Insulin, Glucagon, and Somatostatin Receptors on Cultured Cells and Clones from Rat Islet Cell Tumor

Abstract

Cells grown in culture from rat islet cell tumor (parent cells) and clones obtained from them were used in this study. Parent cells secreted primarily insulin and somatostatin with very small quantities of glucagon. The clones, based on hormone content and secretion, were divided into three phenotypic groups: insulin secreting, somatostatin secreting, and nonsecreting clones. Specific receptors for insulin, glucagon, and somatostatin were demonstrated on parent cells and clones. Parent cells bound 4.12 +/- 0.46% insulin, 2.11 +/- 0.29% glucagon, and 2.49 +/- 1.24% somatostatin per 2 x 10(6) cells. Characteristic hormone binding patterns were observed in insulin secreting versus somatostatin secreting clones. Insulin secreting versus somatostatin secreting clones. Insulin secreting clones bound less insulin than somatostatin and other noninsulin-secreting clones (P less than 0.02). In contrast, somatostatin secreting clones bound more somatostatin than non-somatostatin-secreting clones (P less than 0.05). Somatostatin-secreting clones had a significantly greater number of receptors for all three hormones. The difficulties involved in the interpretation of the quantitative aspects of binding in the presence of continued hormone secretion are discussed. Nonetheless, the presence of receptors on the cells for hormones secreted by the same cells strongly suggests autoregulation. The apparent low affinity of some of these receptors and the presence of receptors for all three islet cell hormones on all islet cells supports the likelihood of paracrine controls.

Modulation of Glucagon-like Peptide-1 (GLP-1) Potency by Endocannabinoid-like Lipids Represents a Novel Mode of Regulating GLP-1 Receptor Signaling

“…Cell Culture and Transfection of Cell Lines-The RINm5F cell line is derived from a rat islet cell tumor (25,26) and expresses receptors for GLP-1, GIP, and glucagon (27,28). RINm5F cells were seeded at a density of 3 ϫ 10 5 cells/well in 24-well plates and cultured at 37°C and 5% CO 2 in complete RPMI 1640 medium supplemented with 10% (v/v) FBS, 1 mM sodium pyruvate, 14 mM glucose, 1:1000 penicillin/streptomycin, 2 mM glutamine, and 35 mM sodium bicarbonate, pH 7.4, for 16 h. Before transfection, the medium was removed and replaced with 500 l of fresh complete RPMI 1640.…”

“…We probed the potential conformation of GLP-1(7-36) amide based on its susceptibility to trypsin digestion. The two trypsin cleavage products of GLP-1 amide are an inactive GLP-1 (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26) and a partially active GLP-1(7-34) (Fig. 8A) (32).…”

Beta cell chromogranin B is partially segregated in distinct granules and can be released separately from insulin in response to stimulation

“…The peculiar properties of CgB secretion could open a new line of functional research in beta cells, which remains to be developed. [21], RIN-5AH [22] and betaTC3 [23] cells were grown at 37°C, under a 5% CO 2 humidified atmosphere, in RPMI 1640 (INS-1E and betaTC3) or 11 mmol/l glucose-containing DMEM (RIN-5AH) media supplemented with 10% (vol./vol.) fetal clone serum III (Hyclone, Logan, UT, USA), 100 U/ml penicillin per streptomycin and 2 mmol/l ultra-glutamine (Cambrex, Verviers, Belgium).…”

Differential interaction of glimepiride and glibenclamide with the β-cell sulfonylurea receptor I. Binding characteristics

“…RINm5F cells of the insulin-producing cell line, derived from a rat islet cell tumor [22,23], were grown in RPMI-1640 medium containing 10% (v/v) heat-inactivated fetal calf serum, 50 IU/ml penicillin, 0.25 /xg/ml fungizone and 50 ixg/ml streptomycin at 37°C in an atmosphere of humified air/CO 2 (19:1) according to Praz et al [24] with the following modifications: The cells were seeded at a density of (2-4)" 104 cells/ml in 20 ml of medium (75 cm 2 culture flasks). The medium was replaced four times per week (one passage).…”