首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
In this study, we characterized more thoroughly the social behavior of vasopressin 1b receptor null (V1bR-/-) mice. We confirmed that V1bR-/- males exhibit less social aggression than their wild-type (V1bR+/+) littermates. We tested social preference by giving male subjects a choice between pairs of soiled or clean bedding. In general, V1bR+/+ mice spent significantly more time engaged in chemoinvestigation of these social stimuli than V1bR-/- mice. Male V1bR+/+ mice preferred female-soiled bedding over male-soiled bedding, male-soiled bedding over clean bedding, and female-soiled bedding over clean bedding. In contrast, V1bR-/- males failed to exhibit a preference for any bedding. This difference in behavior is not explained by an anosmic condition as there were no differences between V1bR-/- and V1bR+/+ mice in their abilities to detect a cookie buried in clean bedding, or in their ability to perform in an operant conditioning task using a fully automated liquid dilution olfactometer. In the latter task, male V1bR-/- mice were fully capable of discriminating between male and female mouse urine. The latencies to learn this task did not differ between the two genotypes. Thus, a V1bR-/- male's ability to differentiate between male and female chemosensory cues appears no different than that of a V1bR+/+ male's. We propose that the V1bR plays an important role in social motivation, perhaps by coupling the processing, integration, and/or interpretation of chemosensory cues with the appropriate behavioral response.  相似文献   

2.
Male skeletal muscles are generally faster and have higher maximum power output than female muscles. Conversely, during repeated contractions, female muscles are generally more fatigue resistant and recover faster. We studied the role of estrogen receptor-beta (ERbeta) in this gender difference by comparing contractile function of soleus (mainly slow-twitch) and extensor digitorum longus (fast-twitch) muscles isolated from ERbeta-deficient (ERbeta(-/-)) and wild-type mice of both sexes. Results showed generally shorter contraction and relaxation times in male compared with female muscles, and ERbeta deficiency had no effect on this. Fatigue (induced by repeated tetanic contractions) and recovery of female muscles were not affected by ERbeta deficiency. However, male ERbeta(-/-) muscles were slightly more fatigue resistant and produced higher forces during the recovery period than wild-type male muscles. In fact, female muscles and male ERbeta(-/-) muscles displayed markedly better recovery than male wild-type muscles. Gene screening of male soleus muscles showed 25 genes that were differently expressed in ERbeta(-/-) and wild-type mice. Five of these genes were selected for further analysis: muscle ankyrin repeat protein-2, muscle LIM protein, calsequestrin, parvalbumin, and aquaporin-1. Expression of these genes showed a similar general pattern: increased expression in male and decreased expression in female ERbeta(-/-) muscles. In conclusion, ERbeta deficiency results in increased performance during fatigue and recovery of male muscles, whereas female muscles are not affected. Improved contractile performance of male ERbeta(-/-) mouse muscles was associated with increased expression of mRNAs encoding important muscle proteins.  相似文献   

3.
Neuropsychiatric disorders in which reduced social interest is a common symptom, such as autism, depression, and anxiety, are frequently associated with genetic mutations affecting γ‐aminobutyric acid (GABA)ergic transmission. Benzodiazepine treatment, acting via GABA type‐A receptors, improves social interaction in male mouse models with autism‐like features. The protein diazepam binding inhibitor (DBI) can act as an endogenous benzodiazepine, but a role for DBI in social behavior has not been described. Here, we investigated the role of DBI in the social interest and recognition behavior of mice. The responses of DBI wild‐type and knockout male and female mice to ovariectomized female wild‐type mice (a neutral social stimulus) were evaluated in a habituation/dishabituation task. Both male and female knockout mice exhibited reduced social interest, and DBI knockout mice lacked the sex difference in social interest levels observed in wild‐type mice, in which males showed higher social interest levels than females. The ability to discriminate between familiar and novel stimulus mice (social recognition) was not impaired in DBI‐deficient mice of either sex. DBI knockouts could learn a rotarod motor task, and could discriminate between social and nonsocial odors. Both sexes of DBI knockout mice showed increased repetitive grooming behavior, but not in a manner that would account for the decrease in social investigation time. Genetic loss of DBI did not alter seminal vesicle weight, indicating that the social interest phenotype of males lacking DBI is not due to reduced circulating testosterone. Together, these studies show a novel role of DBI in driving social interest and motivation.  相似文献   

