Age related changes of N-acetyl-beta-D-glucosaminidase and L-alanine aminopeptidase in mouse kidney, urine and plasma

Age and sex dependent differences of N-acetyl-beta-D-glucosaminidase (NAG) and L-alanine aminopeptidase (AAP) activities in kidney, urine and plasma of male and female mice were studied. The sex difference in NAG activity appeared between 27 and 38 days of age with the manifestation of significant differences in body weight and kidney growth. NAG activity in male kidneys was 3-fold that in females and its urinary level in mature males was over 10-fold higher. Androgenic regulation was found not only in the NAG contents in the kidneys and in the urinary excretion but also in the plasma NAG level, which showed higher in females. On the other hand, AAP activity in kidney, urine and plasma did not show much sex differences. Age related changes in AAP activity were not found except in the kidney and marked androgenic regulation was also not found in AAP. These results indicate that NAG and AAP, which are both urinary enzymes used as indicators of renal lesions, may be regulated differently.     

Reduction of beta-galactosidase in the ketotic Chinese hamster kidney.

Kidneys from normal, diabetic-nonketotic and ketotic Chinese hamsters were homogenized, fractionated and assayed for beta-glucosidase, and beta-galactosidase activities. The kidneys of the ketotic animals were enlarged but the protein content in each subcellular fraction was similar in all three groups of animals. beta-Glucosidase was found chiefly in the soluble fraction and no difference was observed in these animals. beta-Galactosidase was distributed in both cytoplasmic and particulate fractions; difference in the specific activity of beta-galactosidase between control and ketotic animals was found in nuclear, lysosomal-mitochondrial, microsomal and soluble fractions.     

Circadian rhythms in the activities of brain and liver aldehyde dehydrogenase isozymes in mice

Circadian variations in the activities of aldehyde dehydrogenase (ALDH) isozymes in the subcellular fractions of the brain and liver were investigated in male and female mice of C57BL/6J strain. The rhythms in high Km-ALDH activities of brain and liver mitochondrial fractions which existed in ordinary light-dark cycle were not observed in animals maintained in the continuous darkness for two weeks. The rhythms in high Km-ALDH activities of hepatic soluble and microsomal fractions existed in both ordinary cycle and total darkness but the rhythmic phases were different. In the low Km-ALDH activity of hepatic mitochondrial fraction, the circadian rhythm was similar in two lighting conditions. There was sex difference in the existence of the circadian rhythm. It seems that the ALDH activity of mice is influenced by light-dark cycle and sex hormones.     

Sex difference in neural tube defects in p53-null mice is caused by differences in the complement of X not Y genes

To shed light on the biological origins of sex differences in neural tube defects (NTDs), we examined Trp53-null C57BL/6 mouse embryos and neonates at 10.5 and 18.5 days post coitus (dpc) and at birth. We confirmed that female embryos show more NTDs than males. We also examined mice in which the testis-determining gene Sry is deleted from the Y chromosome but inserted onto an autosome as a transgene, producing XX and XY gonadal females and XX and XY gonadal males. At birth, Trp53 nullizygous mice were predominantly XY rather than XX, irrespective of gonadal type, showing that the sex difference in the lethal effect of Trp53 nullizygosity by postnatal day 1 is caused by differences in sex chromosome complement. At 10.5 dpc, the incidence of NTDs in Trp53-null progeny of XY* mice, among which the number of the X chromosomes varies independently of the presence or absence of a Y chromosome, was higher in mice with two copies of the X chromosome than in mice with a single copy. The presence of a Y chromosome had no protective effect, suggesting that sex differences in NTDs are caused by sex differences in the number of X chromosomes.     

Androgens regulate mitochondrial cytochrome c oxidase and lysosomal hydrolases in mouse skeletal muscle.

