AJP - Renal Physiology, Vol 267, Issue 2 325-F330, Copyright © 1994 by American Physiological Society
Distribution of kallikrein-binding protein mRNA in kidneys and difference between SHR and WKY rats
T. Yang, Y. Terada, H. Nonoguchi, M. Tsujino, K. Tomita and F. Marumo
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
We investigated kallikrein-binding protein (KBP) mRNA distribution in the
kidney of Sprague-Dawley (SD) rats, spontaneously hypertensive rats (SHR),
and Wistar-Kyoto strain (WKY) rats. Northern blot analysis revealed that
KBP mRNA was located mainly in the medulla and with lower amounts in SHR
than in WKY rats. KBP mRNA in microdissected nephron segments was detected
by reverse transcription and polymerase chain reaction (RT-PCR) followed by
Southern blot analysis. In SD rats, the most abundant signals were
consistently found in inner medullary collecting duct (IMCD), with small
amounts in outer medullary collecting duct, proximal convoluted tubule, and
glomerulus. No signals were found in connecting tubule and cortical
collecting duct. The nephron distribution of KBP mRNA was similar in WKY
and SD rats. Only a small amount of signal was found, however, in IMCD of
SHR. In conclusion, 1) KBP mRNA was predominantly distributed in the
medullary segments of the distal nephron, downstream from the known
kallikrein activity site in the collecting duct, and 2) KBP mRNA expression
was significantly decreased in the kidney of SHR.
