Demonstration of Fibroblast Growth Factor Receptor-1 in Rat Adrenal Gland as Revealed by Reverse Transcription-polymerase Chain Reaction and Immunohistochemistry

Abstract

Recent studies have shown that FGF-1 (aFGF) and FGF-2 (bFGF) are expressed in the adrenal glands. In order to understand the roles of FGFs in the adrenal gland, we investigated the expression of the fibroblast growth factor receptor-1 (FGFR1) in rat adrenal gland using reverse transcription-polymerase chain reaction (RT-PCR) method, Western blot and immunohistochemistry. RT-PCR experiment using a primer set to amplify the acidic region of FGFR1 gave two bands of about 426 bp and 160 bp in both the adrenal cortex and medulla. The sizes of the large and small PCR products corresponded well to the three IgG-like domain (long form) and two IgG-like domain (short, or secreted form) FGFR1, respectively. Western blotting analysis using an antibody capable of detecting the acidic region of FGFR1, gave two bands in the adrenal gland with molecular weights of about 130 kDa and 75 kDa, corresponding to the long and the secreted form of FGFR1, respectively. Immunohistochemical study using the antibody demonstrated that FGFR1-positive cells were distributed mainly in the zona glomerulosa of the adrenal cortex and medulla. A few positive cells were scattered in the zona fasciculata and reticularis. In the adrenal medulla, almost all cells were positive for FGFR1. Double immunostaining revealed that FGFR1 colocalized with tyrosine hydroxylase-immunoreactive catecholamine cells in the adrenal medulla.