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1,25-Dihydroxyvitamin D/sub 3/ target cells in immature pancreatic islets

Journal Article · · Am. J. Physiol.; (United States)
OSTI ID:6143058

Target cells of 1,25-dihydroxyvitamin D/sub 3/ were identified by autoradiography in islets from rats of different ages. Nuclei of pancreatic islet cells selectively concentrated 1,25-(/sup 3/H)dihydroxyvitamin D/sub 3/ but not 25-(/sup 3/H)hydroxyvitamin D/sub 3/ or 24,25-(/sup 3/H)dihydroxyvitamin D/sub 3/. Developmental studies of pancreatic islets indicated that target cells, as revealed by significant nuclear concentration of 1,25-(/sup 3/H)dihydroxyvitamin D/sub 3/, are present in islet cells of fetal rats. The percentage of islet cells that concentrated 1,25-(/sup 3/H)dihydroxyvitamin D/sub 3/ increased from 10 to 15% in the fetus to 60% at 1 day of age. Immunocytochemical staining indicated that insulin-containing cells but not glucagon or somatostatin cells concentrated 1,25-(/sup 3/H)dihydroxyvitamin D/sub 3/. Peak uptake of 1,25(/sup 3/H) dihydroxyvitamin D/sub 3/ was calculated to be 400 pmol/mg DNA, with no significant difference in nuclear accumulation between islets cells from neonatal and adult rats or between islets in vivo and isolated islets in vitro. The results of these studies indicate that (1) 1,25-(/sup 3/H)dihydroxyvitamin D/sub 3/ target cells are present in islets before pancreatic ..beta..-cells are morphologically or functionally mature; (2) islet ..beta..-cells concentrate 1,25-dihydroxyvitamin D/sub 3/, but not 25-hydroxyvitamin D/sub 3/ or 24,25-dihydroxyvitamin D/sub 3/. The authors conclude that only the 1,25-dihydroxyvitamin D/sub 3/ metabolite of vitamin D is accumulated by nuclei of developing and mature ..beta..-cells and suggest that 1,25-dihydroxyvitamin D/sub 3/ plays a role in the maturation of islet ..beta..-cells.

Research Organization:
Univ. of North Carolina, Chapel Hill (USA)
OSTI ID:
6143058
Journal Information:
Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 253:1; ISSN AJPHA
Country of Publication:
United States
Language:
English