Antigenic correlation between rat thymus and superior cervical ganglion

Summary By using rabbit anti-rat thymocyte and anti-rat superior cervical ganglion sera in cytotoxicity, immunofluorescence and absorption assays, it has been shown that surface membranes of rat thymocytes and cervical ganglion cells (i.e. peripheral nervous tissue cells) contain common antigenic determinants.Acknowledgment. This work was supported by grants from the Republic Research Fund of Serbia, Belgrade.     

The effect of hexamethonium on the secretion induced by sodium deoxycholate in the rat jejunum

Summary The i.v. administration of hexamethonium reduces or abolishes net water secretion induced by sodium deoxycholate in the denervated rat jejunum. The findings suggest that a local nervous reflex may be involved in bile salt-induced intestinal secretion.This research was sponsored by grants from the Swedish Medical Research Council (14X-2855), from the Swedish Society for Medical Sciences, from Magnus Bergvalls Stiftelse and from the Medical Faculty, University of Göteborg.     

Differential removal of insulin-like growth factor binding proteins in rat serum by solvent extraction procedures

Solvent extraction of serum and other biological fluids at an acidic pH is a convenient method to remove the insulin-like growth factor binding proteins (IGFBPs); however, an incomplete removal of IGFBPs can occur and this can potentially interfere with the radioimmunoassay of insulin-like growth factors (IGFs). This study compared the removal of IGFBPs from normal adult rat serum and 5-day old neonatal rat serum by acid-gel filtration, and three solvent extraction methods, i.e., acid-ethanol (AE), acid-cryo-ethanol (ACE) and formic acid-acetone (FAA) treatments by western ligand blotting and slot-blotting analysis. In adult rat serum all three extraction methods removed nearly 75% of total IGFBPs present. For the neonatal serum, AE and FAA were very inefficient in eliminating the IGFBPs, while ACE was somewhat better, as it removed nearly 30% of IGFBPs. Ligand blots of extracted samples showed that IGFBPs of lower size range, 24 to 32 kDa (IGFBP-4, IGFBPs-1 and-2), were resistant to solvent extraction. Acid-gel filtration, in contrast, eliminated >95% of IGF-binding components in both sera. Determination of IGF-I concentrations in samples after gel filtration and extraction methods revealed lower IGF-I values in neonatal serum in acid extracted samples. These data caution against using solvent extractions for IGFBP removal in fetal/neonatal serum.     

Human serum as a culture medium for rat embryos

A comparison was made between the development of post-implantation rat embryos in human serum and rat serum. Protein synthesis (growth) and somite number (differentiation) were retarded in human serum and there was an increased frequency of neural tube defects. Male and female human sera supported development equally well.     

Human serum as a culture medium for rat embryos

Summary A comparison was made between the development of post-implantation rat embryos in human serum and rat serum. Protein synthesis (growth) and somite number (differentiation) were retarded in human serum and there was an increased frequency of neural tube defects. Male and female human sera supported development equally well.     

Glycogen contents in the rat uterus: Response toHibiscus rosa-sinensis Linn. extracts

Summary Ethanolic extracts (50%), as well the benzene extracts, ofH. rosa-sinensis Linn. have reduced significantly the glycogen contents in the uterus of adult rat. Both the extracts exhibit a clear-cut dose-response relation. The inhibition in glycogen contents increases as the dose is increased. Of the 2, benzene extract seems to be more potent. The results are due to antiestrogenic nature of the extracts.This investigation was supported by a grant from Council of Scientific & Industrial Research, New Delhi.     

14-3-2 protein in rat brain synapses

Summary The distribution of the 14-3-2 protein in rat brain synapses was studied by immuno electron microscopy. The protein was localized to the postsynaptic web and to the postsynaptic membrane, but was also prominent both in the presynaptic membrane and in the presynaptic densities. No significant activity was observed in the synaptic vesicles.Acknowledgments. Our sincere thanks to Mrs Ulla Svedin, Eng., for skilled technical assistance. This work was supported by grants from the Swedish Medical Research Council, the Medical Faculty of Göteborg, Tore Nilson's Foundation for Medical Research and by the Swedish-Italian Group of Neurobiology. A. G. received financial support from Consiglio Nazionale delle Ricerche (CNR, ROME).     

