In another model, Kelly and colleagues demonstrated pseudo islets containing MIN-6, TC1.9, and TGP52 WHI-P97 cells that secreted similar amounts of insulin in comparison to that of MIN-6 only pseudo islets . mice islets in vivo where cells cluster in the core and cells are localized at the periphery. During the C cell co-culture, the gene expression of glucagon (Gcg) decreased significantly. We conclude that islet cells suppress glucagon secretion from cells, apparently via direct cell-to-cell contact, of which the molecular mechanism needs further verification. 0.05 was considered a significant difference. We have normalized insulin and glucagon secretion data on a per cell basis, and adjusted gene expression data according to the ratio of and cells (1:3). 3. Results 3.1. GSIS of Mono- and Co-Cultured MIN-6 and -TC1-6 Cells The effects on GSIS of mono- and co-cultured MIN-6 and -TC1-6 cells are presented in Figure 1. After a 72 h incubation in 5.5 mM of glucose (A), co-cultured cells tended to secrete less insulin compared to mono MIN-6 cells when stimulated with either low or high glucose (= 0.41 and 0.07). Mono MIN-6 cells and co-cultured cells showed no difference in GSIS after incubation in 11.1 (B) or 25 mM (C) glucose. Following a 72 h incubation in 5.5 mM and 11.1 mM glucose, high glucose tended to stimulate GSIS more than low glucose for both mono MIN-6 cells and co-cultured cells, even though significance WHI-P97 was only observed in co-cultured cells incubated in 11.1 mM ( 0.005). High glucose significantly prompted insulin release by approximately 2-fold compared to low glucose, both from mono MIN-6 and co-cultured cells after being incubated in 25 mM glucose for 72 h. Open in a separate window Figure 1 Insulin secretion from mono- or co-cultured MIN-6 and -TC1-6 cells when stimulated with low (1 mM) or high (18 mM) glucose after 72 h incubation in (A) 5.5, (B) 11.1, or (C) 25 mM glucose, respectively. (D) Insulin secretion from MIN-6 cells when stimulated with high glucose after 72 h incubation in 5.5, 11.1, or 25 mM glucose, respectively. (E) Insulin secretion from co-cultured cells when stimulated with high glucose after 72 h incubation in 5.5, 11.1, or 25 mM glucose, respectively. Data are presented as the mean SEM of 18 samples per condition from three independent experiments. ** 0.01, **** 0.0001. With high stimulation, the GSIS levels of both mono MIN-6 and co-cultured cells incubated in 25 mM glucose was higher than those incubated in 5.5 mM or 11.1 mM glucose ( 0.0001) (Figure 1D,E). Meanwhile, there were no significant differences between the cells incubated in 5.5 mM and 11.1 mM glucose. Mono-cultured -TC1-6 cells secreted traces of insulin under all conditions. 3.2. Glucagon Secretion of WHI-P97 Mono- and Co-Cultured MIN-6 and -TC1-6 Cells The glucose-dependent effects on glucagon secretion from mono- and co-cultured MIN-6 and -TC1-6 cells are shown in Figure 2. After 72 h incubation in 5.5 mM glucose (A), co-culture of MIN-6 and -TC1-6 cells tended to suppress glucagon secretion, albeit not significantly (= 0.17 and 0.11), when stimulated with low and high glucose. Compared to mono -TC1-6 cells, co-cultured cells demonstrated a clear decrease in glucagon after a 72 h exposure in 11.1 (B) or 25 mM (C) glucose, with an approximately 2-fold suppression in the latter ( 0.01). Low or high glucose stimulation had no impact on glucagon secretion under any of the conditions WHI-P97 (not Mouse monoclonal to SMN1 significant). Open in a separate window Figure 2 Glucagon secretion from mono- or co-cultured MIN-6 and -TC1-6 cells when stimulated with low (1mM) or high (18 mM) glucose after 72 h incubation in (A) 5.5, (B) 11.1, or.