Endocrine disrupting chemicals and ovulation: Is there a relationship?

Although the potential for endocrine disrupting chemicals (EDCs) to disrupt female fecundity is great, few studies have assessed the threat to human reproduction. This study investigates levels of organochlorines in relation to their impact on women's menstrual cycles and ovulatory status. To address concerns of the Akwesasne Mohawk community in upstate New York regarding well-established exposure to EDCs, women's fertility and reproductive health endpoints, we recruited 215 women between the ages of 21 and 38 years to measure menstrual cycle characteristics and levels of local pollutants. Of these, 155 women collected saliva over the course of their menstrual cycle allowing for analysis of estradiol and progesterone levels and the determination of ovulatory status in relationship to their serum pollutant levels. A subset of participants (15) who did not commence cycling within a month of their enrollment were not included in the analysis, hence reducing the sample size to 140 participants. Additionally, a lipid panel, estradiol and progesterone were assessed in serum on Day 3 of the menstrual cycle. Median cycle length for women in the sample was 29 days. After aligning the cycles, 110 women were considered ovulatory and 45 (29%) anovulatory. Concentrations of groups of more persistent PCBs congeners, HCB, and p,p'-DDE did not differ significantly with ovulatory status. However, a sub-group of low-chlorinated PCB congeners, considered to be estrogenic were significantly higher among anovulatory women. These findings suggest that certain EDC's, ubiquitous in our environment, may adversely affect menstrual cycles and thus have the capacity to impair reproductive function, including likelihood of conception.

Neurochemical and behavioral effects of chronic unpredictable stress.

Chronic stress can influence behaviors associated with medial prefrontal cortex (mPFC) function, such as cognition and emotion regulation. Dopamine in the mPFC is responsive to stress and modulates its behavioral effects. The current study tested whether exposure to 10 days of chronic unpredictable stress (CUS) altered the effects of acute elevation stress on dopamine release in the mPFC and on spatial recognition memory. Male rats previously exposed to CUS or nonstressed controls were tested behaviorally, underwent microdialysis to assess mPFC dopamine levels or underwent blood sampling for corticosterone analysis. Dopamine in the mPFC significantly increased in both groups during acute elevation stress compared with baseline levels, but the level was attenuated in CUS rats compared with controls. Control rats exposed to elevation stress immediately before the T-maze test showed impaired performance, whereas CUS rats did not. No group differences were observed in general motor activity or plasma corticosterone levels following elevation stress. The present results indicate that prior exposure to this CUS procedure reduced dopamine release in the mPFC during acute elevation stress and prevented the impairment of performance on a spatial recognition test following an acute stressor. These findings may contribute to an understanding of the complex behavioral consequences of stress.

Urine cortisol concentration as a biomarker of stress is unrelated to IVF outcomes in women and men.

PURPOSE: Our primary objective was to assess associations between urine cortisol as a biomarker of psychological stress and in vitro fertilization (IVF) outcomes. A secondary objective was to assess associations between toxic metals and cortisol. METHODS: Urine and blood specimens were collected from 52 women and 28 male partners completing a first IVF procedure, on the day of oocyte retrieval. Urine cortisol was measured with an enzyme-linked immunosorbent assay. Mercury (Hg), cadmium (Cd), and lead (Pb) were determined in blood and Cd in urine by inductively coupled plasma-mass spectrometry. RESULTS: No associations were indicated for cortisol with IVF outcomes in multivariable regression models adjusted for covariates. However, we detected positive linear associations for cortisol and urine Cd (ß = 9.96, 95%CI 1.52, 21.44) and blood Hg (ß = 1.44, 95%CI 0.31, 3.18). An exploratory stratified analysis suggested a potential inverse association between urine cortisol and oocyte fertilization among women with low, but not high blood Hg. CONCLUSION: While limited, these preliminary data suggest that psychological stress may not play a major role in IVF outcomes, which therefore could be one less concern for couples and their clinicians. Our data also raise the possibility for toxic metals to modify associations between cortisol and IVF outcomes among women. However, these preliminary results require corroboration in an experimental animal model and confirmation in a larger, more definitive observational study.

