. At age 14 years, adolescents provided salivary samples, which were analyzed for testosterone (pg/ml), self-reported Tanner stages for pubertal development, and age at menarche (females).

RESULTS

Prenatal alcohol exposure was related to elevated testosterone concentrations for males and females but not to changes in Tanner stages or age at menarche, after controlling for confounders. In regression models stratified by alcohol exposure, the expected relation between testosterone and pubic hair development was seen among males with light-to-no prenatal alcohol exposure, but not among those with moderate-to-heavy prenatal alcohol exposure. This interaction between testosterone and prenatal alcohol exposure was confirmed in multivariable models including an alcohol exposure group × testosterone interaction term and potential confounders.

CONCLUSIONS

This study is the first to show a relation between prenatal alcohol exposure and increased testosterone during adolescence and evidence of decreased testosterone responsiveness in tissues related to pubertal development in humans. Further studies examining androgen receptor expression and other hormonal and cellular factors affecting pubertal development may reveal important mechanisms underlying these teratogenic effects of alcohol exposure.

Low-dose thyroxine attenuates autism-associated adverse effects of fetal alcohol in male offspring's social behavior and hippocampal gene expression

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is characterized by neurodevelopmental anomalies manifesting in cognitive and behavioral deficits in the offspring with diverse severities. Social behavior is affected in FASD, and these deficits overlap with those of autism spectrum disorder (ASD). Identifying some of the molecular characteristics related to ASD in an animal model of FASD could ultimately provide details on the underlying molecular mechanisms of both disorders that could lead to novel treatments.

METHODS

Pregnant Sprague-Dawley rats received the following diets: control (C; ad libitum standard laboratory chow), nutritional control pair-fed (PF), ethanol (EtOH), or an EtOH diet supplemented with 0.3, 1.5, or 7.5 mg thyroxine (T4)/l in the diet. Social behavior and memory were tested in the adult offspring. Plasma total T4, free T3 (fT3), and thyroid-stimulating hormone (TSH) levels were measured. Hippocampal expression of Gabrb3, Ube3a, Nr2b, Rasgrf1, and Dio3 were measured by RT-qPCR and protein levels of Mecp2 and Slc25a12 by Western blotting.

RESULTS

Adult male offspring of EtOH dams showed elevated fT3 and low TSH levels. Adult male, but not female, offspring of EtOH dams exhibited social behavior and memory deficits. Expression of autism candidates, Gabrb3, Ube3a, Mecp2, and Slc25a12, was significantly increased in the hippocampus of male offspring of EtOH dams. Hippocampal Nr2b and Dio3 were also increased, while Rasgrf1 was decreased in the same population. Peripheral thyroid function, social behavioral deficits, and altered expression of the above genes were normalized by simultaneous administration of 0.3 mg/l T4 in the EtOH diet.

CONCLUSIONS

Our data suggest that social interaction deficits of FASD share molecular mechanism with ASD by showing altered hippocampal expression of several ASD candidate genes. Social interaction deficits as well as the gene expression changes in the offspring of EtOH-consuming dams can be reversed by low dose of thyroid hormone supplementation to the mothers.

Prenatal ethanol exposure delays the onset of spermatogenesis in the rat

BACKGROUND

During late prenatal and early postnatal life, the reproductive system in males undergoes an extensive series of physiological and morphological changes. Prenatal ethanol (EtOH) exposure has marked effects on the development of the reproductive system, with long-term effects on function in adulthood. The present study tested the hypothesis that prenatal EtOH exposure will delay the onset of spermatogenesis.

METHODS

Development of the seminiferous tubules and the onset of spermatogenesis were examined utilizing a rat model of fetal alcohol spectrum disorder (FASD). Male offspring from ad libitum-fed control (C), pair-fed (PF), and EtOH-fed (prenatal alcohol exposure [PAE]) dams were terminated on postnatal (PN) days 5, 15, 18, 20, 25, 35, 45, and 55, to investigate morphological changes through morphometric analysis of the testes from early neonatal life through young adulthood.

RESULTS

PAE males had lower relative (adjusted for body weight) testis weights compared with PF and/or C males from PN15 through puberty (PN45). In addition, fewer gonocytes (primordial germ cells) were located on the basal lamina on PN5, while more of those touching the basal lamina were dividing in PAE compared with PF and C males, suggesting delayed cell division and migration processes. As well, the percentage of tubules with open lumena was lower in PAE compared with PF and C males on PN18 and 20, and PAE males had fewer primary spermatocytes per tubule on PN18 and round spermatids per tubule on PN25 compared with C males. Finally, the percentage of tubules at stages VII and VIII, when mature spermatids move to the apex of the epithelium and are released, was lower in PAE compared with PF and/or C males in young adulthood (PN55).

CONCLUSIONS

Maternal EtOH consumption appears to delay both reproductive development and the onset of spermatogenesis in male offspring, with effects persisting at least until young adulthood.

Sexually dimorphic effects of alcohol exposure during development on the processing of social cues

AIMS

The study used an animal model of fetal alcohol spectrum disorders (FASD) to investigate the impact of alcohol exposure during a period equivalent to all three trimesters in humans on social recognition memory. It was hypothesized that the effects on specific aspects of social recognition memory would be sexually dimorphic.

METHODS

This study exposed rats to ethanol during both the prenatal and early postnatal periods. Two control groups included a group exposed to the administration procedures but not ethanol and a non-treated group. At approximately 90 days, all rats were tested repeatedly in a test of social recognition memory with a juvenile animal of the same sex. Experimental rats of both sexes were allowed to investigate an unknown juvenile for either 2, 3 or 5 min and then, after a delay of 30, 60, 120 and 180 min, were allowed to investigate the same juvenile for 5 min.

