Adult Female Brain Research Articles

Male pheromone–stimulated neurogenesis in the adult female brain: possible role in mating behavior.

The regulation of female reproductive behaviors may involve memories of male pheromone signatures, formed in part by neural circuitry involving the olfactory bulb and hippocampus. These neural structures are the principal sites of adult neurogenesis; however, previous studies point to their independent regulation by sensory and physiological stimuli. Here we report that the pheromones of dominant (but not subordinate) males stimulate neuronal production in both the olfactory bulb and hippocampus of female mice, which are independently mediated by prolactin and luteinizing hormone, respectively. Neurogenesis induced by dominant-male pheromones correlates with a female preference for dominant males over subordinate males, whereas blocking neurogenesis with the mitotic inhibitor cytosine arabinoside eliminated this preference. These results suggest that male pheromones are involved in regulating neurogenesis in both the olfactory bulb and hippocampus, which may be important for female reproductive success.

Met-enkephalin modulates resistance to oxidative stress in mouse brain.

The purpose of this study was to investigate the effect of opioide peptide Met-enkephalin (MENK) on resistance to oxidative stress in the brain of 4, 10 and 18 months old CBA mice of both sexes. This was done by determination of oxidant status via lipid peroxidation (LPO) and antioxidant status by determination of total superoxide dismutase (tSOD), catalase (CAT) and glutathione peroxidase (Gpx). Results showed that brain of adult male mice is less resistant to oxidative stress than brain of adult females. The difference is mainly due to higher CAT activity and lower LPO activity in female brain. MENK decreased resistance to stress in the brain of both sexes but the effect appeared earlier in males (10 months of age) than in females (18 months of age). Also, MENK could pronounce its effect on resistance to oxidative stress in a gender-related manner: in female mice via regulation of antioxidant enzyme activities and in male mice via regulation of oxidant processes respectively.

Absorbed dose to the adult male and female brain from 18F-fluorodeoxyglucose.

The absorbed doses to adult male and female brains from 18F-fluorodeoxyglucose were investigated. A total of eight male and six female patients undergoing clinical positron tomography brain scans were included in this study. This patient population allowed for a comparison of the absorbed dose to the brain in men and women. For each patient, time-activity curves for the brain were generated, yielding cumulated activity measurements for the entire organ. From these cumulated activities the average residence times for both male and female subjects were calculated and then multiplied by the S-values from the MIRDOSE 3.1 software program for absorbed dose estimates. The average absorbed dose per administered activity to the adult male brain was found to be 4.2 x 10(-2) mGy MBq(-1), which is lower than that found for the adult female brain of 5.3 x 10(-2) mGy MBq(-1). Six of the male and all six female subjects were each studied on two separate occasions, allowing for an analysis of within-subject variability. The average variation in the self-dose for all 12 patients was found to be within 14%, suggesting that in most cases this method of obtaining a single dose estimate is precise.

Juvenile hormone biosynthesis in larval and adult stick insects, Carausius morosus

Corpora allata (CA) from adult egg-carrying Indian stick insects, Carausius morosus, synthesise and release juvenile hormone (JH) III in vitro. No JH biosynthesis was observed in larvae, young adults, and old adult females that do not carry sclerotised eggs. In females, which bear sclerotised eggs, a consistent JH biosynthesis was observed. Supplementation of precursors of JH biosynthesis (farnesol, mevalonic acid lactone) greatly enhanced JH biosynthesis in a stage-, age-, and dose-dependent manner, but CA from the last larval instar retained the biosynthesised JH within the gland. Elevated calcium concentration in the incubation medium stimulated JH biosynthesis by CA from older adults but had either no or a poor effect on CA from young adults and larvae. The results obtained with farnesol, mevalonic acid lactone, and calcium indicate that the rate-limiting steps of JH biosynthesis very likely occur before the formation of mevalonic acid and that these early steps cannot be stimulated by elevated calcium concentrations in larvae and young adults. In older adults, in which spontaneous JH biosynthesis occurs, elevated calcium concentration can markedly stimulate JH biosynthesis. A pre-purified extract from brains of adult females had a stimulating effect on JH biosynthesis by CA from adult females. The results indicate that JH biosynthesis in C. morosus may require food-derived farnesol and may be regulated by allatotropic signals from the brain, possibly triggered by sclerotised oocytes in the ovary.

