Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sex difference”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed2005

Sex differences in the location of immunochemically defined cell populations in the mouse preoptic area/anterior hypothalamus.

The preoptic area/anterior hypothalamus (POA/AH) is sexually dimorphic in many vertebrates. We have defined specific cell populations within the POA/AH using immunocytochemical markers for estrogen receptor beta (ERbeta) and the R1 subunit of the GABA(B) receptor (GABA(B)R1). Our previous finding of sex differences in cell migration in this region in embryonic day 15 mice led us to examine sex differences in the location or size of chemically identified cell groups. At embryonic day 17 (E17), cells containing immunoreactive (ir) ERbeta in females were located more dorsal and lateral than those in males. In contrast to this positional sex difference seen at E17, ERbeta expression at P0 and adulthood showed a sex difference in cell number and area of immunoreactivity with a higher expression of ERbeta in males than females. Furthermore, in animals that were genetically deprived of gonadal and adrenal hormones by virtue of a disrupted gene coding for steroidogenic factor 1, cells containing ir ERbeta followed a female phenotype for location at E17 and a female phenotype for number of ir cells at P0 regardless of genetic sex, suggesting that circulating hormones may be influencing cell position in the POA/AH. A second phenotypically identified cell group containing ir GABA(B)R1 also had a sex difference in cell positions at E17. Females expressed GABA(B)R1 in cells with a more dorsal position than in males. These results provide support for the suggestion that sex differences in cellular organization in the developing hypothalamus arise from sex differences in cell migration.

Age Factors↗
PubMed1997

Scoring procedure, performance factors, and magnitude of sex differences in spatial performance.

The purpose of the present study was to demonstrate the influence of procedural factors on the magnitude of sex differences in a test of spatial ability. Two hundred and seven females and 155 males were administered the Mental Rotations Test (MRT) under timed and untimed conditions. Four different scoring procedures were used: total score, ratio of correct responses to the number of items attempted, score out of 24, and score out of 48. Significant sex differences were obtained in the timed condition but not in the untimed condition. Results also revealed that the magnitude of sex differences was reduced when a ratio score was used. Analysis of the pattern of responses provided insights into the causes of sex differences on the MRT. Results are interpreted in terms of their implications for research on sex differences in spatial ability.

Female↗
PubMed1992

Sex differences in gastric alcohol dehydrogenase activity in Sprague-Dawley rats.

The effects of sex differences and of fasting on gastric alcohol dehydrogenase activity were determined in Sprague-Dawley rats. Gastric alcohol dehydrogenase activity and enzyme protein levels were higher in female than in male rats. Ovariectomy and orchiectomy had no effect on alcohol dehydrogenase and did not alter the sex difference in enzyme activity. Fasting decreased the enzyme activity more in female than in male rats, abolishing the sex difference. Serum gastrin levels measured in female rats decreased on fasting and returned to normal levels within 24 hours of refeeding. Short- and long-term administration of pentagastrin to fasted and fed female rats did not affect the enzyme activity or enzyme protein level, except for a transient increase in enzyme activity but not in enzyme protein level 12 hours after administration to fasted fats. Omeprazole, which increased serum gastrin levels and decreased enzyme activity but not enzyme protein levels, was found to be a competitive inhibitor of the enzyme with a Ki of 0.40 mmol/L. The mechanisms for the sex differences and changes with fasting in rat gastric alcohol dehydrogenase activity remain unknown.

Alcohol Dehydrogenase↗
PubMed2003

Subgroup analysis of sex difference on the Vandenberg-Kuse mental rotation test.

A large sex difference has been elicited on the Vandenberg-Kuse mental rotation test. Prior research emphasizes the biological root of this sex difference. In recent experiments we confirmed this viewpoint. A large sample was administered the test, and the distributions of scores for men and women (N = 138; 68 men and 70 women: ages 19 to 23 years). The mean scores were used as cut-off points to group the men and the women in different subgroups (Low/Women, High/Women, Low/Men, High/Men). There were large differences among all subgroups, reinforcing Kimura's testosterone hypothesis for sex differences in spatial ability.

Adult↗
PubMed1982

Sex differences in life satisfaction among the elderly.

Sex differences in life satisfaction are a recurrent research issue in the field of social gerontology. However, the evidence concerning the effect of sex on morale is still inconclusive. This may be due to (a) the neglect of other relevant variables, (b) the failure to distinguish between main effects and interaction effects, and (c) the lack of formal statistical tests in making comparisons. In this study, a causal model of life satisfaction is proposed and evaluated by using four data sets with sample sizes ranging from 961 to 3,996. The proposed structural model fitted both the male and female subsamples reasonably well. The findings were also replicated across these four data sets. No systematic sex difference was found in terms of structural parameters. This indicates that the same causal mechanism is operating among the males as well as the females.