Membrane progestin receptors in the midbrain ventral tegmental area are required for progesterone-facilitated lordosis of rats.

Progesterone (P4) and its metabolites, rapidly facilitate lordosis of rats partly through actions in the ventral tegmental area (VTA). The study of membrane progestin receptors (mPRs), of the Progestin and AdipoQ Receptor (PAQR) superfamily, has been limited to expression and regulation, instead of function. We hypothesized that if mPRs are required for progestin-facilitated lordosis in the VTA, then mPRs will be expressed in this region and knockdown will attenuate lordosis. First, expression of mPR was examined by reverse-transcriptase polymerase chain reaction (RT-PCR) in brain and peripheral tissues of proestrous Long-Evans rats. Expression of mPRα (paqr7) was observed in peripheral tissues and brain areas, including hypothalamus and midbrain. Expression of mPRß (paqr8) was observed in brain tissues and was abundant in the midbrain and hypothalamus. Second, ovariectomized rats were estrogen (E2; 0.09 mg/kg, SC), and P4 (4 mg/kg, SC) or vehicle-primed, and infused with antisense oligodeoxynucleotides (AS-ODNs) targeted against mPRα and/or mPRß intracerebroventricularly or to the VTA. Rats were assessed for motor (open field), anxiety (elevated plus maze), social (social interaction), and sexual (lordosis) behavior. P4-facilitated lordosis was significantly reduced with administration of AS-ODNs for mPRα, mPRß, or co-administration of mPRα and mPRß to the lateral ventricle, compared to vehicle. P4-facilitated lordosis was reduced, compared to vehicle, by administration of mPRß AS-ODNs, or co-administration of mPRα and mPRß AS-ODNs, but not mPRα AS-ODNs alone, to the VTA. No differences were observed for motor, anxiety, or social behaviors. Thus, mPRs in the VTA are targets of progestin-facilitated lordosis of rats.

Motivated behaviors and levels of 3α,5α-THP in the midbrain are attenuated by knocking down expression of pregnane xenobiotic receptor in the midbrain ventral tegmental area of proestrous rats.

INTRODUCTION: Progesterone (P4 ) and its product, 5α-pregnan-3α-ol-20-one (3α,5α-THP), act in the midbrain ventral tegmental area (VTA) to alter motivated behaviors, such as mating, and motor and anxiety behavior. Of interest is whether 3α,5α-THP formation requires the pregnane xenobiotic receptor (PXR), which is expressed in the midbrain of rats. AIM: The role of PXR in the midbrain for 3α,5α-THP formation, which precedes modulation of motivated behaviors, was investigated. METHODS: Rats had estrous cycle phase determined and were assessed when they were in diestrus or proestrus. Diestrous and proestrous rats were infused with control or antisense oligodeoxyribonucleotides (AS-ODNs) targeted against PXR to the VTA. MAIN OUTCOME MEASURES: In pilot studies, PXR gene and protein expression in the midbrain were determined with quantitative reverse transcriptase polymerase chain reaction and Western blotting, respectively. Diestrous and proestrous rats infused with control or AS-ODNs to the VTA were tested for anxiety (open field and plus maze), social (social interaction), and sexual (paced mating) behavior. Expression of PXR in the midbrain was verified with Western blotting. Plasma estradiol, P4 , dihydroprogesterone (DHP), and 3α,5α-THP levels, and brain P4 , DHP, and 3α,5α-THP levels were measured. We predicted that proestrous rats infused with PXR AS-ODNs would have decreased anti-anxiety, social, and sexual behavior, lower midbrain expression of PXR, and lower midbrain levels of 3α,5α-THP compared with controls. RESULTS: Results supported the hypothesis that formation of 3α,5α-THP requires PXR and may be important for motivated behaviors. PXR AS-ODN, compared with control, infusions to the VTA reduced PXR expression and 3α,5α-THP levels in the midbrain and attenuated sexual receptivity of proestrous rats. CONCLUSIONS: Knockdown of PXR in the midbrain reduces 3α,5α-THP levels and sexual receptivity of proestrous rats. Thus, PXR in the midbrain may be required for the observed increase in 3α-5α-THP during proestrus, which has subsequent effects on motivated, reproductive behaviors.

