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Journal Article 2015; 36(2): 178-182 PubMed PMID: 26071589 Citation  Keywords:  Animals, Animals, Newborn, Aromatase:genetics, Brain:metabolism, Estrogen Receptor alpha:genetics, Female, Fetus, Hypothalamus:metabolism, Mice, Mice, Inbred C57BL, Mice, Knockout, RNA, Messenger:metabolism,.   

OBJECTIVES: Local estrogen production in the brain regulates critical functions including neuronal development, gonadotropin secretion and sexual behavior. In the mouse brain, a 36 kb distal promoter (l.f) regulates the Cyp19a1 gene that encodes aromatase, the key enzyme for estrogen biosynthesis. In vitro, promoter l.f interacts with estrogen receptor alpha (Esr1) to mediate Cyp19a1 mRNA expression and enzyme activity in mouse hypothalamic neuronal cell lines. The in vivo mechanisms that control mammalian brain aromatase expression during fetal and adult development, however, are not thoroughly understood. Our aim was to elucidate the basis of the in vivo connection between Esr1 and Cyp19a1.

METHODS: Pregnant mice were sacrificed at gestational days 9, 11, 13, 15, 16, 19, 21 and the brain tissues of the fetuses were harvested along with five newborns at the age of postnatal day 2. Esr1KO (female) were also sacrificed and their hypothalamus were excised out. Then both fetuses and adults RNA were isolated, reverse transcribed and amplified employing primers specific for Esr1 and Cyp19a1 with Real time PCR.

RESULTS: In the fetal mouse brain, Cyp19a1 mRNA levels are inversely correlated with estrogen receptor alpha (Esr1) mRNA levels in a temporal manner. Moreover, Cyp19a1 mRNA levels increased in the hypothalamus of estrogen receptor-alpha knockout female mice (Esr1KO).

CONCLUSION: Taken together, our findings might indicate that Esr1 has crucial roles in the in vivo regulation of aromatase expression in the brain during fetal and adult life....

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Journal Article 2010; 31(5): 690-699 PubMed PMID: 21173749 Citation  Keywords:  Age Factors, Animals, Aromatase:genetics, DNA, Complementary:metabolism, Female, Fetal Development:genetics, Fetus:metabolism, Gene Expression Regulation, Developmental, Gene Expression Regulation, Enzymologic, Gestational Age, Hypothalamus:metabolism, Im.   

OBJECTIVES: An important step of sexual differentiation is the conversion of testosterone to estrogen by aromatase leading to masculinization and defeminization of the fetal brain areas crucial for normal sexual behavior and reproduction. Brain sexual differentiation occurs throughout a critical period starting from different prenatal stages depending on the species. Such period goes on from gestation day (GD) 30 to 100GD in the sheep. The fetal sheep brain is reported to aromatize androgens to estrogens at 64GD. The main goal of this work was to evaluate aromatase expression in sheep hypothalami during the whole period of sexual differentiation (35GD, 55GD, 80GD, 115GD) and whether differences may be observed depending on gestational stage and sex.

METHODS: Sections at the hypothalamic level underwent immunoperoxidase technique employing anti-aromatase and anti-androgen receptor antibodies. Samples from 35GD and 55GD were also processed with in situ hybridization using aromatase cDNA probe. Blot analyses were performed to quantify possible aromatase immunoexpression differences between sexes. For sexing, samples at 35GD and 55GD underwent DNA extraction and SRY amplification.

RESULTS: Our results revealed aromatase and androgen receptor immunoreactivity along the whole period of sexual differentiation. Both molecules were detected in many brain regions and markedly in the periventricular area. The highest aromatase and androgen receptor amounts were observed at 35GD and 55GD, when aromatase was more abundant in females than in males.

CONCLUSIONS: In conclusion, the sheep can be included among the species where aromatase is highly expressed in the hypothalamus during the whole period of sexual differentiation....

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Journal Article 2010; 31(2): 198-202 PubMed PMID: 20424589 Citation  Keywords:  Animals, Body Temperature, Fasting:adverse effects, Fibroblast Growth Factors:deficiency, Hypothalamus:metabolism, Hypothermia:etiology, Ketogenic Diet:methods, Liver:metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Motor Activity, Neuropeptide.   

BACKGROUND: Fibroblast growth factor 21 (FGF21) is a key metabolic regulator that is induced by peroxisome proliferator-activated receptor alpha (PPARalpha) activation in response to fasting. We recently reported that bezafibrate, a pan-agonist of PPARs, decreases body temperature late at night through hypothalamic neuropeptide Y (NPY) activation and others have shown that mice overexpressing FGF21 are prone to torpor.

OBJECTIVES: We examined whether FGF21 is essential for fasting-induced hypothermia using FGF21 knockout (KO) mice.

