DLK1/PREF1 regulates nutrient metabolism and protects from steatosis.

Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance and obesity, as well as progressive liver dysfunction. Recent animal studies have underscored the importance of hepatic growth hormone (GH) signaling in the development of NAFLD. The imprinted Delta-like homolog 1 (Dlk1)/preadipocyte factor 1 (Pref1) gene encodes a complex protein producing both circulating and membrane-tethered isoforms whose expression dosage is functionally important because even modest elevation during embryogenesis causes lethality.

Novel control by the CA3 region of the hippocampus on neurogenesis in the dentate gyrus of the adult rat.

The dentate gyrus is a site of continued neurogenesis in the adult brain. The CA3 region of the hippocampus is the major projection area from the dentate gyrus. CA3 sends reciprocal projections back to the dentate gyrus.

The roles of BDNF, pCREB and Wnt3a in the latent period preceding activation of progenitor cell mitosis in the adult dentate gyrus by fluoxetine.

The formation of new neurons continues into adult life in the dentate gyrus of the rat hippocampus, as in many other species. Neurogenesis itself turns out to be highly labile, and is regulated by a number of factors. One of these is the serotoninergic system: treatment with drugs (such as the SSRI fluoxetine) markedly stimulates mitosis in the progenitor cells of the dentate gyrus.

Brain-derived neurotropic factor and neurogenesis in the adult rat dentate gyrus: interactions with corticosterone.

Flattening the diurnal corticosterone rhythm prevented the stimulating action of L-NAME (a nitric oxide synthase, NOS, inhibitor) on progenitor cell proliferation in the dentate gyrus in Lister-Hooded adult male rats. The increased expression of brain-derived neurotrophic factor (BDNF) and trkB mRNA in the dentate gyrus which otherwise occurred after L-NAME was also prevented by clamping the corticoid rhythm in adrenalectomized rats, but was restored by daily additional injections of corticosterone (which replicates the diurnal rhythm). Unilateral infusions of BDNF into the lateral ventricle increased proliferation in the dentate gyrus on the side of the infusion, but this was not observed following implantation of subcutaneous corticosterone, which flattened the diurnal corticosterone rhythm.

Hypothalamic gene expression following ghrelin therapy to gastrectomized rodents.

We investigated whether ghrelin depletion (by gastrectomy surgery) and/or treatment/replacement with the gastric hormone ghrelin alters the expression of key hypothalamic genes involved in energy balance, in a manner consistent with ghrelin's pro-obesity effects. At 2 weeks after surgery mice were treated with ghrelin (12 nmol/mouse/day, sc) or vehicle for 8 weeks. Gastrectomy had little effect on the expression of these genes, with the exception of NPY mRNA in the arcuate nucleus that was increased.

Interactions between nitric oxide and corticosterone in the regulation of progenitor cell proliferation in the dentate gyrus of the adult rat.

It is well established that L-NAME, a generic NOS inhibitor, stimulates neurogenesis in the dentate gyrus of the adult rat and corticosterone reduces it. These experiments explore the interaction between L-NAME and corticosterone. L-NAME (50 mg/kg), as expected, increased proliferation, but also lowered plasma corticosterone levels.