Compensatory renal growth in uninephrectomized immature rats: proliferative activity and epidermal growth factor.
Compensatory response to uninephrectomy in immature animals is stronger compared with that in adult ones and the response is due mainly to renal cell proliferation. The present study explored to show the growth pattern of the remaining kidney immediately after uninephrectomy in immature rats with special reference to proliferating activity and epidermal growth factor (EGF). Immunolocalizations of proliferating cell nuclear antigen (PCNA) and EGF in immature rat kidney were examined during the first three days after uninephrectomy. Semi-quantitative analysis of the expression of preproEGF mRNA was performed. One day after the operation, the PCNA positive cell ratios in the glomeruli and the proximal tubules were significantly higher in unilaterally nephrectomized (UNx) rats than in sham-operated (Sham) rats. In UNx and Sham rats, the proximal and distal tubular cells showed positive reactions to EGF antibody. The positive reaction of proximal tubules to EGF antibody was weaker in UNx than in Sham rats 1 day after the operation, while the degree of reactivity was not different between UNx and Sham rats 3 days after the operation. The level of expression of preproEGF mRNA in the kidney was significantly lower in UNx than in Sham rats 1 day after the operation. These results indicate that unilateral nephrectomy in immature rats causes increased proliferative activity and decreased expression of EGF in the remaining kidney during the early period of compensatory renal growth.
Department of Integrated Structural Biosciences, Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan. okada@vet.osakafu-u.ac.jp
Toshiya
T
Okada
Mika
M
Omoto-Kitao
Masafumi
M
Mukamoto
Jun
J
Nakamura
Masaki
M
Mino
Tomohiro
T
Kondo
Ai
A
Takeshita
Ken Takeshi
KT
Kusakabe
Keiko
K
Kato
D000199:Actins / Q000235:genetics; D000818:Animals; D017931:DNA Primers; D004815:Epidermal Growth Factor / Q000235:genetics* / Q000502:physiology; D007668:Kidney / Q000166:cytology / Q000254:growth & development*; D007678:Kidney Glomerulus / Q000166:cytology; D007684:Kidney Tubules / Q000166:cytology; D009392:Nephrectomy / Q000662:veterinary*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000199:Actins; D017931:DNA Primers; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D004815:Epidermal Growth Factor