Number of dopamine neurons predicts prolactin levels in two inbred mouse strains

Mice of the BALB/cJ strain have more dopamine neurons than mice of the CBA/J strain. We now report that BALB/cJ mice have less circulating and pituitary prolactin than CBA/J mice, a relationship expected from the difference in tuberoinfundibular dopamine neuron number.     

Regional and strain variation in brain 3′∶5′ cyclic adenosine monophosphate of inbred mice

Summary Regional variations were found in cAMP levels in flash frozen mouse brains with the pons and cerebellum having higher levels than the cerebrum. There were also strain variations with CBA/J and BALB/cJ having higher levels than C57B1/6J in the pons and cerebellum.     

Regional and strain variation in brain 3':5' cyclic adenosine monophosphate of inbred mice.

Regional variations were found in cAMP levels in flash frozen mouse brains with the pons and cerebellum having higher levels than the cerebrum. There were also strain variations with CBA/J and BALB/cJ having higher levels than C57B1/6J in the pons and cerebellum.     

Effect of glucocorticoids injected into pregnant female mice and rats on weight of male sexual glands in adult offspring and testosterone level in fetus in genotype-dependent

Injection of corticosterone into CBA/Lac, C57BL/6J and BALB/c mice, or hydrocortisone into aggressive and domesticated rats, on days 16 and 18 of pregnancy decreased the weight of sexual glands in adult male offspring of the C57BL/6J and domesticated mothers but increased these values in male offspring of the CBA/Lac and aggressive mothers. When injected into pregnant aggressive and domesticated rats, corticosterone affected testosterone levels in 21-day-old male fetuses. The changes were also genotype-dependent and followed the course of changes in the weight of the accessory sex glands in adults. It is suggested that glucocorticoids given during the prenatal period can effect plasma testosterone levels of male fetuses and the development of the sexual glands in a genotype-dependent manner.     

Genetic differences between inbred strains of mice; a new source of variation in high-sulphur keratins

Summary Proteins were extracted by improved techniques from the hair of inbred strains of Peru, C57BL/6 and CBA/Ca mice. The extracts were characterized by amino acid analysis and high resolution polyacrylamide gel electrophoresis, and previously unreported strain differences were observed. Genetic analysis confirmed them.We are grateful to Dr Speakman, Dr J. Findlay and Prof. J. Shire for helpful discussion, the Joint Sequencing Unit (Dept of Biochemistry/Genetics) for carrying out the amino acid analyses, and the mouse house staff. We also thank the S.R.C. for the grant GR/B/62877 which supported this work.     

Genotype-specific reduction in methyl nitrosourea (MNU) induced sister chromatid exchanges (SCE) in vivo during aging

We studied mice from five strains (BALB/c, C3H/HeSnJ, C57BL/6J, Csb and 129/ReJ) at two ages (young, 10 +/- 1 weeks; and old, 67 +/- 3 weeks) for the induction of sister chromatid exchanges (SCEs) in vivo by methyl nitrosourea (MNU). The SCE frequency is genotype-specific. The F1 phenotype resembles the 'low' responding parent. SCE induction is significantly lower in the older animals of each strain than their younger counterparts, and the reduction of SCE/cell with old age is strain-specific. A general explanation for these results must include strain differences in relative mutagenic sensitivity, genotype-specific pattern of reduction in DNA repair and other such factors affecting SCE formation, with old age.     

Tumor incidence in Visna virus inoculated mice.

Mice (female Swiss albino) inoculated when newborn with Visna virus had tumors in 77% of cases when examined 8-12 months later. The tumors were mainly of the mammary carcinoma type. The tumor incidence in non-infected control animals was only 20%. In contrast, no increased incidence of tumors was observed among Visna virus-inoculated inbred mice (BALB/c, CBA and DBA) with low incidence of spontaneous mammary carcinoma.     

Changes in brain dopamine levels and aggressive behavior with aging in 2 mouse strains

Summary The genetic programming of brain monoamine changes with aging show remarkable differences in 2 mouse strains. A marked increase in dopamine occurred in 32-week-old grouped ICR mice and the males showed intense irritability and aggressive behavior. Brain amines changed only slightly in old C57BL6J mice and behavior remained benign. Old females showed similar amine changes but aggressive behavior did not occur in either strain.     

Changes in brain dopamine levels and aggressive behavior with aging in 2 mouse strains

The genetic programming of brain monoamine changes with aging show remarkable differences in 2 mouse strains. A marked increase in dopamine occurred in 32-week-old grouped ICR mice and the males showed intense irritability and aggressive behavior. Brain amines changed only slightly in old C57BL6J mice and behavior remained benign. Old females showed similar amine changes but aggresive behavior did not occur in either strain.     

Genetic differences between inbred strains of mice; a new source of variation in high-sulphur keratins

Proteins were extracted by improved techniques from the hair of inbred strains of Peru, C57BL/6 and CBA/Ca mice. The extracts were characterized by amino acid analysis and high resolution polyacrylamide gel electrophoresis, and previously unreported strain differences were observed. Genetic analysis confirmed them.     

Tumor incidence in Visna virus inoculated mice

Summary Mice (female Swiss albino) inoculated when newborn with Visna virus had tumors in 77% of cases when examined 8–12 months later. The tumors were mainly of the mammary carcinoma type. The tumor incidence in noninfected control animals was only 20%. In contrast, no increased incidence of tumors was observed among Visna virus-inoculated inbred mice (BALB/c, CBA and DBA) with low incidence of spontaneous mammary carcinoma.This study was supported by grant No. B75-16X-4511-01 of the Swedish Medical Research Council.     

