Estrogen imprinting compromises male sexual behavior and affects the number of androgen-receptor-expressing hypothalamic neurons†

Neonatal exposure to high-dose 17β-estradiol (E2) affects the morphology and physiology of sex and accessory sex organs in the long term. In this study, we examined the effects of E2 imprinting on male sexual behavior, fertility, and the number of androgen receptor (AR)-expressing cells in the hypothalamus. E2-treated males showed copulatory behavior represented by mounts and/or intromissions, demonstrating the preservation of aspects of male behavior. They had slightly increased latency for first intromission and a reduced number of ejaculations, associated with a 50% reduction in the fertility index. AR expression in the hypothalamus was assessed by RT-PCR, western blotting, and immunohistochemistry. Treated rats had a significantly lower ventral prostate (VP) weight, demonstrating the efficacy of the treatment. The AR mRNA and protein content in the hypothalamus of E2-treated animals was reduced to the levels of females. AR-expressing cell counts in the ventromedial, anterior medial preoptic, paraventricular nuclei, and preoptic areas were different from control males, and similar to those of females. In conclusion, E2 imprinting resulted not only in ill-developed sexual organs, but also affected sexual behavior, resulting in a female-type hypothalamus, at least with respect to the abundance of AR mRNA and protein and the number of AR-expressing cells in important regions/tracts.

Orchidectomy enhances the expression of endothelin-1 and ETB receptors in rat portal vein

Functional studies have shown that orchidectomy increases the effects of phenylephrine on rat portal veins, but that it is completely prevented in the presence of both ETA and ETB receptor antagonists. Although it suggests the involvement of endothelin-1 (ET-1), the local production of this vasoactive peptide has not been directly quantified in portal veins. Therefore, the aim of the present study was to verify if orchidectomy increases the local expression of ET-1 as well as ETA and ETB receptors in the rat portal vein. Indeed, the genic expression of ET-1, ETA and ETB receptors in rat portal veins taken from control (CONT), orchidectomized (ORX) and ORX plus testosterone-replacement therapy (ORX + T) animals were determined by Real Time RT-PCR. The results showed that orchidectomy induced a significant increment in genic expression of ET-1 and ETB receptors in the rat portal veins, which was completely reversed by testosterone replacement treatment. In conclusion, the results suggest that orchidectomy increases the production of ET-1 in the rat portal vein and that, at least partially, it may be related to the previously reported elevation of responses to phenylephrine.

Prenatal testosterone supplementation alters puberty onset, aggressive behavior, and partner preference in adult male rats

The objective of this study was to investigate whether prenatal exposure to testosterone (T) could change the body weight (BW), anogenital distance (AGD), anogenital distance index (AGDI), puberty onset, social behavior, fertility, sexual behavior, sexual preference, and T level of male rats in adulthood. To test this hypothesis, pregnant rats received either 1 mg/animal of T propionate diluted in 0.1 ml peanut oil or 0.1 ml peanut oil, as control, on the 17th, 18th and 19th gestational days. No alterations in BW, AGD, AGDI, fertility, and sexual behavior were observed (p > 0.05). Delayed onset of puberty (p < 0.0001), increased aggressive behavior (p > 0.05), altered pattern of sexual preference (p < 0.05), and reduced T plasma level (p < 0.05) were observed for adult male rats exposed prenatally to T. In conclusion, the results showed that prenatal exposure to T was able to alter important aspects of sexual and social behavior although these animals were efficient at producing descendants. In this sense more studies should be carried to evaluated the real impact of this hormonal alteration on critical period of sexual differentiation on humans, because pregnant women exposed to hyperandrogenemia and then potentially exposing their unborn children to elevated androgen levels in the uterus can undergo alteration of normal levels of T during the sexual differentiation period, and, as a consequence, affect the reproductive and behavior patterns of their children in adulthood.