The gastrocnemius, a fast-twitch white muscle, and the soleus, a slow-twitch red muscle, were studied in A/J mice. The specific activities of the lysosomal hydrolases, beta-D-glucuronidase, hexosaminidase, beta-D-galactosidase and arylsulphatase, the inner-mitochondrial-membrane enzyme cytochrome c oxidase, and the outer-mitochondrial-membrane enzyme monoamine oxidase, were greater in the soleus than in the gastrocnemius. The specific activities of the lysosomal hydrolases and cytochrome c oxidase in the gastrocnemius and soleus were substantially higher in male mice than in female mice. Orchiectomy abolished this sex difference. Testosterone increased the activities of the lysosomal hydrolases and cytochrome c oxidase and coincidentally induced muscle hypertrophy and an accretion of protein and RNA, but total DNA remained constant. Monoamine oxidase was unaffected by sex, orchiectomy and testosterone. These findings indicate that endogenous androgens regulate the activity of enzymes associated with lysosomes and the inner mitochondrial membrane, as well as muscle fibre growth in mouse skeletal muscle.     

Deletion of the Bax gene disrupts sexual behavior and modestly impairs motor function in mice

Cell death is a nearly ubiquitous feature of the developing nervous system, and differential death in males and females contributes to several well studied sex differences in neuron number. Nonetheless, the functional importance of neuronal cell death has been subjected to few direct tests. Bax, a pro-apoptotic protein, is required for cell death in many neural regions. Deletion of the Bax gene in mice increases neuron number in several areas and eliminates sex differences in cell number in the brain and spinal cord. Here, sexual and motor behaviors were examined in Bax-/- mice and their wild-type siblings to test the functional consequences of preventing Bax-dependent cell death. Animals were gonadectomized in adulthood and provided with ovarian hormones or with testosterone for tests of feminine and masculine sexual behaviors, respectively. Wild-type mice exhibited a sex difference in feminine sexual behavior, with high lordosis scores in females and low scores in males. This sex difference was eliminated by Bax deletion, with very low receptivity exhibited by both male and female Bax-/- mice. Masculine sexual behavior was not sexually dimorphic among wild-type mice, but mounts and pelvic thrusts were nearly eliminated in Bax-/- mice of both sexes. Motor strength and performance at low speeds on a RotaRod apparatus did not differ by sex or Bax gene status. However, Bax-/- animals exhibited impairments on the RotaRod at higher speeds. Thus, developmental cell death may be required for masculine and feminine sexual behaviors and the fine tuning of motor coordination.     

胎次、性别对成年小鼠海马齿状回神经发生及学习记忆的影响

目的探讨胎次、性别是否对成年小鼠海马齿状回神经发生及学习记忆产生影响。方法运用Morris水迷宫系统检测第1～3胎成年小鼠的学习记忆能力,腹腔注射BrdU,标记神经干细胞,检测不同胎次、性别小鼠海马齿状回中的神经发生的差异。结果 （1）在同性别、不同胎次成年小鼠间,第2胎的学习记忆能力（LMA）均显著地高于第1、3胎的,其影响规律为LMA2〉LMA1〉LMA3,且P〈0.05;在同胎次、不同性别成年小鼠间,雌性小鼠的LMA均高于雄性小鼠的,但其差异无显著性（P〉0.05）。（2）在同性别、不同胎次成年小鼠间,第2胎海马DG新生神经细胞的数量（N）均高于第1、3胎的,其影响规律分别为NF2〉NF3〉NF1和NM2〉NM1〉NM3,但其差异无显著性（P〉0.05）;在同胎次、不同性别成年小鼠间,雌性小鼠的N均高于雄性小鼠的,但其差异无显著性（P〉0.05）。结论胎次、性别对实验动物神经发生及学习记忆等方面产生的影响是肯定的。因此,在使用实验动物时,应予以充分考虑,尽量使用胎次、性别相同的。     

Galactosyltransferase Defects in Reeler Mouse Brains

Galactosyltransferase activities were examined in the cerebellum, cerebral cortex, and brain stem of reeler and wild-type mice. Galactosyltransferase assays were optimal for all required substrates, linear with incubation time, and proportional to protein concentration. In brain areas affected by the reeler mutation (i.e., cerebral cortex and cerebellum), galactosylation of both endogenous and exogenous glycoprotein acceptors was greatly reduced in reeler relative to controls. On the other hand, glycosylation of endogenous glycolipids was low, and equal between reeler and wild-type. Galactosyltransferase activities were similar, though not identical, in reeler and wild-type brain stems, which are phenotypically normal in reeler mice. Glucosyltransferase, beta-galactosidase, beta-N-acetylglucosaminidase, acid phosphatase, and lactate dehydrogenase specific activities were all unaffected in reeler cerebella, while galactosyltransferase activity was 52% of control. Inhibition of either UDPgalactose hydrolysis or beta-galactosidase had no effect on galactosyltransferase activity. The spectrum or galactosyltransferase deficiencies in reeler suggests that this enzyme is associated with the development of young granule cells.     