RESULTS

Male rats investigated the juvenile for much longer than female rats. Ethanol-exposed male rats showed a deficit in recognition memory that was evident with longer delays when the initial investigation time was either 2- or 3-min long. In contrast, ethanol-exposed female rats showed a deficit in recognition memory only when the initial investigation period was of 2 min. Measurement of oxytocin receptor binding in the amygdala region indicated that ethanol exposure lowered oxytocin receptor binding in females but not males.

CONCLUSIONS

The results suggest that ethanol exposure during development caused a deficit in memory duration but not encoding in males and a deficit in encoding but not memory duration in females. The deficit in ethanol-exposed females may be related to changes in oxytocin receptors in the amygdala.

Organizational influence of the postnatal testosterone surge on the circadian rhythm of core body temperature of adult male rats

The suprachiasmatic nucleus (SCN) of the hypothalamus coordinates physiological and behavioral circadian rhythms such as activity, body temperature, and hormone secretion. Circadian rhythms coordinated by the SCN often show sex differences arising from both organizational and activational effects of gonadal hormones. In males, little is known about the organizational role of testosterone on the circadian regulation of core body temperature (CBT) in adulthood. To explore this, we castrated or sham-operated male rats on the day of birth, and at 4 months of age, implanted them with transmitters that measured CBT rhythms under a 12:12 light/dark cycle. This study revealed a significantly earlier rise in CBT during the light phase in neonatally castrated males. Subsequently, we found that treating neonatally castrated males with testosterone propionate (TP) in adulthood did not reverse the effect of neonatal castration, thus indicating an organizational role for testosterone. In contrast, a single injection of TP at the time of neonatal surgery, to mimic the postnatal surge of testosterone, coupled with TP treatment in adulthood, normalized the circadian rise in CBT. In a final study we examined CBT circadian rhythms in intact adult male and female rats and detected no differences in the rise of CBT during the light phase, although there was a greater overall elevation in female CBT. Together, results of these studies reveal an early organizational role of testosterone in males on the timing of the circadian rise of CBT, a difference that does not appear to reflect "defeminization".

Prenatal alcohol exposure: foetal programming, the hypothalamic-pituitary-adrenal axis and sex differences in outcome

Prenatal exposure to alcohol has adverse effects on offspring neuroendocrine and behavioural functions. Alcohol readily crosses the placenta, thus directly affecting developing foetal endocrine organs. In addition, alcohol-induced changes in maternal endocrine function can disrupt the normal hormonal interactions between the pregnant female and foetal systems, altering the normal hormone balance and, indirectly, affecting the development of foetal metabolic, physiological and endocrine functions. The present review focuses on the adverse effects of prenatal alcohol exposure on offspring neuroendocrine function, with particular emphasis on the hypothalamic-pituitary-adrenal (HPA) axis, a key player in the stress response. The HPA axis is highly susceptible to programming during foetal and neonatal development. Here, we review data demonstrating that alcohol exposure in utero programmes the foetal HPA axis such that HPA tone is increased throughout life. Importantly, we show that, although alterations in HPA responsiveness and regulation are robust phenomena, occurring in both male and female offspring, sexually dimorphic effects of alcohol are frequently observed. We present updated findings on possible mechanisms underlying differential effects of alcohol on male and female offspring, with special emphasis on effects at different levels of the HPA axis, and on modulatory influences of the hypothalamic-pituitary-gonadal hormones and serotonin. Finally, possible mechanisms underlying foetal programming of the HPA axis, and the long-term implications of increased exposure to endogenous glucocorticoids for offspring vulnerability to illnesses or disorders later in life are discussed.

Prenatal ethanol exposure alters core body temperature and corticosterone rhythms in adult male rats

Ethanol's effects on the developing brain include alterations in morphology and biochemistry of the hypothalamus. To examine the potential functional consequences of ethanol's interference with hypothalamic differentiation, we studied the long-term effects of prenatal ethanol exposure on basal circadian rhythms of core body temperature (CBT) and heart rate (HR). We also examined the late afternoon surge in corticosterone (CORT). Core body temperature and HR rhythms were studied in separate groups of animals at 4, 8, and 20 months of age. The normal late afternoon rise in plasma CORT was examined in freely moving male rats at 6 months of age via an indwelling right atrial cannula. Results showed that the CBT circadian rhythm exhibited an earlier rise after the nadir of the rhythm in fetal alcohol-exposed (FAE) males at all ages compared to controls. At 8 months of age, the amplitude of the CBT circadian rhythm in FAE males was significantly reduced to the level observed in controls at 20 months. No significant effects of prenatal ethanol exposure were observed on basal HR rhythm at any age. The diurnal rise in CORT secretion was blunted and prolonged in 6-month-old FAE males compared to controls. Both control groups exhibited a robust surge in CORT secretion around the onset of the dark phase of the light cycle, which peaked at 7:30 p.m. Whereas FAE males exhibited a linear rise beginning in mid afternoon, which peaked at 9:30 p.m. These results indicate that exposure to ethanol during the period of hypothalamic development can alter the long-term regulation of circadian rhythms in specific physiological systems.