It is all About the Chase: Neurosteroidogenesis in Male Rats is Driven by Control of Mating Pace.

BACKGROUND: Masculine sexual behaviors are dependent on androstane-derived steroids; however, the modulatory effects of mating, and of mating control, on androstane neurosteroidogenesis remain largely unknown. OBJECTIVE: Herein, we investigated the effects of mating control, prior sexual experience, and age on brain region specific neurosteroidogenic responses in male rats. METHODS: Effects of acute sexual experience were tested in naïve male rats that either remained sexually- naïve, were exposed to a standard mating chamber, or were either given control of the mating pace in a standard mating chamber (male control) or mated wherein the female stimulus rat controlled the mating pace in a paced-mating chamber (female control). Aged (10-12 months) sexually responsive male rats were similarly euthanized from the homecage or engaged in male controlled or female controlled mating. All rats were euthanized immediately following exposure conditions for radioimmunoassay of steroids in midbrain, hypothalamus, hippocampus and cortex. RESULTS: Consummatory sexual behavior in male vs. female-controlled mating paradigms was altered by age and prior sexual experience. Male-controlled mating increased androstane neurosteroid metabolism, such that complementary increases in the testosterone (T) metabolite 5α-androstane-3α-17ß- diol (3α-diol) in the midbrain and hypothalamus of male rats corresponded to decreases in the prohormone, T. 3α-diol were increased in the hippocampus in response to the context alone, and to a lesser degree in response to mating. Mating diminished neurosteroidogenesis in the cortex. Neurosteroidogenesis was overall reduced in aged male rats compared to naïve controls, however, these effects were more prominent in sexually non-responsive aged male rats. CONCLUSION: Extending previous findings, these results indicate differential production of androstane neurosteroids in a mating exposure, age and brain region dependent manner.

Juvenile offspring of rats exposed to restraint stress in late gestation have impaired cognitive performance and dysregulated progestogen formation.

Gestational stress may have lasting effects on the physical and neurocognitive development of offspring. The mechanisms that may underlie these effects are of interest. Progesterone and its 5α-reduced metabolites, dihydroprogesterone and 5α-pregnan-3α-ol-20-one (3α,5α-THP), maintain pregnancy, have neurotrophic effects, and can enhance cognitive performance. We hypothesized that some of the deleterious effects of gestational stress on the cognitive performance of offspring may be related to progestogen formation. Pregnant rat dams were exposed to restraint under a bright light (thrice daily for 45 min) on gestational days 17-21 or were minimally handled controls. Dams that were exposed to restraint had lower circulating levels of 3α,5α-THP and significantly greater concentrations of corticosterone at the time of birth than did control dams. Male and female offspring, that were gestationally stressed or not, were cross-fostered to non-manipulated dams. Between postnatal days 28-30, offspring were assessed for object recognition, a prefrontal cortex (PFC)-dependent cognitive task. Restraint-exposed offspring performed more poorly in the object recognition task than did control offspring, irrespective of sex. As well, progesterone turnover to its 5α-reduced metabolites in the medial PFC (but not the diencephalon) was significantly reduced among restraint-exposed, compared to control, offspring. Progesterone turnover, and levels of 3α,5α-THP, positively correlated with performance in the object recognition task. Thus, restraint stress in late pregnancy impaired cognitive development and dysregulated progestogen formation in brain.

Neurosteroids for a successful pregnancy.

