뇌하수체 제거 흰쥐에서 보상성신비대과정 중 외인성 IGF-Ⅰ투여가 내인성 IGF-Ⅰ의 생산, 신기능 및 신비대의 성격에 미치는 영향
Other Titles
Effects of Exogenous IGF-Ⅰ on Endogenous IGF-Ⅰ Production, Function and Hyperplasia / Hypertrophy of Kidney during Compensatory Renal Growth in Hypophysectomized Rats
Authors
한상원 ; 조철규 ; 민병석
Citation
Korean Journal of Urology (대한비뇨기과학회지), Vol.40(6) : 749-755, 1999
Purpose: Compensatory renal hypertrophy(CRH) after loss of considerable renal volume
is essential process for recovery and maintenance of renal function, but on the other
hand CRH induces glomerulosclerosis, eventually renal failure. Recently, the considerable
studies reveal that insulin-like growth factor-Ⅰ(IGF-Ⅰ) is an important molecule
relating to renal hypertrophy. This study investigates the possibility of IGF-Ⅰ as a
therapeutic agent, it should be proved whether External IGF-Ⅰ affects renal function
and glomerulosclerosis or does not affect in devoid state of growth hormone(GH) effect.
Materials and Methods: 100-150g Sprague-Dawley male rats were hypophysectomized
by transpharyngeal approach and hypophysectomy were confirmed by daily monitoring
of body weight for 3 weeks. The left kidney were removed in the rats of UNX group
(uninephrectomy) and UNX+IGF-Ⅰ group(IGF-Ⅰ treated after uninephrectomy), and
sham operation were done in the other rats of control group and IGF-Ⅰ group(IGF-Ⅰ
treated). Recombinant IGF-Ⅰ were administered via Alzet osmotic minipump for 5 days
in rats of IGF-Ⅰ group and UNX+IGF-Ⅰ group. At the 5th day after uninephrectomy,
the glomerular filtration rate(GFR) and the effective renal plasma flow(ERPF) were
investigated by measuring recovery of 99mTc-DTPA and
125I-hippurate, and then the rats were sacrificed and the kidneys were
removed. The wet kidney weights were measured in removed kidneys, renal IGF-Ⅰ
concentrations were measured by RIA, andcellularproliferationwereevaluated by
flow-cytometry.
Results: 1. The wet kidney weight per body weight significantly increased after
uninephrectomy, and had not been affected by IGF-Ⅰ treatment regardless of
uninephrectomy. 2. Renal IGF-Ⅰ tended to increase after uninephrectomy, and
significantly increased with IGF-Ⅰ treatment in both IGF-Ⅰ and UNX+IGF-Ⅰ. The
level of renal IGF-Ⅰ of UNX+IGF-Ⅰ group was significantly higher than that of IGF-
Ⅰ group. 3. Total GFR tended to decreased after uninephrectomy and were significantly
increased by IGF-Ⅰ treatment regardless of uninephrectomy. 4. The GFR per g wet
kidney weight significantly increased after uninephrectomy, and were significantly
increased by IGF-Ⅰ treatment regardless of uninephrectomy. 5. Total ERPF were not
significantly changed after uninephrectomy and significantly increased by IGF-Ⅰ
treatment in sham operation group but did not changed by IGF-Ⅰ treatment in
uninephrectomy group. 6. The ERPF per g wet weight significantly increased after
uninephrectomy, and significantly increased by IGF-Ⅰ treatment in sham operation
group but did not changed by IGF-Ⅰ treatment In uninephrectomy group. 7. The mean
% of S1 phase cells were 33.6% in UNX+IGF-Ⅰ group, 23.5% in IGF-Ⅰ group, 19.96%
in UNX group, and 10.4% in control group. The mean % of G2+M phase cells were
2.5% in UNX+IGF-Ⅰ group, l.95% in IGF-Ⅰ group, 1.73% in UNX group, and 1.2% in
control group.
Conclusions: GH non-dependent IGF-Ⅰ participate in CRH, and only IGF-Ⅰ without
GH increases renal function. IGF-Ⅰ treatment during CRH might increase GFR by
changing glomerular efferent arteriol of filtration fraction.