Prenatal ethanol exposure alters the effects of gonadectomy on hypothalamic-pituitary-adrenal activity in male rats

Prenatal ethanol exposure has marked effects on development of the hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes. In adulthood, ethanol-treated rats show altered gonadal hormone responses and reproductive function, and increased HPA responsiveness to stressors. Importantly, prenatal ethanol differentially alters stress responsiveness in adult males and females, raising the possibility that the gonadal hormones play a role in mediating prenatal ethanol effects on HPA function. To examine a possible testicular influence on HPA activity in males, we compared the effects of gonadectomy on HPA stress responses of adult male offspring from ethanol, pair-fed (PF) and ad libitum-fed control dams. Intact ethanol-treated rats showed increased adrenocorticotrophic hormone (ACTH) but blunted testosterone and luteinising hormone (LH) responses to restraint stress, and no stress-induced elevation in arginine vasopressin (AVP) mRNA levels compared to those observed in PF and/or control rats. Gonadectomy: (i) significantly increased ACTH responses to stress in control but not ethanol-treated and PF males; (ii) eliminated differences among groups in plasma ACTH and AVP mRNA levels; and (iii) altered LH and gonadotrophin-releasing hormone responses in ethanol-treated males. Taken together, these findings suggest that central regulation of both the HPA and HPG axes are altered by prenatal ethanol exposure, with normal testicular influences on HPA function markedly reduced in ethanol-treated animals. A decreased sensitivity to inhibitory effects of androgens could contribute to the HPA hyperresponsiveness typically observed in ethanol-treated males.

Determination of endogenous testosterone in rat tissues following fetal alcohol exposure using HPLC with UV detection

A novel method for quantitation of brain neurosteroid levels using HPLC with UV detection is described. In this simple and reliable method, testosterone from the brain and whole blood, and the internal standard, 17alpha-methyl testosterone, were extracted in 20% acetonitrile-phosphate buffer (pH 2.8), followed by solid phase extraction (SPE). The calibration curve was linear in concentration ranges from 0.1 to 10 ng from 0.2 g of tissue. We successfully applied this method to the analysis of endogenous testosterone in the male offspring of rats exposed to alcohol in utero. The concentration of testosterone at 21 post delivery in fetal alcohol exposure (FAE) group was significantly greater than the concentrations in either pair-fed or the ad libitum controls. These results support the usefulness of this method as a means of quantitating neurosteroids, and illustrate its applicability to fetal alcohol exposure.

Effects of prenatal alcohol exposure on forepaw digit length and digit ratios in rats

Prenatal exposure to alcohol can cause limb and digit defects. Variations in digit ratios in humans are associated with prenatal testosterone exposure. Since prenatal alcohol can reduce testosterone in rats, the effects of prenatal alcohol were measured on rat digit length. Pregnant Sprague-Dawley rats were intubated with 0 g/kg, 4 g/kg, or 6 g/kg of ethanol from Gestational Day 8 (GD8) to GD20. The 0-g/kg group and a nonintubated group served as controls. At postnatal day 31, forepaw digit lengths were measured and digit ratios calculated. Females had smaller digits on both forepaws and higher digit ratios on the right forepaw than males. Rats exposed to 6 g/kg of ethanol had smaller digits than controls on both forepaws and higher digit ratios than controls on the left forepaw. Rat digit ratios differ between the sexes, and prenatal alcohol exposure affects digit ratios. The results are consistent with a perinatal disruption of testosterone levels by alcohol and/or of testosterone's effects on digit length and ratios. An alternate interpretation is consistent with a retinoic acid-mediated effect of alcohol on digit length and ratios.

Fetal testosterone surge: specific modulations induced in male rats by maternal stress and/or alcohol consumption

Plasma testosterone (T) was measured in control male and female rats on gestational days 16, 17, 18, 19, and 20 and on days 17-20 in males from dams who were fed ethanol and/or were stressed during pregnancy. Circulating T in control males showed an earlier rise, yielding a longer period of prenatal T elevation, than was reported previously (Endocrinology 106 (1980)306). Compared to control males, exposure to alcohol-alone augmented T on days 18 and 19, stress-alone attenuated prenatal T, and the combination of stress and alcohol completely blocked the normal rise in T between days 17 and 18. When these prenatal alterations in T are viewed along with effects these same treatments have on the postparturient T surge (Horm. Behav. 41 (2002) 229), a possible explanatory mechanism emerges for the uniquely different behavioral patterns of sexual behavior differentiation induced in males by prenatal exposure to alcohol, stress, or both factors. Whereas the potential for feminine behavior is retained to the extent that either the prenatal or the neonatal T surge is attenuated, the male potential is more sensitive to reductions in the fetal surge and is maximally disrupted if both the prenatal and the postparturitional T surges are suppressed.

Impact of in utero exposure to EtOH on corpus callosum development and paw preference in rats: protective effects of silymarin

BACKGROUND

Using a rat model we have found that the bioflavonoid silymarin (SY) ameliorates some of the negative consequences of in utero exposure to ethanol (EtOH). In the current study our aim was to determine if laterality preference and corpus callosum development were altered in rat offspring whose mothers were provided with a concomitant administration of SY with EtOH throughout gestation.

METHODS

We provided pregnant Fisher/344 rats with liquid diets containing 35% ethanol derived calories (EDC) throughout the gestational period. A silymarin/phospholipid compound containing 29.8% silybin was co administered with EtOH to a separate experimental group. We tested the offspring for laterality preference at age 12 weeks. After testing the rats were sacrificed and their brains perfused for later corpus callosum extraction.

RESULTS

We observed incomplete development of the splenium in the EtOH-only offspring. Callosal development was complete in all other treatment groups. Rats from the EtOH-only group displayed a left paw preference; whereas control rats were evenly divided between right and left paw preference. Inexplicably both SY groups were largely right paw preferring.

CONCLUSIONS

The addition of SY to the EtOH liquid diet did confer some ameliorative effects upon the developing fetal rat brain.