Ejaculatory dysfunction in streptozotocin-induced diabetic rats: the role of testosterone

Hyperglycemic and hypoinsulinemic states caused by diabetes mellitus are usually related to some type of sexual dysfunction, resulting in infertility in humans and experimental models, mostly due to their effects on ejaculatory function. This study aimed to evaluate the possible role of testosterone in the restoration of normal ejaculatory function in diabetic rats. Male Wistar rats were randomly allocated into 3 experimental groups: control, diabetic (streptozotocin), and diabetic with testosterone supplementation (streptozotocin plus testosterone). The following parameters were assessed at the end of the experiment: body weight, circulating testosterone levels, number of spermatozoa ejaculated in the uterus through natural mating, and weight and in vitro isometric contractions of the vas deferens. Diabetic rats showed reduced plasma testosterone levels and ejaculatory dysfunction as observed by a lack in the spermatozoa ejaculated into the uterus of receptive females. In these diabetic rats, no difference was observed in the sensitivity of the vas deferens to norepinephrine, with or without the presence of the cocktail (cocaine plus propranolol). In spite of this, an increased sensitivity to methoxamine through the α1-adrenoceptor was observed. Testosterone supplementation did not restore these parameters to control values.We conclude that, in this experimental model, the lack of testosterone was not directly related to the diabetes-induced ejaculatory dysfunction.

Orchidectomy enhances the effects of phenylephrine in rat isolated portal vein

1. Orchidectomy results in long-term testosterone deprivation similar to that observed in male clinical pathologies, such as hypogonadism and age-related reductions in plasma testosterone concentrations. Although the vascular effects of these sorts of hormone deprivations are known in arteries, they have not been studied to the same extent in veins. 2. The aim of the present study was to determine the effect of orchidectomy, with or without subsequent testosterone replacement (started 23 days after orchidectomy; 10 mg/kg, i.m., testosterone propionate once every 5 days for 3 weeks), on responses of rat isolated portal veins and vena cavae to exogenous phenylephrine (PE). Isolated vessels were mounted in an organ bath and concentration-response curves constructed to PE (10(-10)-10(-4) mol/L), endothelin (ET; 10(-10)-10(-5) mol/L) and KCl (10(-2)-1.2 x 10(-1) mol/L; as a control). 3. Orchidectomy had no effect on contractile responses of either the portal vein or vena cava to KCl. However, orchidectomy enhanced the maximum response (R(max)) of the portal vein, but not the vena cava, to PE. Testosterone replacement had no effect on these responses. The effects of orchidectomy on the R(max) to PE in portal veins were not altered by the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester (10(-4) mol/L) alone or combined with 10(-5) mol/L indomethacin (a non-selective cyclo-oxygenase inhibitor), but they were abolished following treatment of isolated vessels with the ET(A) and ET(B) receptor antagonists BQ-123 and BQ-788 (both at 10(-6) mol/L). Orchidectomy did not alter portal vein responses to the application of exogenous ET. 4. The results of the present study indicate that orchidectomy-induced decreases in plasma testosterone can increase the venoconstrictor effects of PE on the portal vein and that this effect involves activation of both ET(A) and ET(B) receptors by locally produced ET.

Multiple effects of sibutramine on ejaculation and on vas deferens and seminal vesicle contractility

Sibutramine is an inhibitor of norepinephrine and 5-HT reuptake largely used in the management of obesity. Although a fairly safe drug, postmarketing adverse effects of sibutramine were reported including abnormal ejaculation in men. This study investigates the effects of sibutramine on ejaculation and vas deferens and seminal vesicle contractility. Adult male rats received sibutramine (5; 20; or 50 mg kg(-1), ip) and after 60 min were exposed to receptive females for determination of ejaculation parameters. The vasa deferentia and seminal vesicles of untreated rats were mounted in isolated organ baths for recording of isometric contractions and HEK293 cells loaded with fluorescent calcium indicator were used to measure intracellular Ca(2+) transients. Sibutramine 5 and 20 mg kg(-1) reduced ejaculation latency whereas 50 mg kg(-1) increased ejaculation latency. Sibutramine 3 to 30 microM greatly increased the sensitivity of the seminal vesicle and vas deferens to norepinephrine, but at concentrations higher than 10 microM there were striking depressions of maximal contractions induced by norepinephrine, carbachol and CaCl(2). In HEK293 cells, sibutramine 10 to 100 microM inhibited intracellular Ca(2+) transients induced by carbachol. Depending on the doses, sibutramine either facilitates or inhibits ejaculation. Apart from its actions in the central nervous system, facilitation of ejaculation may result from augmented sensitivity of smooth muscles to norepinephrine while reductions of intracellular Ca(2+) may be involved in the delayed ejaculation observed with high doses of sibutramine.

