New insights into the endocrine and metabolic roles of dopamine D2 receptors gained from the Drd2 mouse.

Dopamine D2 receptor (D2R) participation in prolactin regulation is well documented, but the role of D2Rs in the control of other hormones involved in growth, food intake and glucose metabolism has not been extensively studied. The study of D2R knockout mice (Drd2(-/-)) puts forward new insights into the role of the D2R in growth hormone (GH)-releasing hormone-GH regulation, peptides involved in food intake, glucose homeostasis, as well as in prolactinoma development. The expected phenotype of chronic hyperprolactinemia and prolactinoma development was found in the Drd2(-/-) mouse, and this model constitutes a valuable tool in the study of dopamine-resistant prolactinomas.

Differential localization to cytoplasm, nucleus or P-bodies of yeast PKA subunits under different growth conditions.

Our aim in this work was to further characterize the complexity and specificity of the three different isoforms (Tpk1, Tpk2 and Tpk3) of the catalytic and regulatory (Bcy1) subunits of PKA in Saccharomyces cerevisiae. We thus analyzed the subcellular localization of the PKA subunits in living cells by using strains carrying GFP (green fluorescent protein) fused to each PKA subunit. During exponential growth on glucose, both Bcy1 and Tpk2 localized in the nucleus, whereas Tpk1 and Tpk3 showed a mixed pattern of nucleo-cytoplasmic localization.