1,721,726 research outputs found
Pathogenesis of PCOS: From Metabolic and Neuroendocrine Implications to the Choice of the Therapeutic Strategy
No full textPCOS is a quite frequent reproductive disease that affects 5–20% of the female population. Though specific diagnostic criteria have been established, probably they need an update according to the new insights recently ascertained, that is, insulin resistance (IR) and compensatory hyperinsulinemia. In addition, new specific insights have been demonstrated in animal models of PCOS that suggest a clear role of a neuroendocrinological impairment that might occur during prenatal life and/or after birth affecting the regular function of the reproductive axis. All these aspects suggest that PCOS might have a certain grade of epigenetic origins that might be implemented by familial predisposition to specific dismetabolic diseases such as diabetes. We will try to focus on these aspects to give an update on the putative therapeutical possibilities
Non-genomic actions of sex steroid hormones
No full textSteroid hormone receptors have been traditionally considered to act via the regulation of transcriptional processes, involving nuclear translocation and binding to specific response elements, and ultimately leading to regulation of gene expression. However, novel non-transcriptional mechanisms of signal transduction through steroid hormone receptors have been identified. These so-called 'non-genomic' effects do not depend on gene transcription or protein synthesis and involve steroid-induced modulation of cytoplasmic or cell membrane-bound regulatory proteins. Several relevant biological actions of steroids have been associated with this kind of signaling. Ubiquitous regulatory cascades such as mitogen-activated protein kinases, the phosphatidylinositol 3-OH kinase and tyrosine kinases are modulated through non-transcriptional mechanisms by steroid hormones. Furthermore, steroid hormone receptor modulation of cell membrane-associated molecules such as ion channels and G-protein-coupled receptors has been shown. TIssues traditionally considered as 'non-targets' for classical steroid actions are instead found to be vividly regulated by non-genomic mechanisms. To this aim, the cardiovascular and the central nervous system provide excellent examples, where steroid hormones induce rapid vasodilatation and neuronal survival via non-genomic mechanisms, leading to relevant pathophysiological consequences. The evidence collected in the past Years indicates that target cells and organs are regulated by a complex interplay of genomic and non-genomic signaling mechanisms of steroid hormones, and the integrated action of these machineries has important functional roles in a variety of pathophysiological processes. The understanding of the molecular basis of the rapid effects of steroids is therefore important, and may in the future turn out to be of relevance for clinical purposes
Polycystic Ovary Syndrome: From Contraception to Hormone Replacement Therapy
No full textPolycystic ovary syndrome (PCOS) is a common disease based on a combination of various endocrine impairments. The use of hormonal treatments permits the aesthetic disturbances to be counteracted (acne, hirsutism, alopecia), but greater attention has to be given to insulin resistance, which may induce more severe diseases, such as diabetes. The use of oral contraceptives is helpful, but a lifestyle change is considered essential so as to improve the natural ability to resist disease affecting the circulation and metabolism. When the menopausal transition starts, greater attention is given to those PCOS patients who demonstrated insulin resistance during their fertile life. The use of hormone replacement therapy is often suggested as it has been proven to be beneficial
Amyloid-beta Induced Deregulation of Calcium Homeostasis in Glial Cells in an Innovative Model of Alzheimer’s Disease
No full textRiccardo Genazzani A Smoking habit, immune suppression, oral contraceptive use, and hormone replacement therapy use and cervical carcinogenesis: a review of the literature
No full textContraception as prevention and therapy: sex steroids and the brain
No full textThe brain is one of the specific target tissues for sex steroid hormones. Estrogens, progestins and androgens are able to induce several effects in brain areas of the central nervous system (CNS), through the binding with specific receptors. Specific receptors for gonadal steroids have been identified in the amygdala, hippocampus, basal forebrain cortex, cerebellum, locus ceruleus, midbrain rafe nuclei, glial cells, pituitary gland, hypothalamus and central gray matter.At the hypothalamic level, the principal target for sex steroids is those neurons producing the pulsatile release of the gonadotropin releasing hormone (GnRH), localized in the mediobasal hypothalamus and the arcuate nucleus.The GnRH release depends on the complex and co-ordinated interrelationships among gonadal steroids, pituitary gonadotropins and neuroactive transmitters, such as the noradrenaline, dopamine, opioid peptides (β-endorphin), acetylcholine, serotonin, γ-aminobutyrric acid, corticotropin releasing hormone and neuropeptide Y.The interplay of these control mechanisms is governed by peripheral feedback signals; as well as the input from higher brain centers they may modify the GnRH secretion. The anterior pituitary lobe is the best known target tissue for endogenous or exogenous sex steroid hormones, because it is possible to detect luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in blood, as the expression of the pituitary cells' activity. The synthesis and release of FSH and LH by the gonadotropic cells depend upon the peripheral control of gonadal hormones and the GnRH hypothalamic release. In summary, during a woman's reproductive life, the interaction between neurotransmitters, neuropeptides and gonadal hormones modulates the hypothalamo-pituitary-gonadal axis by acting selectively on the synthesis and release of GnRH and of pituitary gonadotropic hormones.The increased use of oral contraceptives in the last 30 years and, in general, of sex steroid hormone derivative therapies, has led to the study of the biochemical and metabolic properties of the different progestin molecules available in hormonal therapies by focusing attention on the interactions between estrogens and progestins in the modulation of the hypothalamo-pituitary-gonadal axis.The different kinds of estrogen and progestin molecules used in oral contraceptives inhibit the ovulatory process and may interfere with other sex steroid hormone receptors, thus exerting multiple effects in each target tissue
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