Dissociation between insulin secretion and DNA synthesis in cultured pancreatic islets
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Dissociation between insulin secretion and DNA synthesis in cultured pancreatic islets. / Nielsen, Jens Høiriis.
I: Biomedica Biochimica Acta, Bind 44, Nr. 1, 1985, s. 161-6.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - Dissociation between insulin secretion and DNA synthesis in cultured pancreatic islets
AU - Nielsen, Jens Høiriis
PY - 1985
Y1 - 1985
N2 - Glucose has been suggested to be the most important stimulus for beta cell replication in vivo and in vitro. In order to study the relationship between insulin secretion and DNA synthesis, newborn rat islets were cultured in the presence of different concentrations of glucose, theophylline and 3-isobutyl-1-methylxanthine (IBMX). DNA synthesis was evaluated by the incorporation of [3H]thymidine (3H-Tdr) into islet DNA, and the release of insulin and the content of insulin and DNA in the islets were determined. No difference in 3H-Tdr incorporation was observed after 24 h culture in 5.5, 11 and 22 mM glucose in spite of a dose dependent increase in insulin release. 5 mM theophylline potentiated the glucose induced insulin release but lowered both 3H-Tdr synthesis and insulin content in the islets. In contrast, 0.05 mM IBMX induced a significant stimulation of both insulin release and 3H-Tdr incorporation. However, long-term exposure to IBMX did not result in increased DNA content of the islets. Inhibition of the DNA synthesis by 5 mM hydroxyurea resulted in a marked reduction in DNA content of the islets but no decrease in either insulin release or insulin content when expressed per ng DNA. These results indicate that insulin secretion and DNA synthesis can be dissociated and may suggest participation of factors other than glucose in the control of beta cell replication.
AB - Glucose has been suggested to be the most important stimulus for beta cell replication in vivo and in vitro. In order to study the relationship between insulin secretion and DNA synthesis, newborn rat islets were cultured in the presence of different concentrations of glucose, theophylline and 3-isobutyl-1-methylxanthine (IBMX). DNA synthesis was evaluated by the incorporation of [3H]thymidine (3H-Tdr) into islet DNA, and the release of insulin and the content of insulin and DNA in the islets were determined. No difference in 3H-Tdr incorporation was observed after 24 h culture in 5.5, 11 and 22 mM glucose in spite of a dose dependent increase in insulin release. 5 mM theophylline potentiated the glucose induced insulin release but lowered both 3H-Tdr synthesis and insulin content in the islets. In contrast, 0.05 mM IBMX induced a significant stimulation of both insulin release and 3H-Tdr incorporation. However, long-term exposure to IBMX did not result in increased DNA content of the islets. Inhibition of the DNA synthesis by 5 mM hydroxyurea resulted in a marked reduction in DNA content of the islets but no decrease in either insulin release or insulin content when expressed per ng DNA. These results indicate that insulin secretion and DNA synthesis can be dissociated and may suggest participation of factors other than glucose in the control of beta cell replication.
KW - Animals
KW - Animals, Newborn
KW - Cells, Cultured
KW - DNA
KW - Insulin
KW - Islets of Langerhans
KW - Rats
M3 - Journal article
C2 - 3888206
VL - 44
SP - 161
EP - 166
JO - Biomedica Biochimica Acta
JF - Biomedica Biochimica Acta
SN - 0232-766X
IS - 1
ER -
ID: 47975197