The kinetics of estrogen binding to rat α-fetoprotein

Summary Fluid obtained from rat fetuses was utilized to characterize the affinity, number of binding sites, and the association and dissociation rate kinetics of the binding of estradiol and estrone to AFP. Statistical analysis demonstrated no differences when the values for the AFP-estradiol interaction were compared with those obtained for the AFP-estrone interaction. These data demonstrate that rat AFP specifically binds estradiol and estrone with a high capacity, high affinity, and similar binding kinetics.This work was supported by NSF grant PCM-8109847 and by a Grant-in-Aid of Research from Sigma Xi, The Scientific Research Society.     

High K+-induced release of somatostatin from the cortical preparation of rat brain

Summary Release of endogenous somatostatin (SRIF) from the rat cerebral cortical slices incubated in Krebs-bicarbonate buffer was increased from the basal rate of 3.4±0.6% of the total SRIF content in 15 min at [K⁺]_o=5.6 mM, to 13.1±1.6% upon raising the [K⁺]_o to 56.6 mM. The high-K⁺ evoked SRIF release was absent when Ca⁺⁺ in the medium was replaced by Mn⁺⁺. The isolated synaptosomes from rat cerebral cortex contain 13.2±3.1 ng SRIF/mg protein compared to 0.33±0.01 ng/mg protein in the cortical tissue as a whole, suggesting that nerve terminals are the main source of the peptide released upon membrane depolarization.The study was supported by a grant from the Medical Research Council of Canada. Results of this work have been published in part as abstracts: Can. Physiol.9, 45 (1978), and Fedn Proc.37, 665 (1978).The authors are greatly indebted to Dr M. Gotz and the Ayerst Research Laboratories for the most generous supply of the synthetic somatostatin.     

Liminal gastrin does not activate rat stomach histidine decarboxylase

Summary Fasted rats have a low gastric histidine decarboxylase activity. I.v. infusion of heptadecapeptide gastrin for 2 h raised the enzyme activity. Intragastric perfusion with the same dose of gastrin and for the same period of time did not reproduce the effect of circulating gastrin. It is concluded that luminal gastrin, in contrast to circulating gastrin, does not activate rat stomach histidine decarboxylase.This study was supported by the Swedish Medical Research Council (04X-1007, 14X-4144) and by the Albert Påhlsson Foundation.     

Intraluminal bile salt increases rate of firing in afferent fibers from the small intestine of the rat

Summary Perfusion of a rat intestinal segment with a solution containing sodium deoxycholate (8 mM) increases the rate of firing in periarterial afferent nerves from the gut. This observation indirectly supports our earlier proposal that bile salt evokes a net fluid secretion in the small intestine via an activation of the enteric nervous system.This study was supported by grants from the Swedish Medical Research Council (2855), The Medical Council of Swedish Life Insurance Companies and the Faculty of Medicine, University of Göteborg.     

Relationship of specific granules to the natriuretic and diuretic activity of rat atria

Summary The isolation of several fractions from rat atrial homogenates, by the use of differential and sucrose gradient centrifugation, indicates that the diuretic and natriuretic activity is restricted to the fractions rich in specific granules. Our preliminary results suggest that the active substance is a small peptide which is probably different from the natriuretic substance(s) already known.Supported by a group grant given by the Medical Research Council of Canada to the Multidisciplinary Research Group on Hypertension of the Clinical Research Institute of Montreal.Acknowledgments. The authors thank Suzanne Diebold for technical assistance.     

Antigenic correlation between rat brain synaptic vesicles and rat bone marrow B lymphocytes

Summary Rabbit anti-rat brain synaptic vesicle serum reacted with thymocytes and B lymphocytes in cytotoxicity and immunofluorescence assays. Quantitative absorption analysis revealed that this antiserum contained antibodies specific for antigenic determinants on the surface membrane of a subpopulation of rat bone marrow B lymphocytes.This work was supported by the Republic of Serbia Research Fund, Belgrade.     