RESULTS: Acute fasting decreased body temperature late at night accompanied by the induction of hepatic FGF21 and hypothalamic NPY expression in wild-type mice. A deficiency of FGF21 affected neither fasting-induced hypothermia nor hypothalamic NPY induction. Fasting enhanced locomotor activity in both genotypes. On the other hand, a deficiency of FGF21 significantly attenuated chronic hypothermia and hypoactivity induced by a ketogenic diet (KD).

CONCLUSIONS: Our findings suggest that FGF21 is not essential for the hypothermia that is associated with the early stages of fasting, although it might be involved in the adaptive response of body temperature to chronic starvation....

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Journal Article 2008; 29(3): 341-346 PubMed PMID: 18580851 Citation  Keywords:  Adrenocorticotropic Hormone:blood, Adult, Biomarkers, Body Mass Index, Cohort Studies, Female, Glycopeptides:analysis, Humans, Hydrocortisone:blood, Hypothalamus:metabolism, Male, Middle Aged, Sex Characteristics, Stress, Psychological:metabolism, Vasopre.   

BACKGROUND: During stress, vasopressin is a potent synergistic factor of CRH as a hypothalamic stimulator of the HPA axis. The measurements of CRH and vasopressin levels are cumbersome because of their instability and short half-life. Copeptin is a more stable peptide stoichiometrically released from the same precursor molecule. The aim of our study was to compare copeptin and cortisol levels in different stress situations.

METHODS: Three groups of patients with increasing stress levels were investigated: a) healthy controls without apparent stress (n=20), b) hospitalized medical patients with moderate stress (n=25) and c) surgical patients 30 minutes after extubation, with maximal stress (n=29). In all patients we assessed cortisol and copeptin levels. Copeptin levels were measured with a new sandwich immunoassay.

RESULTS: Cortisol levels in controls were (median, IQ range, 486 [397-588] nmol/L), not significantly different as compared to medical patients (438 [371-612] nmol/L, p=0.69). Cortisol levels in surgical patients after extubation were higher (744 [645-1062] nmol/L p<0.01 vs controls and medical patients). Copeptin levels in controls were 4.3 [3.2-5.5] pmol/L, which was lower as compared to medical patients (17.5 [6.4-24.1], p<0.001) and surgical patients after extubation (67.5 [37.8-110.0] pmol/L, p<0.001). The correlation between copeptin levels and cortisol was r=0.46, p<0.001.

CONCLUSION: Copeptin is a novel marker of the individual stress level. It more subtly mirrors moderate stress as compared to cortisol values....

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Journal Article 2006; 27(1-2): 157-161 PubMed PMID: 16648812 Citation  Keywords:  Animals, Cattle, Craniocerebral Trauma:metabolism, Female, Hemorrhage:metabolism, Hypothalamus:metabolism, Immunohistochemistry, Male, Radioimmunoassay, Rest:physiology, Sex Characteristics, Stress, Psychological:metabolism, Vasopressins:blood,.   

OBJECTIVES: This study investigates antidiuretic hormone (ADH) plasma concentration in bulls and heifers at rest, after transportation stress, trauma and massive hyper-acute hemorrhage at slaughter, with special attention to differences between sexes. We also quantified ADH concentration in the ADH-producing hypothalamic area.

SETTING AND DESIGN: The study was carried out on animals at the abattoir, exploiting the routinely procedure of slaughtering to obtain the experimental stressful conditions. The control group was represented by a group of animals matched for breed, age and gender.

RESULTS: ADH plasma values suggest that transportation stress has little or no effect in heifers in contrast to bulls. In both sexes ADH release increases after open head trauma due to stunning prior to slaughter. Hemorrhagic hyper-acute stress caused by bleeding induces a rapid hundredfold rise of ADH plasma concentration that becomes diergic (physiologically different between sexes), with males showing far higher values. Females show a higher ADH concentration in the hypothalamus.

MAIN FINDING: This study points out a difference in ADH output between bulls and heifers under conditions of severe hemorrhagic stress, as produced by severing of the neck vessels at slaughtering.

CONCLUSION: Extreme stress unmasks endocrine differences in bovine ADH release that may be relevant only during specific circumstances, such as fighting....

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Journal Article 2005; 26(1): 35-38 PubMed PMID: 15726017 Citation  Keywords:  3-Oxo-5-alpha-Steroid 4-Dehydrogenase:metabolism, Animals, Aromatase:metabolism, Brain Chemistry:physiology, Catecholamines:metabolism, Chromatography, Thin Layer, Dopamine:metabolism, Female, Feminization:physiopathology, Hypothalamus:metabolism, Male, N.   

OBJECTIVES: To study the role of opioids in early postnatal changes of the hypothalamic testosterone metabolism and catecholamine content underlying feminizing effect of prenatal stress on male sexual behavior in rats.

MATERIAL AND METHODS: 10 day-old male and female offspring from mothers given naltrexone prior to daily 1-hour restraint during the last gestational week were used in the study. Aromatase and 5 alpha-reductase activities, noradrenaline and dopamine contents in the brain preoptic area and medial basal hypothalamus were studied by thin layer chromatography, radiometric and spectrofluorimetric techniques.