Aged↗
PubMed2004

Sex differences in the oxygen uptake kinetic response to heavy-intensity exercise in prepubertal children.

It has been demonstrated that there are no sex differences in the oxygen uptake (V(.)O(2)) kinetic response to moderate intensity exercise. However, sex differences in the response to maximal exercise are readily apparent even in the prepubertal years. The purpose of this study was therefore to investigate if sex differences exist in the V(.)O(2) kinetic response to heavy-intensity exercise. Forty-eight prepubertal children (25 male, 23 female) completed four transitions from baseline to 40% of the difference between their previously determined T(V-slope) (ventilatory threshold determined by the V-slope method) and peak V(.)O(2) on an electronically braked cycle ergometer. Each subject's breath-by-breath responses were interpolated to 1 s intervals, time aligned and averaged. The data following phase 1 were fit with: (1) a double exponential model and (2) a single exponential model within a fitting window that was previously identified to exclude the slow component. There were no significant differences in the parameters of the primary component between each model. Subsequent analysis was carried out using model 2. The primary time constant (tau(1)) was significantly (P<0.05) faster in boys [17.6 (5.8) s] than girls [21.9 (8.2) s], and the slow component contribution to the total change in amplitude after 9 min was significantly greater in girls [11.8 (5.5)%] than boys [8.9 (3.7)%]. Sex differences in the kinetic response to heavy-intensity exercise were identified and suggest that during the prepubertal years, sex differences exist in the ability to deliver and/or utilise oxygen in children.

Child↗
PubMed2003

Sex differences in (-)-pentazocine antinociception: comparison to morphine and spiradoline in four rat strains using a thermal nociceptive assay.

The present study examined the influence of sex on the antinociceptive effects of (-)-pentazocine, morphine and spiradoline in four rat strains, using a warm-water (50, 52 and 55 degrees C) tail-withdrawal procedure. In F344, Lewis, Sprague-Dawley (SD) and Wistar rats, baseline latencies decreased with increases in water temperature, and at each water temperature latencies were longer in males than in their female counterparts. Morphine and spiradoline produced maximal or near maximal antinociceptive effects in males and females of each strain. Whereas morphine was generally more potent in males, sex differences were not consistently observed with spiradoline. In contrast, there were marked sex differences with (-)-pentazocine, and in each strain (-)-pentazocine was more potent and produced a greater maximal effect in males. The magnitude of the sex differences varied markedly across strains, with (-)-pentazocine being 2.5-fold more potent in males of the F344 strain, but 11-fold more potent in males of the Wistar strain. When collapsed across nociceptive stimulus intensities, sex differences were largest in the Wistar and Lewis strains and smallest in the SD and F344 strains. The present findings indicate that there are marked sex differences in (-)-pentazocine antinociception, and that the magnitude of this effect is genotype dependent.

Analgesics↗
PubMed1990

Developmental sex differences in brain aromatase activity are related to androgen level.

Sex differences in the metabolism of testosterone (T) in the developing brain of quail were examined using an in vitro microassay. During each developmental stage (day before hatching, hatching and 2 days after hatching) aromatase activity was higher in hypothalamic areas than in a control neostriatal area. There was no sex difference in oestradiol-17 beta (E2) formation in the late embryonic brain or at hatching. But aromatase activity in the male preoptic-anterior hypothalamic area was 50% higher than in females by day 2. No regional differences in brain 5 beta-reductase activity were detected at any of the developmental stages sampled. There was a sex difference in production of catabolic 5 beta-reduced metabolites. Male 5 beta-reductase activity declined continuously from high embryonic levels in all areas, whereas female enzyme activity showed an increase at hatching. In contrast to plasma progesterone, levels of T were higher in the male than in the female by day 1 after hatching. We suggest that elevated circulating T in the male after hatching may account for the sexual dimorphism in brain aromatase activity.

Androgens↗
PubMed2005

Varying contributions of growth and ageing to racial and sex differences in femoral neck structure and strength in old age.

