Dietary and Hormonal Factors Affecting the mRNA Level of IGF-I in Rat Liver in vivo and in Primary Cultures of Rat Hepatocytes
Insulin-like growth factor I (IGF-I, or somatomedin C) is a hormone, which has been shown to be important in the anabolism of dietary proteins into body proteins (Spencer, 1983). Plasma IGF-I level is affected by many nutritional factors including energy intake (Isley et al., 1983), dietary protein level (Prewitt et al., 1982) and nutritional quality of dietary proteins (Bolze et al., 1985; Takahashi et al., 1988). IGF-I probably works in coordination with insulin but in a different manner in the anabolism of dietary proteins, because, different from insulin, plasma immunoreactive IGF-I level does not increase significantly after a meal and is primarily affected by the dietary composition of the nutrients. Another evidence of the difference in the response of insulin and IGF-I is the manner of response of these two hormones to streptozotocin administration. Imraunoreactive insulin level decreases very quickly after streptozotocin administration whereas IGF-I level is affected gradually, presumably as a secondary effect of insulin deficiency (Takahashi et al., 1988).
KeywordsGrowth Hormone Dietary Protein Dietary Protein Level Streptozotocin Administration
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