RESULTS: Sexual dimorphism of testosterone metabolism enzymes activity and catecholamine content in discrete brain regions of 10 day-old rat pups was found. Prenatal stress attenuated these gender-related differences. Naltrexone pre-treatment of stressed dams prevented modifying effect of prenatal stress on aromatase activity and noradrenaline content in the male preoptic area.

CONCLUSIONS: The results of the study demonstrate preventive effect of naltrexone on stress-induced alterations of testosterone aromatization and noradrenaline concentration in the developing brain preoptic area associated with neuroendocrine control of the male sexual behavior in adult rats. These findings indicate that endogenic opioids mediate detrimental effect of prenatal stress on neurochemical determinants of the brain sexual differentiation that may underlie feminization of the male sexual behavior....

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Journal Article 2002; 23(1): 33-44 PubMed PMID: 11880860 Citation  Keywords:  Adult, Aged, Arginine Vasopressin:antagonists & inhibitors, Aspartic Acid Endopeptidases:metabolism, Female, Glucocorticoids:therapeutic use, Humans, Hypothalamus:metabolism, Male, Middle Aged, Nerve Tissue Proteins:metabolism, Neuroendocrine Secretory Pr.   

OBJECTIVES: We reported earlier that vasopressin (AVP) peptide expression is significantly decreased in the postmortem hypothalamus of glucocorticoid (GC) treated patients, while such a decrease was not observed in AVP prohormone (proAVP) expression. This indicated a GC-induced suppression of AVP synthesis at the posttranslational level. Here, we investigated in detail whether this decreased levels of AVP expression in GC treated patients might be due to the down regulation of the prohormone convertases PC-1 and PC-2, and the molecular chaperone 7B2, as was reported previously in some AVP-related disorders.

MATERIALS & METHODS: An immunocytochemical study was performed on post-mortem hypothalami of GC exposed patients and controls, in which quantification of proAVP, AVP, neurophysin (NP) and oxytocin (OXT) expression were done along with the quantification of PC1, PC2 and 7B2 expression in the paraventricular nucleus, by using a computerized image analysis system.

RESULTS: Expression of processed AVP in GC exposed patients was significantly decreased (p=0.021), while the amount of proAVP expression was unchanged. Despite the strong correlation between AVP and NP (the other cleavage product of proAVP) expression in the GC group (r=0.917, p=0.004), the mean NP immunoreactivity did not show a significant decrease in this group. Also the OXT expression was similar in both groups. Although in most of the GC treated patients, the expression intensities of PC1 and PC2 were decreased parallel to the decrease in AVP, the mean expression levels of neither of PC1 and PC2, nor of 7B2 were statistically different between the groups (p=0.20-0.80).

CONCLUSION: We conclude that the suppression of AVP expression by GCs is not mediated solely by the down regulation of PC1, PC2 or 7B2. Other mechanisms, which may contribute to the GC-induced posttranslational suppression of AVP, are discussed....

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Journal Article 2001; 22(6): 427-431 PubMed PMID: 11781539 Citation  Keywords:  Animals, Female, Gonadotropin-Releasing Hormone:metabolism, Hypothalamus:metabolism, Leptin:pharmacology, Luteinizing Hormone:blood, Pituitary Gland:metabolism, Rats, Sexual Maturation:drug effects,.   

OBJECTIVES: The aim of the present paper was to determine the sensitivity of the GnRH-LH axis to leptin administration during sexual maturation in female rats.

METHODS: For this purpose the hypothalamic concentration of GnRH, the pituitary content and the plasmatic levels of LH were determined in prepubertal (15 days of age) and peripubertal female rats (30 days of age), treated with leptin at a dose of 30 microg/kg. i.p. in a single injection, 90 min before sacrifice.

RESULTS: The results indicate that leptin significantly increased the GnRH concentration at 15 days of age (p <0.01). At 30 days of age the hormone did not significantly modify the hypothalamic GnRH content. Leptin increased the pituitary LH levels, both in prepubertal and peripubertal rats. Nevertheless, while the increase at 15 days of age was around 180%, in peripubertal rats it was about 51,2 %. In spite that leptin significantly increased LH plasmatic levels at both ages (p < 0.01 ), in rats of 15 days of age leptin increased LH in about 244%, at 30 days of age this increase was only about 102%.

CONCLUSION: These results clearly demonstrated that leptin has stimulatory effect on gonadotrophin axis been higher in prepubertal than in peripubertal rats. On these basis, and on the results of previous papers, (in which it has been demonstrated that the hypothalamic control of gonadotrophins by neurotransmitters and neuromodulators also showed qualitative and quantitative changes during sexual maturation), it is proposed that these differences are connected with the maturation of the neuroendocrine mechanisms involved in the regulatory action of leptin on the gonadotrophins axis....

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