J. Shohat et al., SERUM AND RENAL IGF-I LEVELS AFTER UNINEPHRECTOMY IN THE RAT, Scandinavian journal of clinical & laboratory investigation, 57(2), 1997, pp. 167-173
The hypertrophy of the remaining kidney following uninephrectomy (UNx)
has been related to an increase in renal insulin growth factor-I (IGF
-I) content. However, while the increase in renal IGF-I lasts for only
days after UNx, renal hypertrophy continues for months. In the presen
t study we investigated whether IGF-I also plays a role in the late po
st uninephrectomy growth of the remaining kidney. Renal IGF-I in the r
emnant kidney was greater than that of control kidneys (78.3 +/- 17.3
vs 56.0 +/- 14.0 pmol g(-1); p < 0.05)3 days after UNx, tended to rema
in higher 30 days after UNx (83.8 +/- 23.6 vs 57.3 +/- 14.5 pmol g(-1)
; p = 0.07), but was similar to that of the control kidney when examin
ed 60 days after UNx (66.6 +/- 15.6 vs. 70.4 +/- 6.7 pmol g(-1)). Seru
m IGF-I in uninephrectomized rats was similar to that of controls 3 da
ys after UNx, started to increase above the control level at day 10 af
ter UNx and remained higher 30 and 60 days after UNx (75.9 +/- 6.9 vs.
48.7 +/- 7.3 nmol l(-1) at 30 days, and 81.2 +/- 13.7 vs 52.9 +/- 11.
0 nnol l(-1) at day 60, p<0.05 for both). The kidney weight of unineph
rectomized rats was higher by 21% than that of controls 3 days after U
Nx, by 45% 30 days after UNx and by 63% 60 days after UNx (p<0.05 for
all three observations). At the end of the study, the glomerular volum
e of uninephrectomized rats was higher by 36% than that of the control
s (p<0.05). We suggest that in the rat, while the initial post unineph
rectomy hypertrophy of the remnant kidney is associated with and most
probably mediated by an increase in renal IGF-I, the hypertrophy;hat p
ersists in later post UNx periods is associated with and may be mediat
ed by an increase in serum IGF-I.