Renal content and output of epidermal growth factor in long-term adrenergic agonist-treated rats

This study investigates the renal and urinary levels of epidermal growth fa ctor (EGF) in rats under long-term treatment with alpha- or beta-adrenergic agonists. Urine samples were obtained on days 7, 14 and 21, and renal tiss ue samples on day 21. EGF was quantified by ELISA and tissue sections were used for immunohistochemistry and in situ hybridization. Fractional kidney weight was increased in the alpha-adrenergic agonist-treated group by 35% w hen compared with controls. Histological examination of the kidney revealed well-defined wedge-shaped areas of tubular dilatations and luminal amorpho us material in the distal tubules. Concomitantly, reduced levels of EGF and EGF mRNA were observed, and also the urinary levels of EGF were reduced. T ogether, these observations indicate alpha-adrenergic treatment to affect t he distal tubules. Treatment with the beta-adrenegic agonist did not change fractional kidney weight, but initially the urinary excretion of EGF was r educed. The data add further evidence to the suggestion that activity of th e sympathetic nervous system influences renal homeostasis of EGF, either di rectly or indirectly through renal histopathological changes. (C) 2000 Else vier Science BSI. All rights reserved.