Silver Concentrations in Human Tissues. Their Dependence on Dental Amalgam and Other Factors

Human tissue samples (liver, kidney cortex, 5 brain regions: grey matter of cerebrum, white matter of cerebrum, nucleus lentiformis, cerebellum, brain stem) from 173 decreased persons were analysed for silver (Ag) by GF-AAS (Graphite Furnace Atomic Absorption Spectrometry) and the results compared with the number of teeth with amalgam fillings and the concentration of inorganic mercury (Hg), which had been determined in the same tissue samples in a previous study. It was found that the mean Ag concentrations in liver and brain of adult females are approximately twice that of males. Moreover, the Ag concentrations, especially in the brain, depend possibly on age. To exclude these confounding factors as far as possible, the influence of dental amalgam and the correlation of Ag and Hg were evaluated only in a sub-group of 93 males, aged 11-50 years. In this sub-group statistically significant correlations were found between the number of teeth with dental amalgam and the Ag concentrations in the cerebral cortex and the liver. No such correlation was found for the kidney. Ag and inorg. Hg correlate well in this sub-group in the liver, but not in the cerebral cortex or the kidney. Individuals from this sub-group with (i) 0-2 and with (ii) more than 9 teeth with amalgam fillings show mean Ag concentrations (micrograms/kg in tissue wet weight, geom. mean) of 1.59 and 5.41 in the grey matter of cerebrum, 1.42 and 4.25 in the white matter of cerebrum, 1.53 and 4.89 in the nucleus lentiformis, 1.95 and 5.02 in the cerebellum, 1.05 and 3.27 in the brain stem, 3.40 and 8.15 in the liver and 0.42 and 0.44 in the kidney cortex. In contrast, comparing all individuals under investigation with only 0-2 teeth with amalgam no correlation between Ag and inorg. Hg could be found in liver, kidney cortex or cerebral cortex. These results show that amalgam fillings release Ag as well. Considering the different toxicokinetics of Ag and Hg it can be concluded that Ag is a reliable marker for the fact that the elevated concentrations of inorg. Hg found in tissues of individuals with amalgam fillings derive mainly from these fillings and not from other theoretically possible sources.

The Role of Estrogens in Schizophrenia Gender Differences

The male/female differences that have been described in schizophrenia are important because they may ultimately shed light on factors that mediate the expression of schizophrenic illness. The hypothesis of this article is that estrogens, either directly or indirectly, modify symptom expression and account for many of the observed gender differences. The role of sex hormones is divided into organizational and activational effects. Organizational effects take place during a critical period in fetal life and put a permanent stamp on the developing brain. Activational effects are the direct influences of circulating hormones that appear when hormonal levels rise, and wane when hormonal levels drop. Because levels of sex hormones in adult women fluctuate during the menstrual cycle, cyclic effects of high and low female hormones may induce specific responses by the adult female brain. All these effects have implications for genetic, environmental, pharmacological, neurocognitive, clinical, and epidemiological research in schizophrenia.

Neuropathological findings in 31 unselected Papua-New Guinea brains

The mean adult male brain weight was 1275g, with a range from 1075g to 1550g. The mean adult female brain weight was 1165g, with a range from 1010g to 1330g. On external macroscopic examination, 16 brains showed brachycephalic appearance and 7 brains showed prominent parietooccipital fissure. On microscopic examination, 8 brains showed media calcification in the arteries of globus pallidus, mild to moderate atherosclerotic changes and hyaline wall thickening was present in the subcortical and the basal ganglia arteries in 8 brains. Granular ependymitis was present in one case. Fragments of a sheathed filaria were seen in the brain of a 26-yr-old male. In 6 cases, a peculiar calcification surrounded the ventral surface of the medulla oblongata. The mean adult male brain weight was 1275g, with a range from 1075g to 1550g. The mean adult female brain weight was 1165g, with a range from 1010g to 1330g. On external macroscopic examination, 16 brains showed brachycephalic appearance and 7 brains showed prominent parietooccipital fissure. On microscopic examination, 8 brains showed media calcification in the arteries of globus pallidus, mild to moderate atherosclerotic changes and hyaline wall thickening was present in the subcortical and the basal ganglia arteries in 8 brains. Granular ependymitis was present in one case. Fragments of a sheathed filaria were seen in the brain of a 26-yr-old male. In 6 cases, a peculiar calcification surrounded the ventral surface of the medulla oblongata.

Properties and partial purification of an oestrogen receptor from neonatal rat brain

Hydrodynamic properties and partial purification of an estrogen receptor from neonatal rat brain are described. The high affinity estradiol binding protein of the neonatal brain behaves very similarly to the estradiol receptor of the adult female brain on sucrose density gradients. They both sediment at 8S on low salt gradients and at 4.5S on gradients containing .4 M potassium chloride. They are both completely suppressible by diethylstilbestrol and are both precipitated by 25% ammonium sulphate to give an 8S peak and aggregates on low salt gradients but a single 4.5S peak on gradients containing .4 M potassium chloride. On purification with ammonium sulphate the affinities of the neonatal receptor for estrone and 17beta-estradiol approach those of the adult. The residual differences in affinity are probably due to traces of estrogen binding protein (EBP) still remaining in the partially purified material. Dissociation of the steroid from EBP as occurs during LH20 chromatography during the dialysis of the ammonium sulphate precipitate may account for the lack of evidence of residual EBP on the sucrose gradients. It is concluded that the cytoplasmic estrogen receptors of neonatal and adult brain gradients. It is concluded that the cytoplasmic estrogen receptors of neonatal and adult brain although performing different functions are probably identical.