4.
《Bone and mineral》1994,24(1):43-58
This study examined the effects of estrogen (17β-estradiol) and testosterone on the growth of long bones in male and female mice, with and without gonadectomy. Weight and nose-to-tail length were determined at 3 weeks of age at time of gonadectomy, 7 days later at the onset of hormone therapy, and throughout the treatment period. Gonadectomized mice exhibited an initial weight gain during the pretreatment period but length was unaffected. Hormone treatment altered weight gain in surgical and intact animals in a gender- and hormone-dependent manner. Estradiol enhanced weight gain in intact mice, but inhibited weight gain in ovariectomized mice. Lower doses of estradiol increased weight gain in orchiectomized mice at early time points. Testosterone increased weight in intact females and males, but not in gonadectomized mice. Estradiol increased nose-to-tail length in intact females at early time points, but inhibited length in ovariectomized females at later times, and it decreased length in intact males. Testosterone increased length in normal females and normal males. Serum Ca was unaffected by ovariectomy, but orchiectomy resulted in decreased levels. Estradiol reduced serum Ca in gonadectomized animals; serum Ca was increased by estradiol treatment in intact females. Changes in tibial bone weight, ash weight and mineral composition, and relative sizes of epiphyseal and metaphyseal bone were gender-, gonadectomy- and hormone-specific. Bone weight was greater in ovariectomized mice. Ash weight per bone was comparable, but there was an increase in Ca and P content with ovariectomy. Estradiol increased bone weight, ash content, and bone Ca and P in ovariectomized and intact females. Orchiectomy alone did not alter bone weight, ash content, or Ca and P, but orchiectomized mice were sensitive to estradiol; all parameters were increased in the orchiectomized animals treated with estradiol. Analysis of the ash content and Ca and P per mg bone, rather than per bone, demonstrated estradiol and testosterone alter net bone formation, but not the amount of mineral per unit bone. Ovariectomy increased hypertrophic cartilage. While estradiol did not alter tibial area in ovariectomized mice, it caused an increase in intact females. The total amount of growth plate cartilage in ovariectomized animals was decreased by estradiol to levels typical of intact animals due to a greater decrease in the hypertrophic cartilage in the ovariectomized mice, as well as a greater increase in metaphyseal bone area. Testosterone had no effect on these parameters in the females. Orchiectomy decreased the amount of growth plate cartilage, but increased the hypertrophic zone. Estradiol increased growth plate cartilage in intact male mice, but decreased it in orchiectomized mice. This difference was also seen in the hypertrophic zone. Total growth plate cartilage and hypertrophic cartilage were increased by testosterone in intact males, whereas metaphyseal and epiphyseal bone area were decreased. The results show for the first time that there is a gender-specific response in both male and female mice to both estradiol and testosterone, whether or not the animals have been gonadectomized. For many parameters, orchiectomized mice behave like females in response to both sex steroids, indicating that the male gonad is needed for mouse bone to exhibit the male phenotypic response to estradiol and testosterone.  相似文献   

5.
Persons who develop low back pain from prolonged standing exhibit increased muscle cocontraction, decreased movement and increased spine extension. However, it is unclear how these factors relate to pain development. The purpose of this study was to use hip abductor fatigue to manipulate muscle activity patterns and determine its effects on standing behaviours and pain development. Forty participants stood for two hours twice, once following a hip abductor fatigue exercise (fatigue), and once without exercise beforehand (control). Trunk and gluteal muscle activity were measured to determine cocontraction. Lumbo-pelvic angles and force plates were used to assess posture and movement strategies. Visual analog scales differentiated pain (PDs) and non-pain developers (NPDs). PDs reported less low back pain during the fatigue session, with females having earlier reductions of similar scale than males. The fatigue session reduced gluteal and trunk cocontraction and increased centre of pressure movement; male and female PDs had opposing spine posture compensations. Muscle fatigue prior to standing reduced cocontraction, increased movement during standing and reduced the low back pain developed by PDs; the timing of pain reductions depended on spine postures adopted during standing.  相似文献   

