Large conductance calcium-voltage activated potassium (BKca) channels are important modulators in an extensive number of cellular functions, including hormone release from endocrine cells. White adipose tissue is increasingly regarded as the largest endocrine organ in the body, and adipocytes as key regulators of inflammation through the synthesis and secretion of a battery of pro- or anti-inflammatory cytokines. This study set out to characterise the expression of BKca channel and a “gain of function” splice variant STREX in adipocytes, and investigate BKca channels as potential modulators of cytokine release from these cells. Mouse fibroblast 3T3-L1 pre-adipocyte cells were cultured in DMEM with 10% foetal bovine serum (FBS), and differentiated into mature adipocytes by replacing cell growth media with 10% FBS DMEM supplemented with 0.5 mM 3-isobutyl-1-methylated, 0.25 µm dexamethasone and 1 µg/ml insulin and incubated for 48 hours. Thereafter, cells were treated with media with 10% FBS, 1 µg/ml insulin complemented DMEM for up to 10 days. Total RNA was extracted on day 0, 4, 8, 10 and 10+ (n = 5 per group), reverse transcribed and levels of BKca and STREX mRNA, and the pro-inflammatory cytokines tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β mRNA, and the anti-inflammatory cytokine IL-10 mRNA measured using real-time PCR. The effects of treating mature adipocytes (day 10+) for 24 hours with the BKca channel agonist NS 1619 (20 µg), or channel blocker iberiotoxin (IBX; 10 ng), or drug-vehicle on gene expression were also analysed. Values are means ± S.E.M., compared by ANOVA. BKca and STREX mRNA and all four cytokines examined were found to be constitutively expressed in both pre- and mature adipocytes. In mature day 10 adipocytes, a 2 fold up-regulation in BKca and 32 fold STREX mRNA expression was observed. TNF-α, IL-6 and IL-1β mRNA were induced in mature day 10 adipocytes (all P < 0.01 vs. day 0); IL-10 mRNA levels were unchanged. Following treatment with IBX, futher up-regulation in expression of TNF-α (4 fold), IL-6 (2.7 fold) and IL-1β (6 fold), but not IL-10 mRNA were detected (P < 0.01 vs. vehicle and NS 1619 treated cells). These data show that BKca channel and splice variant STREX are expressed in adipocytes. Furthermore, adipocyte derived pro-inflammatory cytokines were induced by blockade of BKca channel activity. These findings suggest that BKca channels may play a role in regulating the inflammatory response associated with obesity