Modulation of Cytokines, Adiponectin and Leptin Expression in Mature Bovine Adipocytes by Serotonin

Serotonin (5-HT) is an important neurotransmitter in the mammalian central nervous system (CNS) and synthesized from gastric and intestinal mucosa. It is involved in numerous physiological and behavioral disorders such as major depression, anxiety, schizophrenia, obesity and drug addiction. Here we tested the immuno-modulatory effects of serotonin on various adipokines expression in mature bovine adipocytes. Isolated mature adipocytes were incubated with either lipopolysaccharide LPS (1pg/ml), serotonin 1pM, or LPS for 2 h then with serotonin for 24 h. Using RT-PCR analysis, various adipokines that are secreted and expressed in adipocytes was examined. The results showed that treatment of cells by LPS stimulated the expression of IL-10, IL-8, SOC3, adiponectin and leptin mRNA but has an inhibitory effect on mRNA expression of TNF-a and PPAR-y. Serotonin treatment has no effect on IL-10, TNF-a, IL-8 and SOC3 mRNA but stimulated adiponectin, leptin and LPL expression. Prior treatment of cells by LPS (2h) then serotonin for 24 h induced additive stimulatory effect on IL-1 and IL-8 expression but inhibited LPS induced adiponectin, leptin and LPL expression. The results indicate that serotonin has both immuno-modulatory effect during infection and inflammation, and an anti-obesity effect through its effect on adiponectin and leptin in normal state. Those effects probably induced at the transcriptional level of both PPAR-y and LPL in bovine adipocytes