In vitro drug metabolism in male and female athymic,nude mice

Drug metabolism was studied in hepatic microsomal and post microsomal supernatant fractions from male and female athymic nude mice (nu/nu) and heterozygous (+/nu) and homozygous (+/+) wild-type controls. In males, the following enzyme activities were higher in athymic mice than in the wild-type: NADPH cytochrome c reductase, ethylmorphine and aminopyrine N-demethylases, native UDP glucuronyltransferase, and glutathione (GSH) S-aryltransferase. No differences were observed between groups in UDPNAG-activated UDP-glucuronyltransferase, N-acetyltransferase, or aniline hydroxylase activities or in amounts of cytochrome P-450. In female athymic mice, only ethylmorphine and aminopyrine N-demethylase activities were significantly higher than in female wild-type controls (+/+). The female athymic mice had mixed function oxidase activities that were less than the male athymic mice. There were no sex or strain differences in response to treatment with phenobarbital or 3-methylcholanthrene.     

Sex differences in the effects of amiloride on formalin test nociception in mice

Amiloride is a nonspecific blocker of acid-sensing ion channels (ASICs) that have been recently implicated in the mediation of mechanical and chemical/inflammatory nociception. Preliminary data using a transgenic model are suggestive of sex differences in the role of ASICs. We report here that systemic administration of amiloride (10-70 mg/kg ip) produces a robust, dose-dependent blockade of late/tonic phase nociceptive behavior on the mouse formalin test (5%; 20 microl) in female but not male mice, completely abolishing the known sex difference in formalin test response. Adult gonadectomy produced a "switching" of sex differences in amiloride efficacy, with castrated males displaying an amiloride blockade and ovariectomized females rendered less sensitive to amiloride. Gonadectomized mice could be switched back to their intact status using chronic estrogen benzoate or testosterone propionate replacement via osmotic minipump (6 microg/day or 250 microg/day, respectively). It is unclear whether this striking sex difference is due to sex-specific involvement of ASICs in pain processing, but the present data represent one of the first demonstrations of pain-related sex differences with no obvious opioid involvement.     

Mandible shape analysis in Y-congenic strains of mice.

In order to test for the presence of genes influencing morphology on the Y-chromosome of mice, a canonical discriminant analysis of variation in mandible shape was conducted in 4 inbred strains of mice and 4 Y-chromosome congenic partners. Genetic background-dependent differences were observed, as well as a small sex variation in some strains, but it was impossible to detect any difference related to the between-strain exchange of the Y-chromosome.     

Sex-related difference in food-anticipatory activity of mice

The expression of food-anticipatory activity (FAA) is induced by restricted feeding (RF), and its entrainment requires food-entrainable oscillators, the neuroanatomical basis of which is currently unclear. Although RF impacts various hormones, sex-related differences in FAA are unclear. 'Here, we report significantly more food-anticipatory wheel-running activity in male than in female mice during RF. In parallel with the sex-related difference in FAA, male and female mice display different food intake and body weight in response to RF. Since gonadal hormones could be involved in the sex-specific difference in FAA, we compared sham and gonadectomized male and female wild-type mice. In gonadectomized mice, the sex difference in FAA was abolished, indicating a role for gonadal hormones in FAA. Further, plasma concentrations of the hormone ghrelin were higher in female than in male mice during ad libitum (AL) feeding, and RF induced a temporal advance in its peak in both sexes. RF also shifted the expression peak of the circadian gene mPer1 in the hippocampus and liver, although no sex difference was found in either the level or the cyclic phase of its expression. Per1^Brdm1 mutant mice were still sexually dimorphic for FAA, but diminished FAA was noted in both male and female Per2^Brdm1 mutant mice. In summary, our results imply that gonadal hormones contribute to the sex difference in FAA, possibly through modulating ghrelin activity.     

