Control of obesity inA vy /a mice by 5α-androstan-17-one

Summary Treating VY/WfL-A ^vy /a mice with 5-androstan-17-one, a mammalian glucose-6-phosphate dehydrogenase inhibitor, prevented the mice from becoming obese. The weight difference between treated and controlA ^vy /a mice was mainly due to a decreased accumulation of triacylglycerol. The compound did not suppress appetite, had no detectable toxicity and did not affect the lipogenesis rates in the liver and carcass. The weight-controlling effect of 5-androstan-17-one inA ^vy /a mice was reversible upon withdrawal of treatment.The authors wish to thank Mr W.R. Gibson and Drs C.G. Culbertson and P.N. Harris for performing the pathological examinations.     

Genetic basis of susceptibility for development of neoplasms following treatment with N-methyl-N-nitrosourea (MNU) or X-rays in the platyfish/swordtail system

Summary Specific genotypes of the xiphophorine fish develop neoplasms following treatment with N-methyl-N-nitrosourea or X-rays. Several of these neoplasms can be related to the presence of specific chromosomes. The implications of these findings are discussed.Supported by Deutsche Forschungsgemeinschaft through Sonderforschungsbereich 103 Zellenergetik und Zelldifferenzierung, Marburg (projects C 9 and C 10), and by Justus-Liebig-Universität Giessen. We are indebted to Prof. K. Frese, Veterinär-Pathologisches Institut, Giessen and Dr H. D. Mennel, Pathologisches Institut, Freiburg, for their help in the classification of neoplasms. We furthermore thank K. Klinke for breeding the fish. Dedicated to Prof. C. Kosswig on the occasion of his 75^th birthday.The paper contains parts of the dissertations of S. Abdo, J. Haas and G. Kollinger.supported by the Egypt ministry of education.     

Action ofβ-(4-chlorophenyl-GABA) on uptake and metabolism of GABA in different subcellular fractions of rat brain

Summary -(4-chlorophenyl)-GABA, a GABA mimetic compound, acts as an inhibitor of GABA metabolism in both synaptosomal and extrasynaptosomal compartments. It has no significant action on GABA or Glu uptake by synaptosomes.     

Effect of dibutyryl cyclic AMP and analogs on the rate of contractions of myocytes in culture

Summary ²O,⁶N-butyryl, 3, 5-cyclic monophosphate (dibu cAMP) when added to fetal rat heart cells in culture inhibits myocyte contraction. This inhibition is 100, 84 and 51% complete when the dibu cAMP concentration used is 2, 0.2 and 0.02 mM, respectively. The potency of dibu cAMP derivatives in myocyte contraction inhibition follows the order, dibu cAMP> ⁶N-bu cAMP> ²O-bu cAMP=AMP>butyrate. The inhibition caused by the first three chemicals is greater than 70%.The author was a Moss Heart Fellow and acknowledges the technical assistance of Ms Martha Peet. This work was supported in part by the American Heart Association, National Science Foundation and American Cancer Society.     

Effect of beta-adrenergic blockade on intramuscular triglyceride mobilization during exercise

Summary It was shown in the rat that mobilization of intramuscular triglyceride during exercise is controlled by the adrenergic system.Acknowledgments. The work was supported by the Polish Academy of Sciences, grant No. 10.4.2.01.3.2.     

Nuclear lamellae in the germ-line cells of gall midges (Cecidomyiidae,Diptera)

Summary Lamellar structures in oogonial and spermatogonial cells of gall midges were found to form a complicated system of intranuclear compartments inside which all heteropycnotic chromosomes present in the germ-line cells of these insects are located. In this way, the heteropycnotic S-chromosomes are separated by the nuclear lamellae from the remaining, decondensed chromosomes (E-chromosomes) of the interphase germ-line nucleus.This investigation was supported in part under Contract DPKBN/52/76-II.1.3.10. with the Polish Academy of Sciences.     

Polyoxin fungicides: Demonstration of insecticidal activity due to inhibition of chitin synthesis

Summary Polyoxin A, a selective inhibitor of chitin synthetase, was found to be insecticidal when injected into the abdomen of grasshoppers nymphs, with an LD₅₀ of 1.26±0.20 g per insect. Symptomatology and the absence of any toxicity toward adult insects indicate that toxicity is due to interference with cuticle deposition.Acknowledgment. I thank Henry Bork for his expert technical assistance.     

Cytotoxicity of mouse peritoneal cells after alloimmunization]

CBA Mice were immunized by two intraperitoneal injections of 30 X 10(6) DBA/2 or C57BL/6 spleen cells at days--12 and--2. Peritoneal cell population was obtained at day zero by washing the peritoneal cavity of Mice. Adherent cells were then separated using a 2 hrs. incubation in "Falcon" plates followed by washing. This macrophage-rich peritoneal cell population was found nonspecifically cytotoxic against 51Cr labeled tumoral target cells: P815 X DBA/2 mastocytoma cells, EL4 X C57BL/L lymphoma cells and spontaneous lymphoma AKR cells (same H--2k as CBA). This adherent peritoneal cell cytoxicity was demonstrated after 24 hrs. incubation with the target cells. It was found in nonspecific combination as well as when using target cells syngeneic to the donor. These findings suggest that adherent peritoneal cell cytotoxicity could be at least partly due to macrophages and result from factor (s) released by sensitized lymphocytes in vivo in the same way as has been previously demonstrated in vitro.     

Spatial conformation of human serotransferrin glycans]

The construction of molecular models for the human serotransferrin glycans shows that they present one compact section linked to the protein and constituted by the pentasaccharide alpha-Man-(1 leads to 3)-[alpha-Man-(1 leads to 6)]-beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4)-beta-GlcNAc-(1 leads to)-Asn to which are attached two "antennae" consisting of the trisaccharide alpha-NANA-(2 leads to 6)-beta-Gal-(1 leads to 4)-beta-GlcNAc. The trisaccharide sequence beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4)-beta-GlcNAc adopts a flat and rigid conformation, stabilised by hydrogen bonds. In contrast, the sequence alpha-NANA-(1 leads to 6)-beta-Gal-(1 leads to 4)-beta-GlcNAc-(1 leads to 2)-alpha-Man takes up a helical configuration. The two "antennae" can be disposed on the pentasaccharide core to give two possible configurations, one Y-shaped and the other T-shaped. In both cases, the general conformation of the glycans is perfectly compatible with their postulated role as a recognition signal.     

Variations au cours de la journée de l'incorporation in vivo de la leucine tritiée dans les protéines du cervelet et du cerveau du jeune rat normal et hypothyro?dien. Daily variations of the in vivo [3H] leucine incorporation into the cerebellar and cerebral proteins of the normal and hypothyroid young rat [(author's transl)

In the normal and hypothyroid 6-day-old rat, the specific radioactivity (RSA) and the relative RSA (ratio of the RSA to the [3H] lecine concentration of the acido soluble phase) of the cerebral and cerebellar proteins, changes during the day synchronally. They show a maximum at 15.00 h and a minimum at 0.300 h. At all stages studied, these values are significantly lower in the hyothyroid animals than in normal ones.