Postparturitional testosterone surge in male offspring of rats stressed and/or fed ethanol during late pregnancy

Male offspring of rats exposed to restraint stress and/or alcohol during late pregnancy show aberrant patterns of sexual behavior masculinization and defeminization that vary as a function of treatment. The impact of these treatments on the postparturitional testosterone (T) surge that contributes to sexual behavior differentiation was investigated. Plasma T was measured using radioimmunoassay in individual males sampled on day 21 of gestation within 10 min of cesarean delivery or 1, 2, or 4 h thereafter. Neonatal T in the group exposed only to stress did not differ from that in the control group. T was lower than control levels at birth in both alcohol groups. The magnitude of the T surge that occurred during the first hour of birth in the control group was diminished by 50% in both alcohol groups, whose T pattern was very similar. There was no common alteration in postparturitional T associated with the increased lordotic behavior potential that males in all three treatment groups typically share, nor were there idiosyncratic endocrine abnormalities linked to the very different male copulatory pattern each exhibits. Exposure to an abnormal T milieu during fetal as well as neonatal ontogeny may underlie the etiology of the different sexual behavior patterns exhibited by males exposed to stress and/or alcohol. Possible unique effects each treatment exerts on perinatal plasma T and it's aromatization to estradiol in hypothalamic targets are discussed.

Gender differences in brain and behavior: hormonal and neural bases

This article briefly discusses the difficulties in determining the brain-behavior relationship and reviews the literature on some potential mechanisms underlying gender differences in behavioral responses. Mechanisms that are discussed include genetic effects, organizational effects of gonadal hormones, genomic actions of steroids, nongenomic effects of steroids, and environmental influences. The review is an introduction to the articles presented in this special volume on gender differences in brain and behavior.

Androgen threshold to activate copulation differs in male rats prenatally exposed to alcohol, stress, or both factors

Few male rats prenatally exposed to a combination of alcohol and stress copulate spontaneously. This study determined adult sensitivity to testosterone (T) in males prenatally exposed to alcohol, to stress, or to both factors. Sexually naive males were tested with receptive females following castration and implantation of 20-, 30-, or 45-mm Silastic T-filled capsules. Serum T levels provided by these implants were measured. The behavior shown by males exposed only to prenatal alcohol did not differ from untreated control animals at any T dosage. Prenatal stress alone diminished the copulatory potential below control levels only when the intermediate T dosage was provided. Few males exposed to both alcohol and stress copulated under the lowest or the intermediate dose of adult T replacement, but most ejaculated normally when the largest capsule was implanted. The threshold to the sexual behavior-activating-properties of adult T exposure was moderately raised by prenatal stress but was severely affected when prenatal stress was combined with alcohol. We conclude that a diminished sensitivity to androgen in adulthood underlies some copulatory deficits resulting from treatments that alter fetal T levels. Such deficits may be concealed when behavior is evaluated in gonadally intact animals.

Assessment of the U.S. Environmental Protection Agency methods for identification of hazards to developing organisms, Part I: The reproduction and fertility testing guidelines

BACKGROUND

Successful reproduction depends on the coordination of many processes, particularly the normal development and subsequent maturation of the sexual organs. The Food Quality Protection Act of 1996 mandates that the U.S. Environmental Protection Agency must protect infants and children from the effects of toxins, including those that affect the reproductive system. Therefore, the Agency finds itself at a critical juncture to make sure that the methods it requires for toxicity testing, the Health Effects Test Guidelines or Series 870 Guidelines, are adequate to determine possible toxicity to children.

METHODS AND RESULTS

We found that two testing protocols included in the core guidelines assess toxicological effects on developing animals. This article aims to provide a detailed analysis of the protocols included in the Reproduction and Fertility Effects Test Guideline. An accompanying article assesses the Developmental Toxicity Testing Guideline. We conducted this analysis on the basis of whether the test would yield the information needed to adequately determine risk to infants and children.

CONCLUSIONS

Our analysis concludes that given the limitations inherent in testing for reproduction and fertility effects during development, it is necessary to include a safety factor during risk assessment of chemicals. This action will fulfill the mandate expressed in the FQPA to protect infants and children from environmental hazards.

Fetal alcohol exposure blocks full masculinization of the dorsolateral nucleus in rat spinal cord

Male rats prenatally exposed to a combination of stress and ethanol show severely impaired ejaculatory patterns. This study examined two sexually dimorphic nuclei in the lumbar spinal cord implicated in the control of male copulatory reflexes in rats whose mothers were exposed to alcohol, to stress, or to both treatments during pregnancy. Alcohol exposure led to a marked decrease (22%) in the number of motor neurons in the dorsolateral nucleus (DLN) of the adult male offspring, but no significant change in cell count was detectable in the sexually dimorphic nucleus of the bulbocavernosus (SNB). The combination of alcohol and stress did not enhance the effect on the DLN above that produced by alcohol alone. Somal sizes in the DLN and SNB were not altered by any of the treatment conditions. Alcohol exposure probably leads to incomplete masculinization of the DLN in male rats by decreasing testicular steroidogenesis during the fetal stage(s) when sexual differentiation is ongoing in that CNS structure.

Alcohol's possible covert role: brain dysfunction, paraphilias, and sexually aggressive behaviors

A number of studies have suggested a relationship between sexually anomalous behavior and brain dysfunction. However, in most cases, the etiology of this dysfunction remains elusive. In this paper, alcohol exposure in utero (fetal alcohol syndrome) is offered as one possible explanation for the neurophysiological abnormalities that appear to characterize a notable proportion of individuals within the paraphilic and sexually aggressive populations. It is noteworthy that the teratogenic effects of alcohol upon humans and animals often leads to a number of the behavioral and physiological abnormalities exhibited by some of these individuals.