Postnatal development of trypsin-like esteroproteases in mouse submandibular gland

The development of trypsin-like esteroproteases in the submandibular gland of mice was studied, using a newly synthesized naphthyl ester (tosyl-L-lysine alpha-naphthyl ester) for the preparation of zymograms and for histochemical demonstration of the enzyme. Esteroprotease activities were first detected spectrophotometrically on day 15 after birth; then increased markedly after day 20. A sex difference in esteroprotease activity appeared on day 25. Zymograms prepared after isoelectric focusing in polyacrylamide slab gels showed that the glands of neonatal mice contained esteroproteases with a rather different composition from that of adult mice. The adult type isozymes appeared first on day 15, and their activities increased markedly after day 20. Histochemical studies revealed that the isozymes of neonatal mice were derived from mast cells. A few striated ducts were first stained on day 15, and the sex difference of the granular tubules became obvious on day 25. These results indicate that the development of trypsin-like esteroproteases faithfully reflects the differentiation of granular tubules in the mouse submandibular gland, except in the neonatal period.     

The effect of practolol and atenolol on the lysosomal enzyme activity of the ventricular myocardium of rats]

The influence of cardioselective beta-blockers, practolol and atenolol, on acid phosphatase, acid deoxyribonuclease, cathepsin D, beta-glucosidase and beta-galactosidase activities was studied in homogenates of intact rat ventricular myocardium. In the presence of drugs (1 x 10(-9)-1 x 10(-5) M) the activities of acid phosphatase, cathepsin D, beta-glucosidase and beta-galactosidase tended to diminish but the activity of acid deoxyribonuclease tended to increase. Some differences in the influence of drugs on the enzyme activities were removed by prolongation of preincubation of homogenates with drugs. It is supposed that the mechanism of influence of beta-blockers on lysosomes of the intact rat ventricular myocardium in conditions of this study includes the specific drug binding to beta-adrenergic receptors situated on lysosomes.     

Behavioral despair in mice after prenatal stress

Maternal stress during pregnancy produced behavioral alterations in both sexes with regard to sexual behavior, aggressive, maternal, lateralization and depression. In the present paper, sex differences for depression in mice was studied. No sex differences between female and male mice groups were observed either in swimming-induced immobility or in the open-field test (ambulation, rearing and boluses). Prenatal stress produced: 1) an increase of immobility time in female mice for swimming-induced immobility, but not in male mice; 2) an increase of ambulation in female mice for open-field test, but not in male mice; 3) there were no significant differences in rearing and boluses between stress and control groups either for female or male mice. Prenatal stress increases the risk of depression and locomotor activity in adult female mice.     

Genetics of insect hemolymph α-mannosidase in the silkworm,Bombyx mori

The genetics of hemolymph alpha-mannosidase was investigated in the silkworm, Bombyx mori. By selecting individuals showing either high or low enzyme activities, homozygotes were separated, with activities varying about five-fold. No differences in the activities of beta-galactosidase and beta-N-acetylglucosaminidase were observed. Thus, it seems that high- and low-enzyme silkworms (High and Low Lines) share the same genetic background except for the gene concerning the activity of alpha-mannosidase. The synthesis of the enzyme is controlled by an autosomal allele. Furthermore, expression of the gene varies from tissue to tissue, and there is no correlation between enzyme activity and growth rate. The difference in activity between High and Low lines is due to the amount of active enzyme, not to an endogeneous activator or inhibitor. There was no isozymic difference in alpha-mannosidase.     

