The effect of epidermal growth factor and IGF-I infusion on hepatic and renal expression of the IGF-system in adult female rats
Systemic administration of epidermal growth factor (EGF) in neonatal rats results in reduced body weight gain and decreased circulating levels of IGF-I, suggesting its involvement in EGF-induced growth retardation. We investigated the effect of EGF and/or IGF-I administration for 7 days on circulating IGF-I and IGFBP levels and hepatic and renal IGF-system mRNA expression profiles in adult female rats. EGF administration (30 microg/rat/day) did not influence body weight, liver or kidney weight. In contrast, IGF-I (400 microg/rat/day) and EGF/IGF-I administration increased both body weight and kidney weight. Also, serum IGF-I and the 30 kDa IGFBPs (IGFBP-1 and -2) were significantly increased in these groups. Serum IGFBP-3 levels increased in the IGF-I group along with increased hepatic IGFBP-1 and -3 mRNA levels. In contrast, in the EGF administration group serum IGFBP-3 levels were significantly decreased; however, the mRNA levels remained unchanged. In the EGF/IGF-I administration group, serum IGF-I and IGFBP-3 levels were significantly lowered when compared with the IGF-I administration group. This was in contrast to the effect on kidney weight increase that was identical for the IGF-I and EGF/IGF-I groups. The decrease in serum IGFBP-3 was not reflected at the hepatic IGFBP-3 mRNA level. IGFBP-3 expression might be regulated at a post-transcriptional level although EGF induced IGFBP-3 proteolysis could not be demonstrated in vitro. We conclude that EGF administration reduced serum IGFBP-3 whereas IGF-I administration increased the level of IGFBP-3 and IGF-I and resulted in an increased body and kidney weight in adult female rats.
|Keywords||Animals, Body Weight/drug effects, Epidermal Growth Factor/*pharmacology, Female, Insulin-Like Growth Factor Binding Proteins/blood/*drug effects, Insulin-Like Growth Factor I/*pharmacology, Kidney/*drug effects/metabolism, Liver/*drug effects/metabolism, RNA, Messenger/*drug effects/metabolism, Rats, Rats, Wistar, Research Support, Non-U.S. Gov't|
van Neck, J.W., Berghout, E.M., Vinter-Jensen, L., Groffen, C.A.H., Cingel-Ristic, V., Dits, N.F., … Flyvbjerg, A.. (2000). The effect of epidermal growth factor and IGF-I infusion on hepatic and renal expression of the IGF-system in adult female rats. Journal of Endocrinology. Retrieved from http://hdl.handle.net/1765/9305