Maternal adrenalectomy eliminates a surge of plasma dehydroepiandrosterone in the mother and attenuates the prenatal testosterone surge in the male fetus

Previous work has established a number of sex-related deficits in immune function, behavior, and endocrine responses to stress in the offspring of dams exposed to ethanol. To examine the potential role of maternal glucocorticoids as a mediator of these sexually dimorphic effects in the fetus, we examined the influence of prenatal alcohol exposure in the presence or absence of maternal glucocorticoids on fetal plasma corticosterone (CORT) production. An additional question to be addressed by these studies was whether maternal adrenalectomy could eliminate the known inhibition by ethanol of the prenatal surge of plasma testosterone in male fetuses. Pregnant dams were adrenalectomized (ADX) or sham-adrenalectomized on gestational day (G) 7 and placed on a liquid diet containing 35% ethanol-derived calories or pair-fed an isocaloric control diet throughout the experiment. On G18, G19, and G21, plasma levels of CORT, testosterone, and dehydroepiandrosterone (DHEA) were measured in male and female fetuses and their mothers. Ethanol administration consistently increased maternal plasma CORT levels but did not significantly alter CORT levels in the fetus. Maternal ADX resulted in compensatory increases in fetal CORT levels that were lower in fetuses of ADX dams on alcohol, suggesting a direct effect of ethanol on fetal pituitary-adrenal activity. There were no significant sex differences in fetal plasma CORT levels in response to any of these manipulations. A novel surge of maternal plasma DHEA was found on G19 that was absent in plasma from ADX dams. In spite of the absence of a surge on G19, plasma DHEA levels of ADX dams rose from very low levels at G18 to levels on G21 that were significantly higher than in Sham dams. A normal testosterone surge was observed in male fetuses on G18 and G19 from sham-adrenalectomized dams administered the pair-fed diet. However, this surge was greatly attenuated in males administered ethanol and also in male fetuses from ADX dams. These results reveal a direct inhibitory influence of ethanol on fetal CORT secretion as well as on the prenatal testosterone surge in males. Furthermore, these studies demonstrate the presence of a surge of DHEA in the pregnant rat. Overall, these data suggest that there is a critical adrenal factor in the rat that regulates the maternal surge of DHEA on G19 and the prenatal testosterone surge of male fetuses on G18-19.

Gonadotropin secretion in infantile rats exposed to ethanol in utero

Previous studies have shown that fetal alcohol exposure (FAE) alters reproductive function in both male and female rats. In females, FAE delays the onset of puberty, reduces a preovulatory-like LH surge, and results in an early onset of acyclicity. In males exposed to ethanol in utero, the perinatal surge of testosterone is reduced. During the infantile period of the female rat, there is a dramatic increase in plasma follicle-stimulating hormone (FSH), which is thought to play a role in initiating ovarian activity and perhaps the onset of puberty. In this study, we determined the effects of FAE on the patterns of gonadotropin secretion during the infantile period [postnatal days (PND) 8-21] in both male and female rats. Timed pregnant dams were fed a liquid diet containing 35% ethanol-derived calories during the final week of gestation. Control dams were fed either an isocaloric diet with sucrose substituted for ethanol (pair fed, PF) or laboratory chow (chow fed, CF). Male and female pups were sacrificed on PND 8, 10, 12, 15, 18, and 21, and trunk blood was collected. In males, LH levels decreased to a nadir on PND 18, and this decrease was blunted by FAE (p < 0.05). In contrast, FSH secretion was not altered by FAE. In females, plasma FSH levels were greater than males, and increased to peak on PND 12. This FSH peak was significantly delayed in FAE females (p < 0.02). There was no age-related change in LH levels in FAE females, and LH levels were not altered by FAE. The delayed peak of FSH secretion by FAE correlates with the delay in puberty previously seen in females. To investigate this further, we examined the possibility that the delay in the peak of serum FSH in FAE females is due to a reduced number of FSH-producing gonadotrophs. FSH-containing gonadotrophs were identified by immunocytochemistry. Cell counts of FSH-immunoreactive cells in pituitaries from PND 8, 15, and 21 control-fed and FAE female rats showed developmental increases in the number of FSH gonadotrophs per unit area (p < 0.001), but no treatment differences were observed. Overall, these data show that fetal alcohol exposure can alter gonadotropin secretion in infantile life in male and female rats. Importantly, the delay in FSH secretion in females may ultimately play a role in the delay in puberty observed in the FAE female rat.

Absence of postnatal testosterone fails to demasculinize the male rat's corpus callosum

We had previously shown that elimination of testosterone from embryonic day 17 through adulthood reduced the midsagittal area of the male rat corpus callosum (CC). However, day 1 castration, performed after the 2-h post-birth testosterone surge, was without effect. To elucidate the contribution of this surge on the CC, male rats were delivered by cesarean section and castrated within 20 min. This procedure eliminated the 2-h postnatal rise in testosterone levels. The prenatal surge in testosterone, which occurs on embryonic day 18, remained intact. In adulthood, callosal area was examined in castrate males, sham males, and intact females. Castrate males and sham males had significantly larger CCs as compared to females. The two male groups did not differ from each other. Body weight was significantly higher in sham versus castrate males, establishing the effectiveness of the castration. These results show that hormonal organization of the CC in the male is the result of the independent action of prenatal testicular androgens, and suggest that the end of this period marks the end of callosal sensitivity to testicular hormone influence. In addition, this report documents sexual dimorphism of the CC in a third rat strain.