Semen parameters, fertility and testosterone levels in male rats exposed prenatally to betamethasone

The present study investigated the long-term effects of prenatal betamethasone exposure on sperm quality and count, fertility and plasma testosterone levels in adult male rats. Pregnant rats received 0.1 mg kg–1 betamethasone on Days 12, 13, 18 and 19 of pregnancy. This treatment impaired sperm quality, sperm production, fertility and plasma testosterone levels in adult male offspring compared to the control group. Thus, the results of the present study indicate that the long-term effects of prenatal betamethasone exposure may be deleterious to offspring. The consequent decrease in testosterone production during adulthood, in association with damaged semen parameters, may explain for the observed decrease in the capacity of adult male offspring to themselves generate viable descendants.

Effects of maternal exposure to an aromatase inhibitor on sexual behaviour and neurochemical and endocrine aspects of adult male rat

The present study examined the effects of letrozole exposure during brain sexual differentiation on endocrine, behavioural and neurochemical parameters in male rat descendants. Pregnant female rats received 1 mg kg(-1) day(-1) letrozole or vehicle by oral gavage on gestational Days 21 and 22. Exposure to letrozole reduced anogenital distance in males on postnatal Day (PND) 22. At adulthood (PND 75), plasma testosterone levels and hypothalamic dopaminergic activity were increased, but sexual competence was impaired, because fewer successful sexual behaviours (mount, intromission and principally ejaculation) were observed. The impairment of reproductive function by prenatal exposure to an aromatase inhibitor reinforces the importance of adequate oestrogenic activity during perinatal sexual differentiation for complete masculinisation of the hypothalamus.

Fenvalerate, a pyrethroid insecticide, adversely affects sperm production and storage in male rats

The aim of this study was to investigate the potential estrogenic activity of fenvalerate by examining reproductive and fertility capabilities in Wistar rats. Adult male animals were treated for 30 d with 20 or 40 mg/kg/d fenvalerate or corn oil (vehicle) by oral gavage. Further, a possible estrogenic activity of fenvalerate (0.4, 1, 4, 8, or 40 mg/kg) was tested after a 3-d treatment of immature female rats using the uterotrophic assay. Exposure to the higher dose of fenvalerate was toxic to testis and epididymis as shown by a decrease in the absolute weights and sperm counts in both organs. Although the sperm counts were reduced, the fertility and sexual behavior were similar in control rats and rats treated with 40 mg/kg pesticide. Fenvalerate did not exert estrogenic activity in vivo at the tested doses. Data suggest that fenvalerate treatment in this study failed to compromise fertility, possibly due to enhanced reproductive capacity in rodents compared to humans.

Antisperm antibodies in infertile men and their correlation with seminal parameters

Aim:  Antisperm antibodies (ASA) in males cause the autoimmune disease 'immune infertility'. The present study intended to detect the presence of ASA and their incidence in men with unexplained infertility, as well as to evaluate the correlation between the presence of ASA and semen parameter alterations. Methods:  Blood and sperm assessment were collected to carry out a direct and indirect mixed antiglobulin reaction (MAR) test and semen analysis in infertile and fertile men from the University Hospital of the Faculty of Medicine, Sao Paulo State University, Sao Paulo. Results:  In the MAR test, 18.18% of infertile men were positive for ASA. In fertile men, no positivity was found. A significant correlation between the presence of ASA with an increased white blood cell count plus a decreased hypoosmotic swelling test result was observed. Conclusions:  The results indicate that ASA are involved in reduced fertility. It is not ASA detection per se that provides conclusive information about the occurrence of damage to fertility. The correlation between infertility and altered seminal parameters reinforce the ASA participation in this pathology. (Reprod Med Biol 2007; 6: 33-38).

Impairment of adult male reproductive function in rats exposed to ethanol since puberty

The objective of this work was to evaluate reproductive function in adult male rats exposed to ethanol since puberty. Male Wistar rats, 50 days old, received a liquid diet with 36% of the daily calories derived from ethanol or an isocaloric control diet for 55 days. The ethanol treatment impaired sexual behavior and only 22% of these rats reached ejaculation. The fertility of ethanol-treated animals was significantly reduced, mainly after natural mating. Serum testosterone levels, daily sperm production and sperm count in the epididymis were also significantly diminished after ethanol treatment, associated with an acceleration of the sperm transit time in the cauda epididymidis, decrease in sperm motility and increased percentage of abnormal shaped sperm cells. The results showed that chronic consumption of ethanol beginning at puberty impairs the reproductive function of adult male rats.

