Underlying mechanisms mediating the antidepressant effects of estrogens.

BACKGROUND: There is an increased risk for depressive symptoms and affective disorders in individuals who experience drastic drops or fluctuations of gonadal hormones. Moreover, clinical studies indicate that estrogens have the potential to be effective in treating depression. SCOPE OF THE REVIEW: Possible underlying mechanisms for the antidepressant activity of estrogens are reviewed and discussed. MAJOR CONCLUSIONS: Estrogens exert their antidepressant activity via a multimodal mechanism of action by regulating several pathways and functions associated with antidepressive effects. Estrogens increase serotonergic activity by regulating the synthesis and degradation of serotonin, as well as spontaneous firing of the serotonergic neurons in the raphe nuclei. Both pre- and postsynaptic serotonin receptors are shown to be regulated by estrogens. In addition, estrogens are neurotrophic and promote neuroplasticity and neurogenesis. Similar effects are also observed after treatment with current antidepressant therapies. However in stark contrast to current therapies which must be administered chronically to produce an effect, the responses to estrogens are often observed after a single dose. Many of these estrogenic effects, including antidepressant and anxiolytic responses in behavioral models in rodents, appear to be mediated via the estrogen receptor beta subtype. GENERAL SIGNIFICANCE: The rapid onset of action combined with the multifactorial mechanism of action of estrogens indicates that estrogen treatment could complement currently available therapies for depression. Considering safety aspects, selective estrogen receptor beta agonists would probably be the optimal estrogenic therapy.

Synthesis and activity of novel bile-acid conjugated glucocorticoid receptor antagonists.

A series of potent steroidal glucocorticoid receptor antagonists has been discovered. After conjugation to cholic acid, the compounds retained an affinity for GR in vitro and had modest in vivo efficacy.

Estrogen action in mood and neurodegenerative disorders: estrogenic compounds with selective properties-the next generation of therapeutics.

In this review, estrogenic effects in depression, anxiety, and neurodegenerative disorders are summarized. Moreover, preclinical findings from in vitro and animal models are discussed. There is a correlation between decreased estrogen levels (e.g., premenstrually, during the postpartum period, and perimenopausally) and increased anxiety and depressive symptoms. Several studies show beneficial effects of estrogen treatment in women with anxiety and depressive symptoms. Recent data indicate that the estrogen receptor (ER) beta appears to be a major mediator of estrogenic effects in depression and anxiety. Additionally, both preclinical and clinical findings suggest that activation of estrogen receptors have an important role in neuroprotective and neurodegenerative processes in the mammalian central nervous system (CNS).

Liver-selective glucocorticoid antagonists: a novel treatment for type 2 diabetes.

Hepatic blockade of glucocorticoid receptors (GR) suppresses glucose production and thus decreases circulating glucose levels, but systemic glucocorticoid antagonism can produce adrenal insufficiency and other undesirable side effects. These hepatic and systemic responses might be dissected, leading to liver-selective pharmacology, when a GR antagonist is linked to a bile acid in an appropriate manner. Bile acid conjugation can be accomplished with a minimal loss of binding affinity for GR. The resultant conjugates remain potent in cell-based functional assays. A novel in vivo assay has been developed to simultaneously evaluate both hepatic and systemic GR blockade; this assay has been used to optimize the nature and site of the linker functionality, as well as the choice of the GR antagonist and the bile acid. This optimization led to the identification of A-348441, which reduces glucose levels and improves lipid profiles in an animal model of diabetes.