6.
Summary Muscle precursor replication in Swiss mice, in which muscle regeneration is exceptionally vigorous, was compared with previous data for regeneration in BALBc mice. The tibialis anterior muscles of 23 male and 15 female inbred Swiss SJL/J mice were crush injured, and tritiated thymidine injected into mice at various times after injury to label replicating muscle precursors. Lesion samples were taken 10 days after injury, processed for autoradiography, and grain counts of myotube nuclei analysed. Muscle regeneration was more vigorous in male compared with female Swiss mice, and in both was strikingly greater than that in BALBc mice in which there was extensive fibrous connective tissue throughout the lesions. Autoradiographic analysis showed that muscle precursor replication started at 24 hours in Swiss mice, 6 hours earlier than the onset at 30 hours in BALBc mice. Muscle precursor replication appeared to be more active 96 hours after injury in female Swiss compared with male BALBc and male Swiss mice respectively, although numbers of precursor cells replicating at other times were similar. It is not known whether the slight difference in onset of muscle precursor replication can alone account for the more complete muscle regeneration seen in Swiss mice. Similar studies were carried out in 11 male and 10 female F1 hybrid (SJL/J x BALBc) mice. Analysis of labelled myotube nuclei showed that muscle precursors did not synthesise DNA prior to 30 hours after injury, and regeneration resembled that of the parental BALBc strain.  相似文献   

7.
Modulating the paracrine effects of bone marrow mesenchymal stem cells (BMSCs) may be important for the treatment of ischemic myocardial tissue. In this regard, endogenous estrogen may enhance BMSC vascular endothelial growth factor (VEGF) production. However, little information exists regarding the effect of testosterone on stem cell function. We hypothesized that 1) endogenous or exogenous estrogen will enhance stem cell production of VEGF and 2) endogenous or exogenous testosterone will inhibit BMSC VEGF production. BMSCs were collected from adult male, female, castrated male, and ovariectomized female rats. One hundred thousand cells were incubated with testosterone (1, 10, or 100 nM) or estrogen (0.15, 1.5, or 15 nM) for 48 h. Cell supernatants were collected, and VEGF was measured by ELISA. BMSCs harvested from castrated males, normal females, and ovariectomized females produced more VEGF compared with normal males. Castration was associated with the highest level (1,018 +/- 98.26 pg/ml) of VEGF production by BMSCs, which was significantly more than that produced by BMSCs harvested from normal male and normal female animals. Exogenous testosterone significantly reduced VEGF production in BMSCs harvested from ovariectomized females in a dose-dependent manner. Exogenous estrogen did not alter BMSC VEGF production. These findings suggest that testosterone may work on BMSCs to decrease protective growth factor production and that effective removal of testosterone's deleterious effects via castration may prove to be beneficial in terms of protective factor production. By manipulating the mechanisms that BMSCs use to produce growth factors, we may be able to engineer stem cells to produce maximum growth factors during therapeutic use.  相似文献   

8.
Since parathyroid hormone (PTH) increased FGF2 mRNA and protein expression in osteoblasts, and serum FGF-2 was increased in osteoporotic patients treated with PTH, we assessed whether the anabolic effect of PTH was impaired in Fgf2-/- mice. Eight-week-old Fgf2+/+ and Fgf2-/- male mice were treated with rhPTH 1-34 (80mug/kg) for 4 weeks. Micro-CT and histomorphometry demonstrated that PTH significantly increased parameters of bone formation in femurs from Fgf2+/+ mice but the changes were smaller and not significant in Fgf2-/- mice. IGF-1 was significantly reduced in serum from PTH-treated Fgf2-/- mice. DEXA analysis of femurs from Fgf2+/+, Fgf2+/-, and Fgf2-/- mice treated with rhPTH (160mug/kg) for 10 days showed that PTH significantly increased femoral BMD in Fgf2+/+ by 18%; by only 3% in Fgf2+/- mice and reduced by 3% in Fgf2-/- mice. We conclude that endogenous Fgf2 is important for maximum bone anabolic effect of PTH in mice.  相似文献   