Steroid hormones play a critical role in the initiation and maintenance of pregnancy. In particular, the important role that the progesterone metabolite, and neurosteroid, allopregnanolone, may play in fetal and adolescent development is becoming increasingly evident. Unlike steroid hormones, neurosteroids act at nontraditional targets in the central and peripheral nervous systems, including GABA(A) receptor complexes. This commentary discusses the three works in this issue that elucidate the important role of allopregnanolone in the mechanisms that regulate stress hypo-sensitivity of rodents in late pregnancy, neuroprotective effects in fetal sheep exposed to a hypoxic insult, and the continuing role that prefrontal cortex formation of allopregnanolone may play on the cognitive development of gestationally stressed rat offspring, grown to adolescence. The narrative that these works comprise was facilitated by the 5(th) International Meeting on Steroids and the Nervous System (Torino, Italy), which is organized to update our knowledge on the relationships between steroid hormones synthesized in different organs and the nervous system. Topics covered in this most recent meeting included sex differences in, and hormonal influences on, cannabinoid-regulated biology; steroids and pain; the importance of co-regulatory factors for steroid receptor action in the brain; mechanism and role of estrogen-induced nonclassical signaling in the brain; vitamin D as the forgotten neurosteroid; neurosteroids and GABA(A) receptors; and pathogenic mechanisms mediated by glucocorticoid receptors in psychiatric disorders. The 6(th) International Meeting on Steroids and the Nervous System will be held in Torino, Italy in February 2011.

Immune stress in late pregnant rats decreases length of gestation and fecundity, and alters later cognitive and affective behaviour of surviving pre-adolescent offspring.

Immune challenge during pregnancy is associated with preterm birth and poor perinatal development. The mechanisms of these effects are not known. 5α-Pregnan-3α-ol-20-one (3α,5α-THP), the neuroactive metabolite of progesterone, is critical for neurodevelopment and stress responses, and can influence cognition and affective behaviours. To develop an immune challenge model of preterm birth, pregnant Long-Evans rat dams were administered lipopolysaccharide [LPS; 30 µg/kg/ml, intraperitoneal (IP)], interleukin-1ß (IL-1ß; 1 µg/rat, IP) or vehicle (0.9% saline, IP) daily on gestational days 17-21. Compared to control treatment, prenatal LPS or IL-1ß reduced gestational length and the number of viable pups born. At 28-30 days of age, male and female offspring of mothers exposed to prenatal IL-1ß had reduced cognitive performance in the object recognition task compared to controls. In females, but not males, prenatal IL-1ß reduced anxiety-like behaviour, indicated by entries to the centre of an open field. In the hippocampus, progesterone turnover to its 5α-reduced metabolites was lower in prenatally exposed IL-1ß female, but not in male offspring. IL-1ß-exposed males and females had reduced oestradiol content in hippocampus, medial prefrontal cortex and diencephalon compared to controls. Thus, immune stress during late pregnancy reduced gestational length and negatively impacted birth outcomes, hippocampal function and central neurosteroid formation in the offspring.

Pregnant women with more seizures have lower allopregnanolone concentrations.

Neuroactive steroids have rapid, nongenomic effects on neuronal excitability. The effects in humans are less clear. We compared seizure control and concentrations of neuroactive steroids, known to influence neuroexcitability in animal studies, in pregnant women. Participants were prospectively followed throughout pregnancy with seizure-medication diaries and blood samples, assayed for steroid concentrations with gas chromatography-mass spectrometry. Baseline seizure frequency was calculated for the preconception year, and it was determined if seizure frequency was increased in each trimester. The Wilcoxon rank-sum test was used to compare neuroactive steroid concentrations in between the group with increased frequency to the group without, as calculated for the respective trimester, with the Holm-Bonferroni method to correct for multiple comparisons. Among eighty-three pregnancies included, twenty-eight had increased seizure frequency during at least one trimester (15, 18 and 10, respectively) compared to preconception seizure frequency. Allopregnanolone concentrations were lower in the 3rd trimester (p < 0.001), with a similar trend in the 1st (p = 0.08), for pregnancies with increased compared to those with stable seizure frequency. Other neuroactive steroid concentrations were similar. Our findings suggest that lower allopregnanolone concentrations are associated with increased seizure frequency during pregnancy. Validation of these finding in a larger cohort has potential important clinical applications.

Effects and mechanisms of progestogens and androgens in ictal activity.