Loss of reproductive competence at an earlier age in female rats exposed prenatally to ethanol

Previous studies have shown that prenatal ethanol exposure can partially masculinize or defeminize neurobehavioral development of female rats. An early age of onset of anovulation is one of the primary characteristics of partial defeminization. Consequently, we examined the occurrence of anovulation in fetal alcohol-exposed (FAE) female rats at 2, 6, and 12 months of age using both vaginal cytology as well as wheel-running behavior. We assessed the ability of estrogen and progesterone to elicit proprioceptive behaviors and lordosis at 2 and 17 months of age. Female subjects were derived from Sprague-Dawley dams administered an ethanol liquid diet (35% ethanol-derived calories), a pair-fed isocaloric liquid diet, or fed lab chow from days 14 to 22 of gestation. Litter representatives were placed in a computer-monitored wheel-running apparatus under a 12-hr lighting schedule from 49 to 60 days of age. Vaginal smears were taken from littermates during this same period. This same procedure was conducted again from 180 to 196 and from 380 to 396 days of age, except that vaginal cytology was examined in the same animals immediately after wheel-running behavior was studied. At approximately 2 months of age, a normal cyclical pattern of wheel-running, characteristic of 4- to 5-day estrus cycles, was observed in all animals. No differences were detected in mean activity levels during the wheel-running period. This was accompanied by normal cyclic vaginal cytology and normal proprioceptive behaviors and lordosis. At 6 months of age, FAE females exhibited significantly reduced wheel-running.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of neonatal ethanol exposure on saccharin consumption

Prenatal ethanol exposure has been associated with alterations in a variety of sexually dimorphic behaviors in rats. This study examined the effects of neonatal ethanol exposure on saccharin consumption, a sexually dimorphic behavior in rats. Subjects were Sprague-Dawley rats that were artificially reared (AR) from postnatal day (PN) 4-PN12 through gastrostomy tubes with ethanol exposure limited to PN4-PN10. The AR groups included two ethanol doses (6 g/kg/day and 4 g/kg/day) and an isocaloric maltose-dextrin control. A sham surgery control group was also included. The AR subjects were returned to their dams on PN13. At 21 days of age, subjects were housed with one same-sex sibling and free access to rat chow and water until testing. Subjects were tested for saccharin preference and consumption at 110 days of age. Typically, male rats consume less saccharin than females, and this was evident in the 4 g/kg ethanol group and both control groups. However, this was not apparent among the 6 g/kg ethanol-exposed males. Furthermore, saccharin preference seemed to be reduced in the females exposed to 6 g/kg ethanol. These data suggest that the "sensitive period" for ethanol's effects on sex differences in saccharin consumption extends into postnatal life.

The effect of ultrasound exposure in utero on the development of the fetal mouse testis: adult consequences

The effects of exposure in utero to 1 MHz, continuous-wave ultrasound on adult growth and testicular development in the mouse was investigated. The spatial peak temporal average intensity (ISPTA) employed ranged from 1 to 10 W/cm2, with exposure durations (t) of 200 s to 20 s. Exposures were made on days 9, 12 or 15 of gestation. Results showed an increase in postpartum deaths, an increase in the number of stillbirths, and a decrease in litter size when I2 t > or = 1125 W2 s/cm4, such that there was significant loss of pups. Birthweights of pups from nearly all dosage groups was significantly lower than that of the sham or cage control groups. Results also showed that males exposed to ultrasound in utero had decreased testis size and decreased daily sperm production ranging from 9% to 30%. This study showed that ultrasound exposure in utero is capable of disrupting fetal development and having potential subsequent effects on fertility in the adult male.

Decreased postnatal testosterone and corticosterone concentrations in rats following acute intermittent prenatal hypoxia without alterations in adult male sex behavior

The prenatal and postnatal testosterone surges in the male rat are associated with neurobehavioral sexual differentiation of the brain. Both surges can be attenuated by maternal stress or other environmental factors that activate the maternal and/or fetal hypothalamic/pituitary/adrenal (HPA) axis during the last week of gestation. Since hypoxia is known to activate the HPA axis, we studied its effect during gestation on sexual differentiation in the male rat. We examined the influence of intermittent hypoxic exposure during gestation with respect to the postnatal testosterone surge and corticosterone levels, and subsequent development of adult reproductive and nonreproductive sexually dimorphic behaviors. Plasma testosterone and corticosterone concentrations of male neonates were measured after maternal exposure to acute, intermittent, prenatal hypoxia (9% O2 6 h/day from Day 15 to 21 of gestation). Relative to normoxic controls, acute, intermittent, prenatal hypoxia significantly attenuated the postnatal testosterone surge. Postpartum plasma corticosterone levels in these animals were also suppressed. In adulthood, prenatally hypoxic animals exhibited normal masculine sex behavior. Lordosis behavior in response to estrogen and progesterone priming was not significantly different between treatment groups. Saccharin preference, a nonreproductive, sexually dimorphic behavior, was not significantly influenced by prenatal hypoxic exposure. These results demonstrate that in the male acute intermittent prenatal hypoxia attenuates the postnatal testosterone surge. However, this reduction failed to result in significant alterations in the expression of sex related behaviors in adulthood.

