Recent autoradiographic studies demonstrated that Bcells concentrate 1,25 (OH)2 D3 in their nuclei, suggesting a genomic action on B-cell function. This study was undertaken to investigate the effects of 1,25 (OH)2 D3 on insulin secretion in vitamin D-deficient rats. Mature vitamin D-deficient rats were injected with 1,25 (OH)2 D3 or the ethanol-isotonic saline vehicle. Administration of 1,25 (OH)2 D3 to 10 rats resulted in a 17 μu/ml (113%) increase in insulin levels and 0.9 mg/dl (16%) increase in plasma calcium. No changes were found in insulin or calcium levels in 5 control rats given vehicle alone. A group of vitamin D-deficient rats with plasma calcium levels of 5.4 ± 0.1 mg/dl had insulin levels that were the same as those observed in a group of vitamin D-deficient rats with plasma calcium levels of 6.3 ± 0.1 mg/dl. The difference in calcium levels between these two groups is similar to the increase in plasma calcium found after 1,25 (OH)2 D3 administration. The results of these studies indicate that 1,25 (OH)2 D3 action on pancreatic B-cells affects insulin secretion. Since insulin increases synthesis of 1,25 (OH)2 D3, the existence of a feedback loop between B-cells and kidney proximal tubule cells is suggested.
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Original contribution| May 01 1981
Effect of 1,25 Dihydroxyvitamin D3 on Insulin Secretion
Samuel A Clark;
Walter E Stumpf;
Address reprint requests to Samuel A. Clark, Department of Anatomy, 111 Swing Building, University of North Carolina, Chapel Hill, North Carolina 27514.
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Samuel A Clark, Walter E Stumpf, Madhabananda Sar; Effect of 1,25 Dihydroxyvitamin D3 on Insulin Secretion. Diabetes 1 May 1981; 30 (5): 382–386. https://doi.org/10.2337/diab.30.5.382
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