The structural basis of racial and sex differences in femoral neck (FN) fragility in old age was assessed in a cross-sectional study of 829 healthy Chinese and 1181 healthy Caucasian subjects aged 18 to 93 years in Melbourne, Australia. We measured FN bone mineral density (BMD), periosteal diameter, and estimated endocortical diameter, cortical thickness, volumetric BMD (vBMD), section modulus, and buckling ratio using dual X-ray absorptiometry. Racial and sex differences in structural and strength indices were adjusted for age, bone length and body weight and were expressed in standard deviation (SD) unit. In young adulthood, Chinese women had a 0.85 SD narrower FN, a 0.47 SD thinner cortex and a 0.79 SD shorter FN axis length (FNAL) than Caucasian women. Across age, Chinese and Caucasian women had similar increments in endocortical and periosteal diameters and similar decrements in cortical thickness and vBMD (both approximately 20%). In young adult males, FN periosteal diameter did not differ by race, but cortical thickness was 0.35 SD lower in Chinese than Caucasians. Across age, increments in periosteal and endocortical diameters were less in Chinese than Caucasian men so cortical thickness and vBMD diminished less in Chinese than in Caucasian men. In both races, young adult women had narrower FN than men. As Chinese women had a greater increment in periosteal diameter than Chinese men across age, the sex difference in FN periosteal diameter established in young adulthood diminished in old age. As Caucasian men had a greater increment in periosteal diameter than Caucasian women, the sex difference in FN periosteal diameter established in young adulthood increased with age. In old age, for both sexes, Chinese had a higher fracture risk in bending than Caucasians, but a lower fracture risk by buckling. For both races, women had a higher fracture risk in bending than men. Racial and sexual dimorphism in the absolute and relative behavior of the periosteal and endocortical surfaces throughout life produce race- and sex-specific differences in FN size, cortical thickness, and indices of bone strength in old age.

Absorptiometry, Photon↗
PubMed2005

Sex differences in the associations among psychological factors and pain report: a novel psychophysical study of patients with chronic low back pain.

UNLABELLED: Previous studies have consistently suggested that there are sex differences in pain report, but there is no consensus regarding sex differences in the associations among psychological factors and pain report. This cross-sectional study used a novel, clinically relevant, psychophysical pain-induction technique to examine sex differences between sensory and affective pain report and sex differences in the association of depression, pain related anxiety, and catastrophizing with pain report. Patients with chronic low back pain (N = 53) were recruited from an outpatient spine clinic, and those consenting completed self-report measures of pain-related anxiety, depression, pain catastrophizing, and pain. A measure of induced low back pain was obtained by having study participants perform a protocol on the MedXtrade mark Low-Back Exercise Apparatus. Our results indicated that no sex differences were detected in psychological factors and self-reported or induced low back pain. However, the relationships between pain related anxiety and self-report of low back pain (z = 2.51, P < .05) and between pain-related anxiety and induced low back pain (z = 3.00, P < .05) were significantly stronger in men than women. These findings suggest that anxiety was linked to self-reported and induced low back pain for men, but not for women. PERSPECTIVE: Results of this study suggest that pain-related anxiety has a stronger association with psychophysical and clinical reports of low back pain for men.

Adolescent↗
PubMed2002

No sex differences in contrast sensitivity and reaction time to spatial frequency.

This study investigated the possibility of sex differences in spatial frequency processing by measuring contrast sensitivity and reaction time to spatial frequency in the same 20 men and 20 women. This is the first study to investigate sex differences in reaction time to spatial frequency and the first to study sex differences in contrast sensitivity and reaction time within the same participants. No sex differences were found in either contrast sensitivity or reaction time measures, suggesting that women and men process spatial frequency information similarly.

Adolescent↗
PubMed2003

Sex differences in empathy and its relation to juvenile offending.

Implicit in most theoretical accounts of sex differences in offending is the assumption that females are less likely than males to engage in crime--especially serious, violent crime--in part because of their comparatively higher levels of concern for others and stronger affiliative ties. Much research suggests that significant sex differences in both empathy and serious offending emerge in adolescence, with females displaying notably higher levels of empathy and males engaging in notably higher levels of serious offending. However, there has been little empirical work assessing the degree to which sex differences in empathy among adolescents can account for sex differences in offending. This research uses data from a sample of adolescents attending public high schools in Philadelphia (n = 425) and a sample of adolescents incarcerated in the California Youth Authority (CYA) (n = 232) to examine the relation between empathy and serious offending. Results suggest that empathy acts as a protective factor for both males and females but that there are subtle differences among males and females in the relation between empathy and offending.

Adolescent↗
PubMed1988

Sex differences in osteoarthritis of the knee. The role of obesity.

This study investigated the role of obesity (body mass index, total body weight, triceps skinfold, subscapular skinfold) compared with other anthropometric variables (body fat distribution, muscularity, elbow breadth, bitrochanteric breadth) in order to explain previously noted sex differences in osteoarthritis of the knee. Anthropometric measures, self-reported symptoms, and knee x-ray data were analyzed for 3,905 adults aged 45-74 years with valid x-ray data from the First National Health and Nutrition Examination Survey, 1971-1975. Prevalence of knee osteoarthritis was 4.9% in women and 2.6% in men. The relative risk for women compared with men increased from 1.57 at 45-54 years to 2.14 at 65-74 years. Adjusting for body mass index and subscapular and triceps skinfolds reduced the sex difference, whereas adjusting for total body weight, body fat distribution, muscularity, and skeletal size increased the sex difference. Body mass index was the variable that best reduced the sex difference when the other variables were included in the analysis; it did not, however, eliminate the sex difference. No sex differences were found in the strength of the association between anthropometric variables and osteoarthritis, nor was there evidence to suggest that obesity is a consequence of knee osteoarthritis rather than a risk factor.