Stimulation of glycoprotein secretion in dispersed rat submandibular gland acini by cystic fibrosis serum

Summary Acini were enzymatically dissociated from rat submandibular gland and their mucous glycoproteins radiolabelled with¹⁴C-glucosamine. Sera from cystic fibrosis patients stimulated the release of labelled TCA/PTA — insoluble material from the cultured acinar cells to a significantly higher degree than did control sera.This work was supported by the Canadian Cystic Fibrosis Foundation and the Sellers Foundation.     

Antigenic correlation between rat thymus and superior cervical ganglion.

By using rabbit anti-rat thymocyte and anti-rat superior cervical ganglion sera in cytotoxicity, immunofluorescence and absorption assays, it has been shown that surface membranes of rat thymocytes and cervical ganglion cells (i.e. peripheral nervous tissue cells) contain common antigenic determinants.     

The metabolism of the soil fumigant 1,2-dibromo-3-chloropropane in the rat

Summary The soil fumigant 1,2-dibromo-3-chloropropane (I) undergoes hydrolysis in the rat to a series of epoxide metabolites. Alkylation of glutathione by these epoxides produces 2 urinary metabolites identified as the mercapturic acids VI (R=COCH₃) and VII (R=COCH₃). Hydrolysis of the epoxides produces the male antifertility agentsa-chlorohydrin (IX, X=Cl) anda-bromohydrin (IX, X=Br) which are oxidatively metabolized to oxalic acid (XII), thus causing renal damage. These metabolic pathways can explain the toxic nature of the fumigant as a carcinogen, a male chemosterilant and as an agent causing kidney damage.This work was supported in part by the National Health and Medical Research Council of Australia.     

Chromatin condensation in isolated rat hepatocyte nuclei induced by ribonuclease treatment

Summary Ribonuclease treatment of isolated rat hepatocyte nuclei induced a 75% solubilization of hnRNA, a reduction of the qualtity of perichromatin fibrils, and a marked condensation of chromatin.This investigation was supported by grants from C.N.R. (Roma) and by Pallotti's Legacy for Cancer Research.     

Immunoactive TSH in the amniotic fluid of the rat

Summary Amniotic fluid was obtained from 19-day-old rat fetuses by aspiration. Pooled samples measured at 4 different dilutions demonstrated parallelism with standard rat TSH. It is concluded that rat amniotic fluid has TSH immunoactivity.This work was supported by Hong Kong University Research Grant No. 335/034/5727.The authors wish to acknowledge with thanks the gift of rat TSH RIA kit from Dr A. F. Parlow and the Rat Pituitary Programme of NIAMDD.     

Effects of the optical isomers of 2-amino-3-fluoro-1-phenylpropane (monofluoroamphetamine) hydrochloride on uptake and release of dopamine in rat striatum in vitro

Summary The (+)- and (–)-isomers of the monofluorinated amphetamine 2-amino-3-fluoro-1-phenylpropane were prepared and compared for their ability to stimulate release and to inhibit reuptake of radiolabelled dopamine from rat striatal tissue in vitro. The (+)-isomer was much stronger than the (–)-isomer in both cases.Financial support for this project was supplied by the Medical Research Council of Canada, the Alberta Mental Health Research Fund and the Special Services and Research Committee, University of Alberta Hospital.Acknowledgments. Skilled technical assistance was provided by Ms L. Hiob. The authors also wish to thank Dr W.G. Dewhurst, Department of Psychiatry, and Dr D.F. LeGatt, for their advice and comments.     

The effect of age on cardiac output and its distribution in the rat

Summary Cardiac output distribution in the rat was found to be affected by age. Cardiac index and blood flow to the liver, kidneys, skin and skeletal muscle were lower in 11–12 month compared to 3–4 month old rats.Acknowledgments. This work was supported by grants from I.C.I. Pharmaceuticals and Mersey Regional Health Authority (Research Scheme No.338). We wish to thank Mr P.J. Roberts for invaluable technical assistance.