Neuroendocrine and reproductive aspects of adult male rats exposed neonatally to an antiestrogen

The present study was designed to investigate the effects of a single dose of an estrogen antagonist-clomiphene-during neonatal life, on later neuroendocrine system and reproductive performance. Immediately after birth, male pups received clomiphene citrate (s.c.). At adulthood, although testosterone levels and wet weights of reproductive organs were not altered, the treatment induced an increased number of spermatozoa and a delay in the transit time in the cauda epididymis. Additionally, there was impairment of sexual behavior evidenced by a delay in the latencies to the first mount and first intromission. Treated rats also showed decreased dopaminergic and serotonergic neurotransmissions in the hypothalamus and decreased dopaminergic neurotransmission in the striatum. The decreased dopaminergic activity could be related to the lower sexual motivation observed. These results indicate the necessity of preventing exposure to drugs that may impair sexual differentiation, which can compromise later mating success as well as the capacity to generate descendants.

Reproductive and sexual behavior changes in male rats exposed perinatally to picrotoxin

Previous studies in rats suggested that picrotoxin, a GABA(A) receptor antagonist, may cause long-term changes in male reproductive physiology and behavior in rats exposed during prenatal and postnatal periods. The present study has further examined this phenomenon. Wistar rat dams were dosed subcutaneously with 0.75 mg/kg picrotoxin in saline, or vehicle alone, during the perinatal period (day 19 of gestation, immediately after parturition, and once a day during the first 5 days of lactation). Birth weight and sexual maturation of pups were unchanged; however, plasma testosterone levels and sexual behavior was altered in male offspring. Although fertile, these males showed altered mating behavior in terms of a decrease in the mean number of mounts during a 30-min observation period with normal females. Some showed homosexual behavior when castrated and pretreated with exogenous estrogen. These findings suggest that perinatal exposure to picrotoxin alters sexual dimorphism in the developing rat brain, manifesting as altered reproductive performance and sexual behavior of males.

Sexual behavior, neuroendocrine, and neurochemical aspects in male rats exposed prenatally to stress

The present study was designed to examine some short- and long-term effects of maternal restraint stress--during the period of sexual brain differentiation--on reproductive and endocrine systems, sexual behavior, and brain neurotransmitters in male rat descendants. Pregnant rats were exposed to restraint stress for 1 h/day from gestational days (GDs) 18 to 22. Prenatal stress did not influence the wet weight of sexual organs and the quantity of germ cells in adult male pups; however, these animals showed reduced testosterone levels, delayed latency to the first mount and first intromission, and also decreased number of ejaculations. Additionally, there was an increase in the dopamine and serotonin levels in the striatum. Our results indicate that prenatal stress had a long-term effect on neurotransmitter levels and sexual behavior. In this sense, reproductive problems caused by injuries during the fetal period can compromise the later success of mating as well as the capacity to generate descendants.

A simple high-performance liquid chromatography assay for on-line determination of catecholamines in adrenal gland by direct injection on an ISRP column

In the present research, assays were improved for the determination of catecholamines in adrenal gland. High-performance liquid chromatography with electrochemical detection was employed for quantitative analysis. The method involved direct injection of acid extract on to a serum albumin dimethylocadecyl-silane (HSA-C18) and the utilization of phosphate buffer (pH = 3.0): methanol (97:3 v/v), 0.025 g heptanosulfonic acid and 0.0025 g EDTA as mobile phase. The detection was obtained using an electrochemical detector L-ECD-6A-Shimadzu with a potential of the 85 mV. Identification was based on retention time. Quantification was performed by automatic peak-area determination. The detection limit is equal to 0.5 ng ml(-1). The HPLC method with electrochemical detection proposed here permits good separation of catecholamines in samples of adrenal gland from rats. The method has various advantages: fast, high precision and good selectivity and do not require sample treatment. The immobilization stress during 5 min did not provoke alteration in catecholamines contains in rat adrenal gland, due to the short time of the stress exposure. This study shows that the catecholamines (norepinephrine and epinephrine) adrenal increased significantly after the acute immobilization stress during 30 min as compared to control group. This increase probably is due to the emotional component of the immobilization stress. In conclusion, our studies suggest an effective participation of the adrenal glands to maintain the homeostasis of organism to the stressful conditions.