9.
Development of a C57BL/6-+/+ TCR transgenic mouse containing the rearranged TCR alpha- and beta-chain specific for the Db + HY male Ag results in production of a nearly monoclonal population of early thymocytes expressing the Db + HY reactive TCR. These thymocytes are autoreactive in H-2Db male mice and undergo clonal deletion and down-regulation of CD8. To study the effect of the lpr gene on development of autoreactive T cells, these transgenic mice were backcrossed with C57BL/6-lpr/lpr mice. T cell populations in the thymus and spleen were analyzed by three-color flow cytometry for expression of CD4, CD8, and TCR. The thymus of TCR transgenic H-2b/b lpr/lpr male mice had an increase in percent and absolute number of CD8dull thymocytes compared to TCR transgenic H-2b/b +/+ male mice. However, there was not a complete defect in clonal deletion, because clonal deletion and down-regulation of CD8 was apparent in both +/+ and lpr/lpr H-2Db HY+ male mice compared to H-2Db HY- female mice. The phenotype of splenic T cells was almost identical in TCR transgenic +/+ and lpr/lpr males with about 50% CD4-CD8- T cells and 50% CD8+ T cells. However, there was a dramatic increase in the SMLR proliferative response of splenic T cells from TCR transgenic lpr/lpr males compared to TCR transgenic +/+ males. To determine the specificity of this response, spleen cells from TCR transgenic lpr/lpr and +/+ mice were cultured with irradiated H-2b/b and H-2k/k male and female spleen cells. T cells from TCR transgenic C57BL/6-lpr/lpr male mice had an increased proliferative response to H-2b/b male spleen cells compared to T cells from TCR transgenic C57BL/6(-)+/+ male mice, but both lpr/lpr and +/+ mice had a minimal response to irradiated H-2b/b female or H-2k/k male or female stimulator cells. The splenic T cells from TCR transgenic lpr/lpr mice also had an increased specific cytotoxic activity against H-2b/b male target cells compared to TCR transgenic +/+ mice. These results demonstrate that there is a defect in negative selection of self-reactive T cells in the thymus of lpr/lpr mice and a defect in induction or maintenance of clonal anergy of self-reactive T cells in the periphery of lpr/lpr mice.  相似文献   

10.
Effects of the s.c. administration of various doses of estradiol propionate (E.P.; 25-500 micrograms/kg) on the activities of carbonic anhydrase (CA), Mg(2+)-dependent ATPase and Mg(2+)-dependent, HCO3(-)-stimulated ATPase (Mg(2+)-HCO3(-)-ATPase) in rat duodenal mucosa and kidney cortex, and on body weight, organ weight and serum concentrations of testosterone and estradiol-17 beta, were examined in adult male, female, testectomized and ovariectomized rats. In normal male rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the kidney were increased in a dose-dependent manner and reached 1.6- and 2-fold of controls, respectively, after consecutive administration (daily for 7 days) of 500 micrograms E.P. with no changes in either enzyme activities in duodenal mucosa. The positive correlations (P less than 0.01) were observed by linear regression analysis between serum concentration of estradiol-17 beta and kidney cytosol CA or kidney brush border Mg(2+)-HCO3(-)-ATPase activities. In normal female rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the duodenal mucosa, and brush border Mg(2+)-HCO3(-)-ATPase activity in the kidney were increased by E.P. administration (100 and 500 micrograms/kg, daily for 7 days), however, kidney cytosol CA activity did not change by any dosage. Behavior of a part of both enzymes to E.P. in testectomized rats was altered almost in the same way to that observed in normal female rats and vice versa in ovariectomized rats. Body weight was decreased, in general, by consecutive administration of E.P. in a dose-dependent manner, and kidney weight was increased by E.P. in both male and female rats.  相似文献   