Effects of d-amphetamine upon open field behaviour in two inbred strains of mice

Résumé Chez des souris C57BL/10J, on constate une augmentation de l'activité locomotrice durant tous les 7 jours qui suivent leur injection avec la d-amphétamine. Chez des souris BALB/cJ, cette augmentation n'apparaît pas, sauf légèrement après le quatrième jour. Des facteurs génétiques jouent un rôle important dans la détermination de la réponse comportementale à la d-amphétamine.

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This research was funded by National Institutes of Mental Health grant No. MH-18517-01. Facilities were provided by the Maryland Psychiatric Research Center, Baltimore, Maryland.     

Genotype-specific reduction in methyl nitrosourea (MNU) induced sister chromatid exchanges (SCE) in vivo during aging

Summary We studied mice from five strains (BALB/c, C3H/HeSnJ, C57BL/6J, Cs^b and 129/ReJ) at two ages (young, 10±1 weeks; and old, 67±3 weeks) for the induction of sister chromatid exchanges (SCEs) in vivo by methyl nitrosourea (MNU). The SCE frequency is genotype-specific. The F₁ phenotype resembles the low responding parent. SCE induction is significantly lower in the older animals of each strain than their younger counterparts, and the reduction of SCE/cell with old age is strain-specific. A general explanation for these results must include strain differences in relative mutagenic sensitivity, genotype-specific pattern of reduction in DNA repair and other such factors affecting SCE formation, with old age.     

Strain differences in the lethal factor exerted by submandibular glands transplanted from male mice

Zusammenfassung Der Lethalfaktor von Submandibulardrüsen-Transplantaten wurde bei Mäusen verschiedener Mutanten, C3H, CBA, BALB/c und C57BL, beobachtet. Die Intensität des Lethalfaktors war am stärksten in Transplantaten von BALB/c Mäusen und am geringsten in denen von C3H Mäusen. Die C57BL-Variante war am anfälligsten für den Lethalfaktor.     

Adenosine deaminase activity in peripheral blood cells from SJL/J mice

Summary Adenosine deaminase (ADA) activities were measured in peripheral blood cells of SJL/J mice, and compared with those of C57BL/6J animals. No association was observed between the levels of lymphocyte or erythrocyte ADA and immunologic abnormalities in SJL/J mice nor was evidence obtained to suggest a relationship between ADA activity and tumorigenesis in this strain.This work was supported in part by a University College Faculty Research Grant.     

«Colony-stimulating activity» im Serum und der Milz nach Rauscher Virusinfektion

Summary Colony-stimulating activity (CSA) of serum and spleen was studied in CBA/J mice 1–5 days after Rauscher virus infection, using the agar culture system with normal mouse bone marrow cells as target cells. A sharp increase of CSA was observed with a peak after 2 days in both sites; after 5 days control levels are reached.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft (SFB 112, Zellsystemphysiologie).     

Bacterial lipopolysaccharide (LPS) enhances concanavalin A reactivity of thymocytes from the low-LPS-responder mouse strain C3H/Hej.

The capacity of LPS to enhance Con A reactivity of thymocytes was studied comparatively in the low-LPS-responder C3H/Hej mice and the high-LPS-responder CBA mice. The extent of synergism LPS + Con A was found similar in both strains.     

Genetic and developmental defects of the mouse corpus callosum

Among adult BALB mice fewer than 20% usually have a small or absent corpus callosum (CC) and inheritance is polygenic. In the fetus at the time when the CC normally forms, however, almost all BALB mice show a distinct bulge in the interhemispheric fissure and grossly retarded commissure formation, and inheritance appears to result from two autosomal loci, provided the overall maturity of fetuses is equated. Most fetuses recover from the early defect when the CC axons manage to cross over the hippocampal commissure, and thus there is developmental compensation for a genetic defect rather than arrested midline development. The pattern of interhemispheric connections when the adult CC is very small is topographically normal in most respects, despite the unusual paths of the axons. The proportion of mice which fail to recover completely can be doubled by certain features of the maternal environment, and the severity of defects in adults can also be exacerbated by new genetic mutations which create new BALB substrains. The behavioral consequences of absent CC in mice are not known, nor have electrophysiological patterns been examined. The mouse provides an important model for prenatal ontogeny and cortical organization in human CC agenesis, because these data are not readily available for the human condition.     

The origin of hemopoietic cells in ectopic implants of spleen and marrow

Summary Spleen and marrow tissues were cross-transplanted between CBA and CBA/HT6 mice. The majority of karyotypes in the regenerated implants were of recipient origin indicating that these implants are chimeric structures with the stroma of donor origin providing a framework for the proliferation of the recipient's hemopoietic stem cell.Supported by NIH Grant AM25510-01 and DOE contract 79EV00899. R. Khademi is currently with University of Isfahan, Iran.     

A new approach to analysis of human sweating

In human skin transplanted to the back of 3 strains of immuno-deficient mice the functin of the eccrine sweat glands of the human transplant was tested by topical intradermal application of pilocarine, adrenaline and atropine+pilocarpine. Sweat responses were observed in pre-selected fields of observation by means of video macroscope. The iodine strarch reaction served as an indicator for the appearance of seat sport and permitted the evaluation of areas wetted by sweat in the field of observation. Among 9 animals tested, the hybrids between the CB-17-scid mouse and the BALB/cA-nu mouse (BALB/cA-nu,scid) seemed to exhibit the most consistent seweating response to local pharmacological stimulation. According to histological examination, eccrine sweat glands were preserved in human skin trasplanted into the back skin of the BALB/cA-nu,scid mouse strain. the heterologous, human skin graft provides a novel model permitting, independent of the normal sweat gland innervation, the analysis of moecular receptors of sweat gland cells by which the actions of natural transmitters and pharmacological agents are transduced.