Reproductive aspects in female rats exposed prenatally to hydrocortisone

We investigated the effects of hydrocortisone during the prenatal period and its later repercussion on reproductive aspects of female rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of pregnancy. Although the present study was not intended to identify mechanisms of toxicity, the treatment with hydrocortisone in the last period of pregnancy presented no signs of toxicity. The efficacy of the hydrocortisone in reducing the adrenal wet mass and plasma corticosterone levels immediately after delivery in both the treated mothers and in respective pups at birth may indicate impairment of the hypothalamus-pituitary-adrenal axis. In addition, the treatment with hydrocortisone did not interfere in the development of the female descendants until puberty. However, it affected the estrous cycle and fertility. Probably, the prenatal exposure to corticosteroids had altered at least partially the hypothalamus-pituitary-gonadal axis, resulting in the damages observed in adult life. These results indicate that the use of the hydrocortisone at a dose that apparently does not endanger the neonate led to undesirable effects in the adult reproductive phase, resulting in later deleterious alteration of the reproductive physiology in female rats.

Changes in norepinephrine and epinephrine concentrations in adrenal gland of the rats submitted to acute immobilization stress

Catecholamines act as neurotransmitters and hormones. Studies conducted to understand the synthesis and metabolism of these monoamines during stress have been the main concern of many authors. This work proposes to investigate the time course of changes in epinephrine and norepinephrine concentration in adrenal gland obtained from rats submitted to acute immobilization stress. The results of the present study indicate that acute immobilization stress during 5 and 15 min did not provoke changes in epinephrine and norepinephrine concentrations in adrenal gland in relation to the control group. Such results are justified due to the short time of the stress, showing that the stress did not provoke physiological alteration. The epinephrine and norepinephrine concentrations in adrenal gland increased significantly after the immobilization session in stressed groups during 30 and 50 min as compared to control group. This increase probably is due to the emotional component of the immobilization stress. In this way, we suggested that the immobilization stress provoke increase in the biosynthesis of catecholamines in the adrenal gland from rats. However, the results shows that a maximum increase is reached at 30 min of immobilization stress and then a decrement of catecholamines levels starts at 50 min of the experimental design. This decline in catecholamines level may be consequence of adaptation to stress situations, an increase of the activity of the uptake systems and/or metabolization of catecholamines. In conclusion, these results suggest an effective participation of the adrenal glands to maintain the homeostasis of organism to the stressful conditions.

Effects of prenatal hydrocortisone acetate exposure on fertility and sexual behavior in male rats

The aim of the present study was to investigate the effects of hydrocortisone during the prenatal period and its later repercussions on the fertility and sexual behavior of male rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of gestation. Decreased body weight and no alteration in anogenital distance were observed in male offspring. Adulthood, presented reductions of body weight, plasma testosterone levels, and seminal-vesicle wet weight without secretion as well as no alteration in the wet weights of the testes, epididymis, and seminal vesicle with secretion in the treated group. Males exposed to hydrocortisone during the prenatal period were able to mate with normal females, which became pregnant but exhibited an increased number of post-implantation losses. In spite of this, these treated males exhibited decreased male sexual behavior and the appearance of female sexual behavior after these male rats were castrated and pretreated with exogenous estrogen. These results indicate that exposure to hydrocortisone in the later stages of pregnancy may have a long-term effect on the fertility and sexual behavior of male rats, suggesting an incomplete masculinization and defeminization of the central nervous system.

Pharmacological evidence that methylene blue inhibits noradrenaline neuronal uptake in the rat vas deferens

We report that the classical guanylate cyclase inhibitor methylene blue (MB, 1 microM or 10 microM), but not the selective guanylate cyclase inhibitor 1H-[1,2,4]oxidazolo[4,3-a]quinoxalin-1-one (1 microM) or nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (100 microM), causes a shift to the left in the concentration-response curve for noradrenaline in the isolated rat vas deferens preparations. The main objective of our study was to investigate the pharmacological mechanism by which MB increases the sensitivity of the rat vas deferens to noradrenaline. According to the presented results, MB did not change rat vas deferens sensitivity to methoxamine or noradrenaline in the presence of desipramine (0.1 microM). The pre-contracted rat vas deferens relaxation induced by isoproterenol was also not significantly changed by MB (1 microM). Thus, we suggest that MB increases rat vas deferens sensitivity through neuronal uptake inhibition without interfering in either the nitrergic mechanism or guanylate cyclase activity.

Cholinergic responses of seminal vesicles isolated from rats exposed perinatally to hydrocortisone

This study was performed in order to investigate the cholinomimetic response of seminal vesicles isolated from rats treated with hydrocortisone acetate during perinatal life. At the adult phase, the body weight and the wet weight of the seminal vesicle of these animals were unchanged. However, these male rats exhibited a significant reduction in plasma testosterone concentration. A significant increase in the sensitivity of the seminal vesicle to acetylcholine was also observed. Despite this, there was a significant reduction in the maximum contractile response of the organ to this transmitter. These results indicate that exposure to hydrocortisone during the critical period of brain sexual differentiation has a long-term effect on testosterone production of male rats. In addition, physiological levels of cortisone in perinatal life are also essential to support the contractile response pattern of the seminal vesicle to acetylcholine in adult life, probably crucial to the reproductive process.