11.
The aim of this study was to analyze the influence of position and pauses on muscle activity and fatigue during the task of ironing. Ten female participants performed the task of ironing in two different positions (standing and sitting) for 10?min each with a 1-min pause at the end of each task. Muscle activity and fatigue from the upper trapezium, anterior deltoid, and pectoralis major were analyzed using surface electromyography. The results showed that the positions had no significant influence on muscle activity; nevertheless, they had significant influence on muscular fatigue. In addition, the pauses were possibly beneficial in decreasing the muscle fatigue, but the results were not conclusive.  相似文献   

12.
Women are thought to form fear memory more robust than men do and testosterone is suspected to play a role in determining such a sex difference. Mouse cued fear freezing was used to study the sex-related susceptibility and the role of testosterone in fear memory in humans. A 75-dB tone was found to provoke weak freezing, while 0.15-mA and 0.20-mA footshock caused strong freezing responses. No sex differences were noticed in the tone- or footshock-induced (naïve fear) freezing. Following the conditionings, female mice exhibited greater tone (cued fear)-induced freezing than did male mice. Nonetheless, female mice demonstrated indistinctive cued fear freezing across the estrous phases and ovariectomy did not affect such freezing in female mice. Orchidectomy enhanced the cued fear freezing in male mice. Systemic testosterone administrations and an intra-lateral nucleus of amygdala (LA) testosterone infusion diminished the cued fear freezing in orchidectomized male mice, while pretreatment with flutamide (Flu) eradicated these effects. Long-term potentiation (LTP) magnitude in LA has been known to correlate with the strength of the cued fear conditioning. We found that LA LTP magnitude was indeed greater in female than male mice. Orchidectomy enhanced LTP magnitude in males' LA, while ovariectomy decreased LTP magnitude in females' LA. Testosterone decreased LTP magnitude in orchidectomized males' LA and estradiol enhanced LTP magnitude in ovariectomized females' LA. Finally, male mice had lower LA GluR1 expression than female mice and orchidectomy enhanced the GluR1 expression in male mice. These findings, taken together, suggest that testosterone plays a critical role in rendering the sex differences in the cued fear freezing and LA LTP. Testosterone is negatively associated with LA LTP and the cued fear memory in male mice. However, ovarian hormones and LA LTP are loosely associated with the cued fear memory in female mice.  相似文献   

13.
Intact male and female spontaneously hypertensive rats showed a progressive increase in blood pressure with growth; male attained systolic blood pressure levels of 244 +/- 6 mmHg, and females 205 +/- 3 mmHg at age 22 weeks. Orchidectomy at age 4 weeks significantly attenuated the systolic blood pressure elevation in the male (195 +/- 4 mmHg at age 22 weeks), but ovariectomy at age 4 weeks had no effect on the development of hypertension in the female. The pattern of development of hypertension in orchidectomized males was the same as that in intact and ovariectomized females. Administration of testosterone propionate to gonadectomized rats of both sexes conferred a male pattern of blood pressure development. These results indicate that the sexually dimorphic pattern of hypertension in the spontaneously hypertensive rat is androgen dependent, rather than estrogen dependent. Plasma norepinephrine levels did not differ between the sexes, nor were they altered by gonadectomy or testosterone replacement, suggesting that the higher blood pressures in the intact male and androgen treated male and female SHR are not dependent on increased sympathetic outflow in the established phase of hypertension. Stores of norepinephrine in the posterior hypothalamic region were significantly greater in intact male rats and testosterone treated rats of both sexes than in intact or ovariectomized females, and were higher in the pons of intact female rats than in all other groups. These alterations in central catecholamine stores were not correlated with blood pressure. Further study is needed to assess the functional significance of these androgen mediated alterations in posterior hypothalamic neurons as a determinant of the androgen mediated sexual dimorphism of blood pressure in the spontaneously hypertensive rat.  相似文献   