Prenatal ethanol exposure: effects on androgen and nonandrogen dependent behaviors and on gonadal development in male rats

Prenatal exposure to alcohol may impair gonadal and behavioral development in male rats, possibly via reduction of perinatal androgenization. We examined locomotor activity on postnatal day 18 (PND 18), which is not influenced by perinatal androgens and juvenile play and testicular development (testes weight), which are dependent on perinatal androgen exposure, in rats whose dams consumed ethanol during pregnancy. Male offspring of pair-fed and lab chow-fed dams served as controls. Despite reduced anogenital distance at birth, indicating compromised perinatal androgenization, fetal ethanol-exposed males did not exhibit demasculinization of play behavior. Hyperactivity in fetal ethanol-exposed males indicated that the treatment regimen was sufficient to produce behavioral deficits. Testes weight was reduced in both ethanol-exposed and pair-fed offspring, indicating that nutritional deficits associated with maternal ethanol intake may impair normal gonadal development in male rats. The findings suggest that fetal ethanol exposure may influence gonadal development but not necessarily affect a gonadal hormone-dependent behavior.

Decreased postnatal testosterone surge in male rats exposed to ethanol during the last week of gestation

Prenatal alcohol exposure in the rat is known to interfere with the neurobehavioral sexual differentiation of the male brain. Because normal sexual differentiation of the male brain requires adequate levels of perinatal testosterone, we examined the effect of prenatal ethanol exposure on (1) the postnatal surge of testosterone and (2) the in vitro secretion of testosterone in response to luteinizing hormone (LH) stimulation of testes from fetal alcohol exposed (FAE) animals and controls. Sprague-Dawley dams were administered a fortified liquid diet containing 35% ethanol-derived calories, a pair-fed (PF) isocaloric liquid diet, or given ad libitum access to dry lab chow (CF). Dams were administered the liquid diets from days 7 or 14 through parturition. The postnatal surge of testosterone in FAE males was studied only in animals exposed to ethanol from day 14 through parturition. In the first experiment, FAE and PF males and females were delivered by cesarean section on day 22 of gestation (E22) and trunk blood collected at 0, 60, 120, and 240 min after parturition. Experiment 2 measured plasma testosterone in male pups that were killed at 0, 60, 120, 240, 360, and 480 min after delivery. Results showed that the postnatal testosterone surge of FAE males in both experiments was significantly attenuated compared with PF controls. No effect of prenatal ethanol was observed in female offspring. Female testosterone levels were several fold lower than male littermates, and no evidence of a postnatal testosterone surge was observed. Production of testosterone from testes was studied using an automated perifusion system.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered adult sexual behavior in the male rat following chronic prenatal hypoxia

The last week of gestation is a critical period for the sexual differentiation of the brain in the rat. Exposure to prenatal stress during this period has been shown to demasculinize and/or feminize adult male sexual behavior. Many of the neurochemical and endocrine responses to hypoxia are similar to that observed under stressful conditions such as restraint stress. Therefore, we examined the postnatal consequences on reproductive and nonreproductive sexually dimorphic behaviors in male offspring of dams exposed to chronic hypoxia during the last week of gestation. In addition, we examined sensorimotor development in offspring of both sexes. Pregnant Sprague-Dawley dams were exposed to continuous hypoxia (10.5% O2 from gestational day 15 to 21). Offspring were weaned at 22 days of age and group housed. Behavioral tests were conducted with littermate representatives. In adulthood, male rats prenatally exposed to hypoxia had significantly delayed initiation latencies of masculine sexual behavior and decreased number of ejaculations, but did not display a significant increase in feminine sex behavior potentials. Developmentally, animals exposed to prenatal hypoxia did not differ significantly from controls with respect to day of eye or ear opening, or the in times of righting reflex, negative geotaxis or cliff avoidance. Wire hanging latencies in hypoxic exposed animals were significantly greater than controls around the time of eye opening, but did not differ at earlier or later ages. A significant effect of hypoxia was detected on stride length at 95 days of age, but other aspects of gait patterns were similar to controls. No group differences in gait patterns were observed at 17 or 45 days of age. In addition, no significant differences were observed in open field activity, circadian locomotor activity, saccharin preference, or Morris water maze test. This hypoxia regimen did not influence the occurrence of the prenatal or postnatal surge of plasma testosterone. Overall, these results provide some evidence that, in males, mild, chronic prenatal hypoxia may result in incomplete masculinization of adult reproductive behavior in the absence of overt changes in perinatal testosterone surges.

Prenatal ethanol exposure alters ethanol-induced dopamine release in nucleus accumbens and striatum in male and female rats

Using in vivo microdialysis, ethanol-induced dopamine release in nucleus accumbens and striatum was examined in adult male and female Long-Evans rats exposed prenatally to ethanol and in controls. Following dialysis, ethanol intake was measured in an operant paradigm. Control rats showed increased dopamine release in nucleus accumbens and striatum in response to 0.5 g/kg ethanol, but not to 1.0 g/kg. Fetal ethanol-exposed rats showed no dopamine response at 0.5 g/kg. At 1.0 g/kg, fetal ethanol-exposed males showed increased dopamine release in both structures. Prenatally exposed females showed no change in accumbens, and decreased release in striatum. Fetal ethanol exposure did not significantly influence ethanol intake. The findings suggest that prenatal ethanol exposure influences subsequent neurochemical responses to ethanol; however, how these neurochemical measures are related to ethanol intake could not be determined in the present study. Data are discussed in terms of sex-specific shifts in the dose-response function for ethanol-induced dopamine release resulting from prenatal ethanol exposure.

Effects of postnatal exposure to alcohol on reproductive physiology and sexually dimorphic behavior in a marsupial, the gray short-tailed opossum (Monodelphis domestica)

The effects of postnatal exposure to alcohol on reproductive physiology and sexually dimorphic behavior and anatomy in adult male and female gray short-tailed opossums were examined. Female responsiveness to male pheromones and fertility in both sexes were essentially normal in postnatally alcohol-treated animals. However, aspects of sexually dimorphic behavior were masculinized and defeminized in females and demasculinized in males following gonadectomy in adulthood and treatment with male (testosterone) or female (estradiol) hormones. The possible role of alterations in neural aromatase activity by perinatal alcohol exposure in mediating these behavioral effects and the potential use of this marsupial species in perinatal alcohol studies are discussed.