Effects of neonatal clomiphene citrate on fertility and sexual behavior in male rats

In order to investigate the participation of estrogen during the period of brain sexual differentiation, male rats were treated with clomiphene citrate in the neonatal phase. Fertility and sexual behavior were assessed during adult life. Sexual maturation, body weight, and wet weight of the testes were unchanged. Although the adult male rats treated with clomiphene in the neonatal phase presented a significant reduction in the frequency of mounts, 90% of these rats were able to mate with normal females, which became pregnant. However, these females exhibited a significantly increased number of pre- and post-implantation losses. When these adult male rats were castrated and received estrogen, 60% presented female sexual behavior (receptive behavior and acceptance of mount). Thus, treatment of pups with clomiphene immediately after birth has a long-term effect on the reproductive physiology and sexual behavior of male rats.

Neonatal inhalatory anesthetic exposure: reproductive changes in male rats

We investigated the effects of an inhalatory anesthetic (ethyl ether) during the neonatal period of brain sexual differentiation on the later fertility and sexual behavior of male rats. Animals were exposed to ethyl ether immediately after birth. At adulthood, body weight, testes wet weight, and plasma testosterone levels were not affected; however, neonatal exposure to ether showed alterations on male fertility: a decrease in the number of spermatids and spermatozoa, an increase in the transit time of cauda epididymal spermatozoa and a decrease in daily sperm production. An alteration of sexual behavior was also observed: decreased male sexual behavior and appearance of homosexual behavior when the male rats were castrated and pretreated with exogenous estrogen. Probably, the ether delayed or reduced the testosterone peak of the sexual differentiation period, altering the processes of masculinization and defeminization of the hypothalamus. Our results indicate that perinatal exposure to ethyl ether during the critical period of male brain sexual differentiation, acting as endocrine disruptors, has a long-term effect on the fertility and sexual behavior of male rats, suggesting endocrine disruption through incomplete masculinization and defeminization of the central nervous system.

Acute swimming stress induces changes in noradrenergic mechanisms in order to maintain the response pattern of the rat vas deferens to norepinephrine

This study investigated mechanisms involved in the maintenance of the functional response pattern of the postjunctional alpha(1)-adrenoceptor in vas deferens isolated from rats submitted to acute swimming stress. The plasma corticosterone levels increased approximately three times after the swimming stress in the nontreated rats as well as after swimming stress in the rats pretreated with desipramine (DMI), yohimbine (YO), or DMI with YO. No alteration was detected in the sensitivity to norepinephrine (NE) in the vasa deferentia from the stressed rats or stressed rats treated with DMI or DMI with YO, in relation to their respective control. However, when the vasa deferentia were previously incubated with DMI, a reduction in sensitivity to NE in organs from stressed rats was observed. Vasa deferentia excised from rats pretreated with YO before the swimming stress showed an increase in postjunctional alpha(1)-response that was abolished by prazosin (PZ). Thus, the neuronal uptake, the prejunctional alpha(2)-adrenoceptors (mediating prejunctional inhibition), the occupancy and functional response of the postjunctional alpha(1)-adrenoceptors, and the emotional stress component were very important for the determination of the noradrenergic response pattern in vas deferens from rats submitted to acute swimming stress.

Reproductive changes in male rats treated perinatally with an aromatase inhibitor

The effects of maternal exposure to aromatase inhibitor during the perinatal period of sexual brain differentiation were studied. The fertility was assessed in adult, male rat offspring of aromatase inhibitor-treated dams. The following results were obtained: (1) Sexual maturation, body weight, and wet weights of testis, pituitary, seminal vesicle, ventral prostate, and levatori ani muscle were unchanged at adult life. (2) Fifty percent of the animals were able to mate with normal females, which became pregnant but exhibited an increased number of preimplantation loss. (3) There was a decrease in the number of spermatozoa found in the testes and in the daily sperm production. (4) Of those, 25% of the male rats treated with aromatase inhibitor did not present male sexual behavior, showing female behavior when pretreated with estrogen. These results indicate that perinatal exposure to aromatase inhibitor during the critical period of male brain sexual differentiation has a long-term effect on the reproductive physiology and behavior of male rats.