14.
Phosphatidylcholine (PC) is made in the liver by the CDP-choline pathway and via phosphatidylethanolamine N-methyltransferase (PEMT), which catalyzes the conversion of phosphatidylethanolamine to PC. Unexpectedly, hepatic apolipoprotein B-100 secretion is inhibited in male, but not female, Pemt-/- mice (Noga, A. A., Y. Zhao, and D. E. Vance. 2002. J. Biol. Chem. 277: 42358-42365; Noga, A. A., and D. E. Vance. 2003. J. Biol. Chem. 278: 21851-21859). To gain further insight into this process, we compared PC metabolism in male and female mice fed chow or a high-fat/high-cholesterol (HF/HC) diet. Immunoblot analyses demonstrated that twice as much PEMT2 was present in livers from female compared with male mice. In contrast, assays of CTP:phosphocholine cytidylyltransferase from livers of Pemt+/+ mice demonstrated more active cytidylyltransferase in male than in female mice. Secretion of PEMT-derived PC into lipoproteins was examined in vivo by injection of mice with [methyl-3H]methionine in the presence of Triton WR1339. The PEMT-derived PC shifts to smaller-sized particles in response to a HF/HC diet, but only in male mice. Secretion of PEMT-derived PC into bile was enhanced in mice fed a HF/HC diet. These results demonstrate that the synthesis and targeting of PC produced by the PEMT pathway in the livers of mice differs in a gender- and diet-specific manner.  相似文献   

15.
16.
Motoneurons in the spinal nucleus of the bulbocavernosus (SNB) innervate the perineal muscles, bulbocavernosus (BC), and levator ani (LA). Testosterone regulates the survival of SNB motoneurons and BC/LA muscles during perinatal life. Previous findings suggest that effects of testosterone on this system may be mediated by trophic factors-in particular, by a factor acting through the ciliary neurotrophic factor alpha-receptor (CNTFRalpha). To test the role of CNTFRalpha in the response of the developing SNB system to testosterone, CNTFRalpha +/+ and -/- mice were treated with testosterone propionate (TP) or oil during late embryonic development. BC/LA muscle size and SNB motoneuron number were evaluated on the day of birth. Large sex differences in BC and LA muscle size were present in newborn mice of both genotypes, but muscle volumes were reduced in CNTFRalpha -/- animals relative to same-sex, wild-type controls. Prenatal testosterone treatment completely eliminated the sex difference in BC/LA muscle size in wild-type animals, and eliminated the effect of the CNTFRalpha gene deletion on muscle size in males. However, the effect of TP treatment on BC and LA muscle sizes was blunted in CNTFRalpha -/- females. SNB motoneuron number was sexually dimorphic in oil-treated, wild-type mice. In contrast, there was no sex difference in SNB motoneuron number in oil-treated, CNTFRalpha knockout mice. Prenatal treatment with testosterone did not increase SNB motoneuron number in CNTFRalpha -/- mice, but also did not significantly increase SNB motoneuron number in newborn wild-type animals. These findings confirm the absence of a sex difference in SNB motoneuron number in CNTFRalpha -/- mice. Moreover, the CNTFRalpha gene deletion influences perineal muscle development and the response of the perineal muscles to testosterone. Prenatal TP treatment of CNTFRalpha -/- males overcomes the effects of the gene deletion on the BC and LA muscles without a concomitant effect on SNB motoneuron number.  相似文献   