Sex Differences in Mathematics and Reading Achievement Are Inversely Related: Within- and Across-Nation Assessment of 10 Years of PISA Data

We analyzed one decade of data collected by the Programme for International Student Assessment (PISA), including the mathematics and reading performance of nearly 1.5 million 15 year olds in 75 countries. Across nations, boys scored higher than girls in mathematics, but lower than girls in reading. The sex difference in reading was three times as large as in mathematics. There was considerable variation in the extent of the sex differences between nations. There are countries without a sex difference in mathematics performance, and in some countries girls scored higher than boys. Boys scored lower in reading in all nations in all four PISA assessments (2000, 2003, 2006, 2009). Contrary to several previous studies, we found no evidence that the sex differences were related to nations’ gender equality indicators. Further, paradoxically, sex differences in mathematics were consistently and strongly inversely correlated with sex differences in reading: Countries with a smaller sex difference in mathematics had a larger sex difference in reading and vice versa. We demonstrate that this was not merely a between-nation, but also a within-nation effect. This effect is related to relative changes in these sex differences across the performance continuum: We did not find a sex difference in mathematics among the lowest performing students, but this is where the sex difference in reading was largest. In contrast, the sex difference in mathematics was largest among the higher performing students, and this is where the sex difference in reading was smallest. The implication is that if policy makers decide that changes in these sex differences are desired, different approaches will be needed to achieve this for reading and mathematics. Interventions that focus on high-achieving girls in mathematics and on low achieving boys in reading are likely to yield the strongest educational benefits.     

Sex chromosome complement affects nociception in tests of acute and chronic exposure to morphine in mice

We tested the role of sex chromosome complement and gonadal hormones in sex differences in several different paradigms measuring nociception and opioid analgesia using "four core genotypes" C57BL/6J mice. The genotypes include XX and XY gonadal males, and XX and XY gonadal females. Adult mice were gonadectomized and tested 3-4 weeks later, so that differences between sexes (mice with testes vs. ovaries) were attributable mainly to organizational effects of gonadal hormones, whereas differences between XX and XY mice were attributable to their complement of sex chromosomes. In Experiment 1 (hotplate test of acute morphine analgesia), XX mice of both gonadal sexes had significantly shorter hotplate baseline latencies prior to morphine than XY mice. In Experiment 2 (test of development of tolerance to morphine), mice were injected twice daily with 10 mg/kg morphine or saline for 6 days. Saline or the competitive NMDA antagonist CPP (3-(2-carboxypiperazin-4yl) propyl-1-phosphonic acid) (10 mg/kg) was co-injected. On day 7, mice were tested for hotplate latencies before and after administration of a challenge dose of morphine (10 mg/kg). XX mice showed shorter hotplate latencies than XY mice at baseline, and the XX-XY difference was greater following morphine. In Experiment 3, mice were injected with morphine (10 mg/kg) or saline, 15 min before intraplantar injection of formalin (5%/25 microl). XX mice licked their hindpaw more than XY mice within 5 min of formalin injection. The results indicate that X- or Y-linked genes have direct effects, not mediated by gonadal secretions, on sex differences in two different types of acute nociception.     

Sex differences in brain developing in the presence or absence of gonads

Brain sexual differentiation results from the interaction of genetic and hormonal influences. This study used a unique agonadal mouse model to determine relative contributions of genetic and gonadal hormone influences in the differentiation of selected brain regions. SF-1 knockout (SF-1 KO) mice are born without gonads and adrenal glands and are not exposed to endogenous sex steroids during fetal/neonatal development. Consequently, male and female SF-1 KO mice are born with female external genitalia and if left on their own, die shortly after birth due to adrenal insufficiency. In this study, SF-1 KO mice were rescued by neonatal adrenal transplantation to examine their brain morphology in adult life. To determine potential brain loci that might mediate functional sex differences, we examined the area and distribution of immunoreactive calbindin and neuronal nitric oxide synthase in the preoptic area (POA) and ventromedial nucleus of the hypothalamus, two areas previously reported to be sexually dimorphic in the mammalian brain. A sex difference in the positioning of cells containing immunoreactive calbindin in a group within the POA was clearly gonad dependent based on the elimination of the sex difference in SF-1 KO mice. Several other differences in the area of ventromedial hypothalamus and in POA were maintained in male and female SF-1 KO mice, suggesting gonad-independent genetic influences on sexually dimorphic brain development.