Steroid hormones, such as progestogens and androgens, influence seizures. Progestogens and androgens exert organizational and/or activational effects that may mitigate vulnerability to, and/or expression of, some seizure disorders. Progestogens, such as progesterone (P(4)) and its 5alpha-reduced metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), which vary across the reproductive cycle and lifespan, may protect against seizures through actions at intracellular progestin receptors (PRs) and membrane receptors, such as gamma-aminobutyric acid (GABA)(A) receptors. Similarly, androgens, such as testosterone (T), which also vary across the reproductive cycle and the lifespan, can have antiseizure effects. Some of these effects of T may be due to aromatization to estrogen and/or 5alpha-reduction to dihydrotestosterone (DHT), and its subsequent conversion through 3alpha-hydroxysteroid dehydrogenase to 5alpha-androstane-3alpha,17alpha-diol (3alpha-diol). Sensitivity to steroids in some individuals may be mitigated by differences in stress, developmental phase, reproductive status, endocrine status, and treatments, such as antiepileptic drugs (AEDs), which alter levels of these ligands and/or function of their target sites. The evidence implicating sex steroids in differences associated with hormonal, reproductive, developmental, stress, seizure type, and/or therapeutics are discussed.

Low doses of cocaine decrease, and high doses increase, anxiety-like behavior and brain progestogen levels among intact rats.

There are sex and hormonal differences in response to cocaine that have been demonstrated in people and animal models. Cocaine can alter secretion of progestogens, such as progesterone (P), and its neuroactive metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP). However, little research has been done on the neuroendocrine effects in the initiation phase of cocaine use. We hypothesize that some sex/hormonal differences in initiation phase responses to cocaine may be related to formation of progestogens. To investigate the role of progestogens in sex differences in response to acute cocaine, male and female rats in the high (proestrous) or low (diestrous) progestogen phase of the estrous cycle were administered cocaine (0, 5, 10, or 20mg/kg, IP). We examined cocaine's acute neuroendocrine effects on P and 3alpha,5alpha-THP levels, as well as its effects on acute psychomotor stimulation, anxiety, and sexual behaviors. Among rats that had P and/or 3alpha,5alpha-THP levels increased in response to cocaine, enhanced acute psychomotor stimulation was observed. Results suggest that cocaine produces U-shaped curves for progestogens, and anxiety-like behaviors. Male rats were less susceptible to these effects of cocaine than were proestrous or diestrous female rats. However, cocaine's disruption of sexual behaviors was similar among males and proestrous females. These data suggest a complex interaction between hormonal milieu and the neuroendocrine and behavioral effects of cocaine.

Sex differences in salivary cortisol in response to acute stressors among healthy participants, in recreational or pathological gamblers, and in those with posttraumatic stress disorder.

Sex differences in incidence and severity of some stress-related, neuropsychiatric disorders are often reported to favor men, suggesting that women may be more vulnerable to aberrant hypothalamic-pituitary-adrenal (HPA) axis responses to stress. In this review, we discuss several investigations that we, and others, have conducted assessing salivary cortisol as a measure of HPA function. We have examined basal cortisol among healthy men and women and also following acute exposure to stressors. Among healthy participants, men had higher basal cortisol levels than did women. In response to acute stressors, such as carbon dioxide or noise, respectively, cortisol levels were comparable between men and women or higher among women. We have also examined cortisol levels among those with problem eating, gambling, or posttraumatic stress disorder (PTSD). Women with restrained eating habits have higher basal cortisol levels than do women without restrained eating habits. Pathological gamblers have more aberrant stress response to gambling stimuli than do recreational gamblers, and these effects are more prominent among men than women. Men who have motor vehicle accident related PTSD, demonstrate more aberrant cortisol function, than do their female counterparts. Although these sex differences in cortisol seem to vary with type of stress exposure and/or pathophysiological status of the individual, other hormones may influence cortisol response. To address this, cortisol levels among boys and girls with different stress-related experiences, will be the subject of future investigation.

Fluoxetine-induced decrements in sexual responses of female rats and hamsters are reversed by 3α,5α-THP.

