Title: Actively Synthesizing<i>β</i>-Cells Secrete Preferentially after Glucose Stimulation*
Abstract: To establish whether the heterogeneous secretion of glucose-stimulated β-cells correlates with a different biosynthetic activity, we have studied the secretion and biosynthesis of the very same β-cells by combining a hemolytic plaque assay with autoradiography. After a 10-min incubation in 2.8 mm glucose, 52 ± 2% of dispersed rat β-cells incorporated [3H] leucine into newly synthesized proteins, as revealed by autoradiographic labeling. When the incubation was performed in 16.7 mm glucose, larger (P < 0.02) proportions (92 ± 4%) of plaqueforming, i.e. insulin-secreting, and nonplaque-forming β-cells (74 ± 4%) were autoradiographically labeled. Labeled and unlabeled β-cells were stimulated to secrete insulin during a 30- min incubation in 16.7 mm glucose, as revealed by the larger (P < 0.001) formation of hemolytic plaques. Under these conditions, autoradiographically labeled β-cells were recruited preferentially (P < 0.01) and secreted more (P < 0.04) than unlabeled β-cells. Analogous observations were made with β-cell pairs. Under glucose stimulation, pairs comprising two autoradiographically labeled β-cells secreted more (P < 0.004) than pairs comprising one or no labeled β-cells. The data indicate that under glucose stimulation, 1) secreting and nonsecreting β-cells increase protein biosynthesis; 2) biosynthetically active and inactive β-cells increase insulin secretion; 3) β-cells synthesizing new proteins release insulin preferentially; and 4) contact decreases the biosynthetic and secretory heterogeneity of β-cells. (Endocrinology129: 3157–3166, 1991)
Publication Year: 1991
Publication Date: 1991-12-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 80
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