Inhibitory effects of LHRH on LH receptors in the rat testis]

A single injection of LHRH to the adult male rat, as of its analog [D-Ala6, des-Gly-NH102] LHRH ethylamide, resulted in a marked decrease in LH receptors in the tests. Plasma testosterone level and the weight of the seminal vesicles and prostate were also decreased after treatment. These data demonstrate that LHRH can decrease the sensitivity of LH receptors and testicular function in the rat.     

The effects of age and nutritional state on m.e.p.p. amplitude

Summary A quantitative restriction of food intake for 7 days reduced the amplitude of spontaneous miniature endplate potentials by about 1/3 in rats aged 30 days but not in rats aged 110 days.I would like to thank Dr D. V. Roberts for encouragement and advice and the Medical Research Council and the Muscular Dystrophy Group of Great Britain for financial support.     

Location of MHC-encoded transporters in the endoplasmic reticulum and cis-Golgi.

Immune recognition of intracellular proteins is mediated by major histocompatibility complex (MHC) class I molecules that present short peptides to cytotoxic T cells. Evidence suggests that peptides arise by cleavage of proteins in the cytoplasm and are transported by a signal-independent mechanism into a pre-Golgi region of the cell, where they take part in the assembly of class I heavy chains with beta 2-microglobulin (reviewed in refs 5-7). Analysis of cells that have defects in class I molecule assembly and antigen presentation has shown that this phenotype can result from mutations in either of the two ABC transporter genes located in the class II region of the MHC. This suggested that the protein complex encoded by these two genes transports peptides from the cytosol into the endoplasmic reticulum. Here we report additional evidence by showing that the transporter complex is located in the endoplasmic reticulum membrane and is probably oriented with its ATP-binding domains in the cytosol.     

1-methyl-4-phenylpyridine is neurotoxic to the nigrostriatal dopamine pathway

Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is neurotoxic to cerebral dopaminergic neurones in several animal species, and can cause parkinsonism in man. The mechanism of this action may be indirect. MPTP is oxidized in the brain to a pyridinium species, 1-methyl-4-phenylpyridine (MPP+)6. This oxidation is greatly decreased by inhibition of monoamine oxidase B6, as are the biochemical effects of MPTP in the mouse and its neurotoxicity in the monkey. We now show that MPP+ exerts a powerful neurotoxic action on the nigrostriatal dopamine system of the rodent.     

LDH isozyme pattern in induced muscle disease (coxsackie group a virus infection)

Résumé Le zymogramme des LDH du muscle de souriceau nouveau-né souffrant de myosite diffuse causée par le virus de Coxsackie Groupe A est semblable à celui du souriceau sain de même âge, suggérant qu'un zymogramme anormal des LDH dans les affections musculaires n'est pathognomonique que chez certaines espèces.