Various hormonal and monoaminergic systems play determinant roles in the regulation of several cytochromes P450 (P450s) in the liver. Growth hormone (GH), prolactin, and insulin are involved in P450 regulation, and their release is under dopaminergic control. This study focused on the role of D 2 -dopaminergic systems in the regulation of the major drug-metabolizing P450s, i.e., CYP3A, CYP2C, and CYP2D. Blockade of D 2 -dopaminergic receptors with either sulpiride (SULP) or 4-(4-chlorophenyl)-1-(1H-indol-3-ylmethyl)piperidin-4-ol (L-741,626) markedly down-regulated CYP3A1/2, CYP2C11, and CYP2D1 expression in rat liver. This suppressive effect appeared to be mediated by the insulin/ phosphatidylinositol 3-kinase/Akt/FOXO1 signaling pathway. Furthermore, inactivation of the GH/STAT5b signaling pathway appeared to play a role in D 2 -dopaminergic receptor-mediated down-regulating effects on these P450s. SULP suppressed plasma GH levels, with subsequently reduced activation of STAT5b, which is the major GH pulse-activated transcription factor and has up-regulating effects on various P450s in hepatic tissue. Levels of prolactin, which exerts down-regulating control on P450s, were increased by SULP, which may contribute to SULP-mediated effects. Finally, it appears that SULP-induced inactivation of the cAMP/protein kinase A/cAMP-response element-binding protein signaling pathway, which is a critical regulator of pregnane X receptor and hepatocyte nuclear factor 1␣, and inactivation of the c-Jun N-terminal kinase contribute to SULP-induced down-regulation of the aforementioned P450s. Taken together, the present data provide evidence that drugs acting as D 2 -dopaminergic receptor antagonists might interfere with several major signaling pathways involved in the regulation of CYP3A, CYP2C, and CYP2D, which are critical enzymes in drug metabolism, thus affecting the effectiveness of the majority of prescribed drugs and the toxicity and carcinogenic potency of a plethora of toxicants and carcinogens.

Background Senior individuals are particularly vulnerable to influenza. Research suggests that protection against the virus and its transmission in this high-risk group of the population can be achieved by active immunization against the pathogen. Aims To explore and analyze the attitudes, knowledge and behavior of people over the age of 60 on influenza vaccination. Population and methods This cross-sectional survey included people over the age of 60 who were eligible candidates for the influenza vaccine from 3 regions from Northern and 1 region from Southern Greece. A self-completed questionnaire based upon the Theory of Planned Behaviour, the Motivation for Vaccination (MoVac-flu) and the Vaccination Advocacy Scale (MovAd) was administered to the participants. Demographic characteristics and information about health status were also obtained. Results The final sample included 318 participants with mean age of 70.7 years. More than half of the participants (56.6%) had received a flu vaccine in 2018 while 50.8% received it annually in previous years. Behavioral (p < 0.001), normative (p < 0.001), and control beliefs (p < 0.001), promoted the uptake of the vaccine and the increased intention score (p < 0.001) was associated with increased probability of vaccination. Greater age (p = 0.001) and frequent visits to the doctors (p = 0.003) had a positive influence upon the uptake of the vaccine. Conclusions Only a small proportion of those over the age of 60 had received the influenza vaccine. This finding is worrying, as it indicates the impact that a future outbreak of seasonal influenza could exert upon vulnerable groups. There is an urgent need for further, better and more evidence-based information from healthcare professionals to achieve greater vaccination coverage in the community.

Oleuropein (OLE), a main constituent of olive, exhibits antioxidant and hypolipidemic effects, while it reduces the infarct size in chow- and cholesterol-fed rabbits. Peroxisome proliferator-activated receptor α (PPARα) has essential roles in the control of lipid metabolism and energy homeostasis. This study focused on the mechanisms underlying the hypolipidemic activity of OLE and, specifically, on the role of PPARα activation in the OLE-induced effect. Theoretical approach using Molecular Docking Simulations and luciferase reporter gene assay indicated that OLE is a ligand of PPARα. The effect of OLE (100 mg/kg, p.o., per day, ×6 weeks) on serum triglyceride (TG) and cholesterol levels was also assessed in adult male wild-type and Ppara-null mice. Molecular Docking Simulations, Luciferase reporter gene assay and gene expression analysis indicated that OLE is a PPARα agonist that up-regulates several PPARα target genes in the liver. This effect was associated with a significant reduction of serum TG and cholesterol levels. In contrast, OLE had no effect in Ppara-null mice, indicating a direct involvement of PPARα in the OLE-induced serum TG and cholesterol reduction. Activation of hormone-sensitive lipase in the white adipose tissue (WAT) and the liver of wild-type mice and up-regulation of several hepatic factors involved in TG uptake, transport, metabolism and clearance may also contribute in the OLE-induced TG reduction. In summary, OLE has a beneficial effect on TG homeostasis via PPARα activation. OLE also activates the hormone sensitive lipase in the WAT and liver and up-regulates several hepatic genes with essential roles in TG homeostasis.