AJP - Renal Physiology, Vol 260, Issue 5 626-F634, Copyright © 1991 by American Physiological Society
Glomerular B2-kinin-binding sites in two-kidney, one-clip hypertensive rats
C. Emond, J. L. Bascands, J. Rakotoarivony, F. Praddaude, G. Bompart, C. Pecher, J. L. Ader and J. P. Girolami
Institut National de la Sante et de la Recherche Medicale, Faculte de Medecine Rangueil, Toulouse, France.
To extend our recent observations of the possible downregulation of
glomerular B2-kinin-binding sites, we investigated density (Bmax) of
bradykinin (BK)-binding sites in glomerular membranes of both the clipped
(C) and nonclipped (NC) kidneys of two-kidney, one-clip (2K-1C) Goldblatt
hypertensive rats, in relation to tissue kallikrein activity and glomerular
three-dimensional structure. Compared with the Bmax of sham-operated (SO)
kidney (31.8 +/- 7 fmol/mg protein), a significant increase in Bmax was
observed in glomeruli of both kidneys in hypertensive rats, the Bmax being
higher in glomeruli of NC than in C kidneys (98 +/- 11 vs. 59 +/- 12
fmol/mg protein). NC kidney compensatory hypertrophy was expressed by an
increase in glomerular diameter, surface area, and volume. When expressed
per unit of area or volume, Bmax in NC kidneys remained significantly
higher than in both C and SO kidneys. Increased Bmax in both kidneys of
2K-1C rats was associated with a decreased intrarenal level of kallikrein.
We also examined prostaglandin (PG) E2 release by isolated glomeruli from
SO, C, and NC kidneys as a possible biological effect induced by BK.
Whereas C kidney released more PGE2 than NC kidney under basal conditions,
addition of BK (10 nM) induced greater PGE2 production in NC kidney
consistent with the difference in Bmax between C and NC kidneys. These
results suggest a possible downregulation of glomerular B2-binding sites by
bradykinin, which may explain the difference between SO and C
kidneys.(ABSTRACT TRUNCATED AT 250 WORDS)