INTRODUCTION: Sexual dysfunction, as a result of selective-serotonin reuptake inhibitor (SSRI) treatment among women, is relatively common and is a factor in medication compliance. The mechanisms that underlie these side-effects of SSRIs are not well-understood. SSRIs can alter activity of catabolic enzymes that are involved in progesterone's conversion to 5 α-pregnan-3 α-ol-20-one (3 α,5 α-THP). 3 α,5 α-THP plays a key role in female reproductive physiology and behavior. AIMS: This study aimed to determine whether 3 α,5 α-THP, in the midbrain ventral tegmental area (VTA) may be a potential mechanism for fluoxetine's reduction in sexual responding of female rodents. We hypothesized that if fluoxetine induces decrements in sexual responding in part through actions of 3 α,5 α-THP, then fluoxetine will inhibit sexual receptivity concomitant with reducing 3 α,5 α-THP levels, effects which can be reversed by 3 α,5 α-THP administration. METHODS: Experiment 1 investigated effects of acute systemic fluoxetine [20 mg/kg intraperitoneal (IP)] and/or 3 α,5 α-THP [500 µg, subcutaneous (SC)] administration on sexual responding of ovariectomized, hormone-primed rats. Experiment 2 examined effects of 3 α,5 α-THP administration to the midbrain VTA (100 ng) on fluoxetine-induced decrements in lordosis of ovariectomized, hormone-primed rats and hamsters. MAIN OUTCOME MEASURES: Sexual responding was determined in rats and hamsters. For rats, the percentage of times that the lordosis response occurred following mounting by a sexually-vigorous male (lordosis quotients) was utilized. For hamsters, lateral displacement, the pelvic movement that females will make to facilitate intromissions by a male hamster, was utilized. RESULTS: Fluoxetine significantly reduced lordosis, and this was reversed SC 3 α,5 α-THP. Intra-VTA 3 α,5 α-THP attenuated fluoxetine's detrimental effects on lordosis quotients and lateral displacement of rats and hamsters, respectively. CONCLUSIONS: Thus, fluoxetine's effects to disrupt female sexual responses may involve its effects on progestogens in the midbrain VTA.

Raloxifene and/or estradiol decrease anxiety-like and depressive-like behavior, whereas only estradiol increases carcinogen-induced tumorigenesis and uterine proliferation among ovariectomized rats.

Controversy surrounds the efficacy and safety of 17beta-estradiol (E2)-mimetic therapies to women for treatment of menopausal symptoms. An important question is the nature of the trophic actions of E2-mimetics in the brain for behavioral processes versus in the periphery for beneficial effects related to osteoporosis, or unwanted proliferative effects in the reproductive tissues, such as mammary glands and uterus. Of recent interest are the effects of selective estrogen receptor modulators, which can have tissue specific actions, for these processes. In the present study, the effects were determined of E2 alone, or co-administered with a selective estrogen receptor modulator, raloxifene, for anxiety-like, depression-like, and trophic peripheral effects in ovariectomized rats that were exposed to a chemical carcinogen (7,12-dimethylbenz(a)anthracene), or not. Once per week, rats were administered vehicle, E2 (0.09 mg/kg) and/or raloxifene (1 mg/kg) subcutaneously 44-48 h before testing in a positive control, E2-dependent behavior (lordosis), depression (forced swim test), and anxiety (elevated plus maze) behavioral assays. In addition to behavioral endpoints, incidence and number of tumors, and tumor, pituitary gland, and uterine weight 14 weeks after carcinogen-exposure, and weekly hormone treatments, were analyzed. Rats administered 7,12-dimethylbenz(a)anthracene had an increased number and size of tumors, compared with vehicle treatment. E2 + raloxifene increased the number of tumors. Administration of E2 or E2 +raloxifene, but not raloxifene alone, increased pituitary and uterine weight, compared with vehicle administration. E2 or E2 + raloxifene, but not raloxifene alone, also increased the incidence of lordosis and reduced the depression-like behavior in the forced swim test (i.e. decreased time spent immobile) compared with vehicle administration. However, administration of E2 or raloxifene reduced anxiety behavior in the elevated plus maze (i.e. increased time spent on the open arms of the maze), compared with vehicle treatment. Together these data show that E2 and/or raloxifene can have some effects to alter the behavior of ovariectomized rodents, depending upon the task. As well, E2, with or without raloxifene, can also have clear trophic actions in peripheral tissues, such as carcinogen-induced tumors, uterus, and pituitary glands.

Conjugated equine estrogen, with medroxyprogesterone acetate, enhances formation of 5alpha-reduced progestogens and reduces anxiety-like behavior of middle-aged rats.

