Human proximal tubular epithelial cells express somatostatin:
regulation by growth factors and camp.
Turman, Martin A., and Courtney A. Apple.
Department of Pediatrics, The Ohio State University and the Wexner
Institute for Pediatric Research, Children's Hospital, Columbus,
Ohio, 43205
APStracts 5:0048F, 1998.
Somatostatin modulates several renal tubular cell functions, including
gluconeogenesis and proliferation. In this study we demonstrate that
cultured human proximal tubular epithelial cells (PTEC) express
somatostatin. We also demonstrate positive and negative regulation of
PTEC somatostatin production. We found that PTEC derived from 14
different human donors consistently expressed somatostatin mRNA
and/or peptide as detected by reverse transcription and polymerase
chain reaction (RT-PCR) and enzyme-linked immunoassay. Furthermore,
Northern blot analysis revealed that PTEC express the same size mRNA
transcript (750 nucleotides) as human thyroid carcinoma (TT) cells.
The PTEC mitogens, epidermal growth factor (EGF) and hydrocortisone,
inhibit PTEC somatostatin secretion, whereas forskolin (a direct
stimulator of adenylate cyclase) and fetal calf serum stimulate
secretion. These findings raise the possibility that renal-derived
somatostatin modulates tubular cell function in an
autocrine/paracrine manner. Manipulation of this pathway may lead to
novel methods to alter tubular cell proliferation and function in
vivo.
Received 29 September 1997; accepted in final form 19 February
1998.
APS Manuscript Number F315-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 9 March 1998