Expression of the c-Harvey ras oncogene alters peptide synthesis in the neurosecretory cell line AtT20

Rhes is involved in striatal function

The development and the function of central nervous system depend on thyroid hormones. In humans, the lack of thyroid hormones causes cretinism, a syndrome of severe mental deficiency. It is assumed that thyroid hormones affect the normal development and function of the brain by activating or suppressing target gene expression because several genes expressed in the brain have been shown to be under thyroid hormone control. Among these, the Rhes gene, encoding a small GTP-binding protein, is predominantly expressed in the striatal region of the brain. To clarify the role of Rhes in vivo, we disrupted the Rhes gene by homologous recombination in embryonic stem cells and generated mice homozygous for the Rhes null mutation (Rhes(-/-)). Rhes(-/-) mice were viable but weighed less than wild-type mice. Furthermore, they showed behavioral abnormalities, displaying a gender-dependent increase in anxiety levels and a clear motor coordination deficit but no learning or memory impairment. These results suggest that Rhes disruption affects selected behavioral competencies.

Changes in glucose transport activities in mammary adenocarcinoma of dogs

The activities of D-glucose transport (D-GT) and cytosolic enzymes were significantly higher in mammary adenocarcinoma of dogs than in mammary gland from normal dogs. The activities of D-GT in adenocarcinoma were over three-and-a-half times higher than in the controls. The K(m) value of the D-GT activity for glucose in both the adenocarcinoma and normal mammary gland was approximately 0.9 mM. The activities of the key glycolytic enzymes, hexokinase and pyruvate kinase, in the adenocarcinoma were also more than three-and-a-half times higher than in the controls. The increased activities of D-GT are considered to be accompanied by an acceleration of glucose utilisation in the adenocarcinoma of dogs.