The mechanisms by which progestogens influence affective behaviors in females are poorly understood despite clear changes in mood/affect that are associated with their decline during menopause. Conjugated equine estrogens (CEE), with or without medroxyprogesterone acetate (MPA), are commonly prescribed hormone-replacement, but there is heterogeneity in responses to these pharmacotherapies. One way in which these compounds differ is in their capacity to potentiate metabolism of progesterone to its 5alpha-reduced products, dihydroprogesterone and 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP). This study investigated whether responses to CEE and MPA may be related to the capacity to metabolize progesterone. Middle-aged female rats that had maintained reproductive status, or those that had a decline, were administered vehicle, CEE and/or MPA. Effects on anxiety-like (open field, elevated plus maze) and social behaviors (social interaction test), and plasma and hippocampus steroid levels were determined. We hypothesized that CEE, but not MPA, would decrease anxiety-like behavior coincident with increased hippocampal metabolism of progesterone. CEE, or CEE+MPA, increased central entries in the open field and time spent on the open arms of the plus maze, but did not alter social interaction of rats that had maintained reproductive status. CEE and/or CEE+MPA increased E2 and 3alpha,5alpha-THP in plasma and/or hippocampus of rats, but MPA increased levels of dihydroprogesterone in the hippocampus of rats with declining reproductive status. Simple regressions showed that hippocampus 3alpha,5alpha-THP levels accounted for a significant proportion of the variance in anxiety-like behavior. Therefore, effects of CEE to reduce anxiety-like behavior of middle-aged rats may be owing, in part, to its capacity to enhance levels of 3alpha,5alpha-THP in the hippocampus.

Salivary alpha-amylase and cortisol among pentecostals on a worship and nonworship day.

OBJECTIVES: This investigation used a biomarker of sympathetic nervous system activity novel to biocultural research to test the hypothesis that engaging in religious worship activities would reduce baseline stress levels on a non-worship day among Pentecostals. METHODS: As detailed in Lynn et al. (submitted for publication), stress was measured via salivary cortisol and α-amylase among 52 Apostolic Pentecostals in New York's mid-Hudson Valley. Saliva samples were collected at four predetermined times on consecutive Sundays and Mondays to establish diurnal profiles and compare days of worship and non-worship. These data were reanalyzed using separate analyses of covariance on α-amylase and cortisol to control for individual variation in Pentecostal behavior, effects of Sunday biomarkers on Monday, and other covariates. RESULTS: There was a significant decrease in cortisol and an increase in α-amylase on a non-worship day compared with a service day. Models including engagement in Pentecostal worship behavior explained 62% of the change in non-service day cortisol and 73% of the change in non-service day α-amylase. CONCLUSIONS: Engagement in Pentecostal worship may be associated with reductions in circulatory cortisol and enhancements in α-amylase activity.

Mating Enhances Expression of Hormonal and Trophic Factors in the Midbrain of Female Rats.

Among female rats, mating enhances neurosteroid formation in the midbrain ventral tegmental area (VTA; independent of peripheral steroid-secreting glands, ovaries, and adrenals). The sources/targets for these actions are not well understood. In Experiment 1, proestrous rats engaged in a mating paradigm, or did not, and the midbrains had been assessed via the Affymetrix rat genome microarrays. In Experiment 2, the influence of gonadal and adrenal glands on the expression of these genes was assessed in rats that were proestrous, ovariectomized (OVX), or OVX and adrenalectomized (ADX). The microarrays revealed 53 target genes that were significantly up-regulated (>2.0-fold change) in response to mating. Mating significantly enhanced the midbrain mRNA expression of genes involved in hormonal and trophic actions: Gh1, S100g, and Klk1b3 in proestrous, but not OVX and/or ADX, rats; Fshb in all but OVX/ADX rats; and lutenizing hormone ß and thyroid-stimulating hormone (TSH) ß in all rats. Thus, mating enhances midbrain gene expression independent and dependent of peripheral glands.

Learning and the Lifespan: What's Sex Got to Do With It?