Adult↗
PubMed1978

Sex differences in psychoneuroendocrine reactions to examination stress.

Sex differences in adaptation and coping were studied by comparing neuroendocrine and psychological functions in male and female high-school students during 2--3 hr of routine school work (control condition) and a 6-hr matriculation examination (stress condition). In the control condition sex differences were slight and nonsignificant. During examination stress, the urinary excretion of cortisol, adrenaline, noradrenaline, and 3-methoxy-4-hydroxy-phenylethylene glycol (MOPEG or MHPG) increased in both sexes, but to a consistently greater extent in the male group, significantly so for adrenaline and MOPEG. Both sexes performed equally well in the examination, but self-reports showed that feelings of success and confidence were common among males, whereas feelings of discomfort and failure dominated in the female group. High discomfort correlated with poor performance in the males but with good performance in the females.

Achievement↗
PubMed1981

Sex differences in the aggressive behaviour of schoolchildren.

An observational study was carried out to investigate whether sex differences in aggression, found in pre-school children in free-play situations, would also be found at older ages in the classroom. Equal numbers of boys and girls, aged 6 and 11 years, were observed individually in their school classrooms for eight 5 min periods, carried out over several weeks. At 11 years of age, boys showed more physical aggression than girls, a finding which resulted from a few boys showing higher scores than the remaining boys and the girls; girls showed more verbal aggression. These sex differences were not found at 6 years of age. At both ages, there was a higher proportion of same-sex than opposite-sex encounters. These results are discussed in terms of the generality of sex differences in aggression, the possibility of a sex difference in the form of aggressive acts, and the sex of the recipient of aggression.

Age Factors↗
PubMed1986

Sex differences in appetitive learning of mice.

Learning abilities of male and female ddY mice were compared in two appetitive tasks (a lever-press task and an 8-arm radial maze task), and two avoidance tasks (a shuttle box task and a light-dark discrimination T-maze task). In the two types of appetitive learning, male mice were significantly superior to female mice. Sex differences were particularly apparent in the acquisition process. In contrast, there was no significant sex difference in learning of the two avoidance tasks. A sex difference in appetitive learning was not found in juvenile mice prior to sexual maturation, and the mice which had established a lever-press response as juveniles did not show any significant difference in the performance level when tested as adults. Thus, a sex difference appeared only in the acquisition stage of adult mice. These results suggest that there exists a sex difference in motivation level for hunting food but not for feeding, and that it causes a sex difference in appetitive learning.

Aging↗
PubMed1978

Sex differences in the kinetic constants of ethylmorphine demethylation and type I binding to hepatic microsomal cytochrome P-450 in mice. The influence of castration and testosterone.

1. In the CPB-SE mouse strain sex differences were observed in the Km and Vmax of ethylmorphine demethylation and in the deltaAmax of its type I binding to cytochrome P-450. In the CPB-V strain a small sex difference in the Vmax of the demethylation was found, whereas Ks and deltaAmax of type I binding differed considerably. 2. Testosterone pre-treatment of female CPB-SE mice abolished all sex differences, as did castration of males, except in Vmax, which was partially decreased. In the CPB-V strain testosterone pre-treatment of females abolished sex differences in type I binding, but had no effect on ethylmorphine demethylation. 3. Km values exceeded the corresponding Ks in all cases and sex differences in deltaAmax far exceeded those in Vmax. It is concluded that the Km is determined not only by the Ks of type I binding and the reduction rate of the type I complex between ethylmorphine and cytochrome P-450. The larger sex differences in deltaAmax as compared with Vmax may be attributable to type I binding of ethylmorphine to cytochrome P-450 subspecies not involved in its demethylation.

Animals↗
PubMed2001

Sex differences in musculoskeletal pain.

Epidemiologic, clinical, and experimental evidence points to sex differences in musculoskeletal pain. Adult women more often have musculoskeletal problems than do men. Discrepant findings regarding the presence of such differences during childhood and adolescence continue. Biologic and psychosocial factors might account for these differences. The authors review evidence showing that mechanically induced pressure is more likely to show sex differences than other noxious stimuli and to discriminate between individuals suffering from musculoskeletal pain and matched controls. The authors suggest that a state of increased pain sensitivity, with a peripheral or central origin, predisposes individuals to chronic muscle pain conditions, and that there are sex differences in the operation of these mechanisms; women are vulnerable to the development and maintenance of musculoskeletal pain conditions.

Humans↗