17.
1. In Wistar strain rats, the serum concentration of C-reactive protein (CRP) was 3.6 +/- 0.8 micrograms/ml at the birth and no apparent change was observed during 15 days after delivery. 2. Thereafter it increased about 30 times rapidly until day 30 and then rather gradually reaching the adult level of 0.4-0.8 mg/ml. 3. Before delivery, there were two peaks in the CRP level, on day 0 and day 15 of gestation. The concentrations were 0.70 +/- 0.06 and 0.77 +/- 0.10 mg/ml, respectively. 4. The CRP level decreased to 0.42 +/- 0.05 mg/ml at the delivery and increased to 0.54 +/- 0.05 mg/ml within 2 days after delivery. 5. The treatment with estradiol-17 beta resulted in the decrease of CRP (52%) in both ovariectomized and non-treated female rats. 6. The treatment with testosterone resulted in the increase of CRP in male but not in female rats. 7. However, in ovariectomized rats, testosterone elevated the serum CRP. 8. In neither ovariectomized nor intact female rats, progesterone and corticosterone showed any remarkable effect.  相似文献   

18.
Multiple injections of low-dose streptozotocin (LDSZ) induce immune-mediated insulitis and diabetes in C57BL/6 (H-2b) mice. To evaluate the role of the intercellular adhesion molecule-1 (ICAM-1) for LDSZ induced immune-mediated diabetes, we have investigated mice genetically deficient in the ICAM-1 gene (ICAM-1-/-) in comparison to wild-type (ICAM-1+/+) mice. ICAM-1-/- mice, which had a mixed genetic background of C57BL/6 and DBA/2 mice, were backcrossed to C57BL/6 mice and screened for H2b homogenicity. Mice received five daily injections of 40 mg/kg streptozotocin. On day 21 after the first LDSZ injection 55% of the ICAM-1+/+ (female 33%, male 80%) and 50% of the ICAM-1-/- (female 20%, male 100%), mice had blood glucose levels over 200 mg/dl. Mean blood glucose levels increased in response to LDSZ treatment, however, no differences between ICAM-1+/+ and ICAM-1-/- mice were noted. Histological examinations of pancreatic islets revealed mononuclear infiltration of pancreatic islets without significant differences between both groups of mice. In summary, LDSZ-induced immune-mediated insulitis and diabetes development occurs in ICAM-1-/- mice similarly than in ICAM-1+/+ mice. These results do not support the hypothesis that ICAM-1 plays a key role during immune-mediated infiltration and destruction of pancreatic islets in LDSZ induced diabetes.  相似文献   

19.
During fetal life female mice (Mus musculus) that develop between two male fetuses (2M females) have higher blood concentrations of testosterone than do females that do not develop next to a male fetus (0M females). In the first experiment reported here, sexual receptivity and sexual attractiveness to males were examined in young (5 month old) and old (17 month old) ovariectomized, estrogen- and progesterone-treated 0M and 2M female mice that were placed in like-age pairs with a male. Most males inseminated the 0M female prior to inseminating the 2M female regardless of age. In addition, 0M females were more likely to exhibit lordosis when mounted than were 2M females. When the same young females were 9 months of age and the old females were 21 months of age, they were treated with testosterone and again placed together in pairs along with a sexually receptive female. Young 2M females exhibited more aggression toward the testosterone-treated female partner, and also exhibited more mounting of the receptive female, than did young 0M females. But, both old 0M and old 2M females were highly aggressive and exhibited mounting. An increase in sensitivity to the effects of testosterone on behavior thus occurs during aging in 0M females, which are relatively insensitive to testosterone in young adulthood. In contrast, when treated with estrogen and progesterone, 0M females were more attractive to males and were more sexually receptive than 2M females regardless of age.  相似文献   

20.
T Matsuda  Y Nakano  T Kanda  H Iwata  A Baba 《Life sciences》1991,48(17):1627-1632
Subcutaneous injection of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) in mice caused hypothermia which was antagonized by pindolol. The hypothermic effect of 8-OH-DPAT was pronounced in female than in male mice. The sex difference in the hypothermic effect was also observed after pretreatment with proadifen. The hypothermic effect of 8-OH-DPAT was attenuated by ovariectomy. In the ovariectomized mice, the effect of 8-OH-DPAT on rectal temperature was enhanced by chronic estradiol and the enhancement was blocked by simultaneous administration of testosterone. In male mice the hypothermic effect of 8-OH-DPAT was enhanced by castration. These results suggest that gonadal hormones affect the 5-HT1A receptor-mediated response.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号