INSULIN REGULATES INSULIN-LIKE GROWTH FACTOR-I MESSENGER-RNA IN RAT HEPATOCYTES
INSULIN REGULATES INSULIN-LIKE GROWTH FACTOR-I MESSENGER-RNA IN RAT HEPATOCYTES
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DOI:
10.1152/ajpendo.1991.260.6.e846
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发表时间:
1991-06-01
影响因子:
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通讯作者:
FROESCH, ER
中科院分区:
文献类型:
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作者:
BONISCHNETZLER, M;SCHMID, C;FROESCH, ER
To evaluate the regulatory role of growth hormone (GH) and insulin on insulin-like growth factor I (IGF-I) mRNA levels, we employed primary rat hepatocytes. Cells were incubated for 16 h with 10 nM insulin, 10 nM GH, or a combination thereof, and IGF-I mRNA levels were analyzed by Northern blotting. Insulin results in 2.5-fold and GH in 3.8-fold higher IGF-I mRNA levels than hormone-free controls, and a combination of insulin and GH had an additive effect (6.7-fold). The effect of 10 nM insulin was constant at variable GH concentrations. Therefore, GH and insulin affect IGF-I mRNA levels independently of each other. The half-maximal effective dose of insulin was 4.7 x 10(-10) M, and, in kinetic experiments, insulin was effective within 2 h. These findings demonstrate that insulin modulates hepatic IGF-I production by a direct regulation of the transcript levels of IGF-I.