Psychoanalysis, psychobiology, and homosexuality

The potential role of biological influences in human sexual orientation was considered more seriously during the early phases of psychoanalysis than in the years since World War II. Recently studies of homosexuality and heterosexuality in the neurosciences have attracted widespread attention both in the scientific and lay communities. The salience of these new data for psychoanalytic theory and practice is just beginning to be explored. In this article, we review research on sexual orientation in the following areas: genetics, crosscultural studies, studies of development in individuals with abnormal prenatal hormone exposure, childhood play patterns, and brain studies in both nonhumans and humans. Differences between male and female homosexuality are explored. We propose that psychoanalytic theory can grow and profit from a careful consideration of new findings in the psychobiology of sexuality, and that the interaction between mind and body is the appropriate purview of psychoanalysis.

Comparison of two weeks versus one week of prenatal ethanol exposure in the rat on gonadal organ weights, sperm count, and onset of puberty

Sprague-Dawley dams from Harlan Ind. (Indianapolis, IN) were administered a fortified ethanol liquid diet containing 35% ethanol derived calories for two weeks (E-2) beginning on day 7 or one week (E-1) beginning on day 13 of gestation and continuing through parturition. Control dams were pair-fed an isocaloric liquid diet containing no ethanol during these periods or remained on lab chow and water. E-2 dams consumed an average of 13.52 g ethanol/kg bwt during the first week of exposure (days 8-14) and 12.50 g ethanol/kg bwt the second week (days 14-20). E-1 dams consumed significantly less than E-2 dams during the second week (9.75 g/kg; p < 0.0001). Although the lower consumption in E-1 dams led to a significant decrease in maternal weight gained during the few days of pregnancy compared to E-2 dams, birthweights of E-1 offspring were significantly heavier than those of E-2 offspring (p < 0.05). No effect of ethanol was detected on anogenital distance at birth in either sex. Puberty was delayed in female offspring of both E-1 and E-2 dams (p < 0.01) as measured by age of vaginal opening. These data suggest that the primary teratogenic actions of ethanol in the rat on fetal growth, as well as delayed puberty in females, occur in the last week of gestation. In adult E-2 males, testis weight was significantly heavier than all other groups when indexed to body weight. No effect of prenatal ethanol exposure was observed on the indexed weights of prostate, epididymis, or seminal vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed onset of puberty and subtle alterations in GnRH neuronal morphology in female rats exposed prenatally to ethanol

Fetal alcohol exposed (FAE) animals exhibit physiological and behavioral deficits associated with reproduction including alterations in LH secretion and decreased sex behavior. Such deficits led us to examine the morphological characteristics and number of GnRH neurons in female rats prenatally exposed to ethanol. Sprague-Dawley dams (Harlan, Indianapolis, IN) were administered a fortified liquid diet (Sustacal) containing 35% ethanol derived calories from day 7 through parturition. Controls were pair-fed a similar isocaloric diet containing no ethanol during this period or allowed access to dry food pellets ad lib. Compared to both control groups, puberty was found to be significantly delayed in females that were exposed prenatally to ethanol. The median age of vaginal opening for chow-fed and pair-fed controls was 34-35 days compared to 38-39 days for FAE animals. A subgroup of these females was selected at 44 days of age on the basis of delayed onset of puberty and compared with pair-fed controls for the number and morphology of GnRH-immunoreactive staining (ir) neurons in the medial preoptic area (MPOA) and the diagonal band of Broca (DBB), regions which contain the majority of GnRH-IR cells in the rat brain. In both areas, light microscopic study revealed no differences in GnRH-IR cell number, nor were differences detected among the groups in the number of bipolar versus unipolar cells. However, a significant increase was observed in FAE brains compared to controls in the ratio of GnRH-IR neurons with irregular processes compared to smooth cell contours.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of prenatal ethanol exposure on scentmarking in the C57BL/6J and C3H/He mouse strains

In utero exposure to ethanol has been shown to alter sexually dimorphic behaviors in rats. However, it is not clear whether this phenomenon is robust in other species, such as the mouse, which is sensitive to ethanol-induced birth defects. Further, it is not known whether significant differences exist across murine strains. If similar to the classic teratogenic effects of ethanol, it would be expected that strain differences in sensitivity should be evident, with some strains demonstrating an alteration in sexually dimorphic behavior and other strains demonstrating little or no effect. As a first attempt to address these issues, we have examined two mouse strains widely used in prenatal alcohol research, the inbred C3H/He and C57BL/6J strains. Scentmarking was selected as the behavior of interest. It is robustly sexually dimorphic in the rat and mouse, with males marking more than females and preliminary reports have demonstrated that in utero ethanol exposure reduces this behavior in the male rat. In the mouse strains selected for study, pregnant females were provided with either a liquid diet consisting of 25% ethanol-derived calories or pair-fed an isocaloric liquid diet from gestation days 6-18. An additional control group was included which was fed laboratory chow ad lib throughout gestation. Male and female offspring of each strain were tested for scentmarking at 65-75 days of age. As expected, results showed that the effect of prenatal ethanol exposure on scentmarking varied with both strain and sex. In the C3H/He strain, scentmarking was reduced significantly in male ethanol-exposed offspring (i.e., the males were feminized).(ABSTRACT TRUNCATED AT 250 WORDS)