Engagement in sexual behavior can impact neurosteroidogenesis, in particular production of the prohormone testosterone (T) and likely its subsequent metabolism to 5α-androstane-3α-17ß-Diol (3α-Diol) or aromatization to estradiol (E2). Androgens and their metabolites vary across the lifespan and impact many behaviors, including cognition, anxiety, and sexual behavior. Thus, we hypothesized that mating may alter cognitive performance via androstane neurosteroids in an age- and experience-dependent manner. We first investigated if exposure to mating during memory consolidation could enhance performance in the novel object recognition task (NOR). Male rats were trained in NOR and then immediately exposed to mating-relevant or control stimuli. Following a 4 h inter-trial interval (ITI), male rats were tested for object memory. Male rats that were exposed to a receptive female during the ITI had better performance in NOR. We then investigated if these effects were due to novelty associated with mating. Male rats were exposed to mating-relevant stimuli and identified as sexually responsive (SR) or sexually non-responsive (SNR) based on a median split of engagement in mating with the stimulus female. We found that a brief history (10 min session daily for five consecutive days) of sexual history substantially influenced performance in the NOR task, such that SR males had better performance in the NOR task, but only when presented with the opportunity to mate during the ITI. As T levels substantially decrease with age in male rodents, we investigated whether the effects of long-term sexual experience (10 months) influenced neurosteroids and NOR performance in mid-aged (12 months old) males. Mid-aged SR males maintain neural T; however, they have decreased neural E2 and decreased cognitive performance at 12 months compared to mid-aged SNR rats. In sexually experienced rats, those with better cognitive performance had greater levels of T metabolites (e.g., 3α-Diol in mated SR males, E2 in mid-aged SNR rats). While naïve males that were mated during the ITI had better cognitive performance, T metabolites were decreased compared to controls. These findings suggest that T metabolites, but not the prohormone, may influence learning dependent on sexual proclivity, experience, and proximate opportunity to mate.

Progesterone's Effects on Cognitive Performance of Male Mice Are Independent of Progestin Receptors but Relate to Increases in GABAA Activity in the Hippocampus and Cortex.

Progestogens' (e.g., progesterone and its neuroactive metabolite, allopregnanolone), cognitive effects and mechanisms among males are not well-understood. We hypothesized if progestogen's effects on cognitive performance are through its metabolite allopregnanolone, and not actions via binding to traditional progestin receptors (PRs), then progesterone administration would enhance performance in tasks mediated by the hippocampus and cortex, coincident with increasing allopregnanolone concentrations, brain derived neurotrophic factor (BDNF) and/or muscimol binding of PR knock out (PRKO) and wild-type PR replete mice. Experiment 1: Progesterone (4 mg/kg, subcutaneously (SC; n = 12/grp), or oil vehicle control, was administered to gonadally-intact adult male mice PRKO mice and their wild-type counterparts and cognitive behaviors in object recognition, T-maze and water maze was examined. Progesterone, compared to vehicle, when administered post-training increased time investigating novel objects by the PRKO and wild-type mice in the object recognition task. In the T-maze task, progesterone administration to wild-type and PRKO mice had significantly greater number of spontaneous alternations compared to their vehicle-administered counterparts. In the water maze task, PRKO mice administered vehicle spent significantly fewer seconds in the quadrant associated with the escape platform on testing compared to all other groups. Experiment 2: Progesterone administered to wild-type and PRKO mice increased plasma progesterone and allopregnanolone levels (n = 5/group). PRKO mice had higher allopregnanolone levels in plasma and hippocampus, but not cortex, when administered progesterone and compared to wild-type mice. Experiment 3: Assessment of PR binding revealed progesterone administered wild-type mice had significantly greater levels of PRs in the hippocampus and cortex, compared to all other groups (n = 5/group). Wild-type mice administered progesterone, but not vehicle, had increased BDNF levels in the hippocampus, but not the cortex, compared to PRKOs. Wild-type as well as PRKO mice administered progesterone experienced significant increases in maximal GABAA agonist, muscimol, binding in hippocampus and cortex, compared to their vehicle-administered counterparts. Thus, adult male mice can be responsive to progesterone for cognitive performance, and such effects may be independent of PRs trophic actions of BDNF levels in the hippocampus and/or increases in GABAA activity in the hippocampus and cortex.