Expression of the insulin-like growth factor system in postpneumonectomy lung growth.
The insulin-like growth factors (IGF-I and IGF-II) may play an important role in postpneumonectomy compensatory lung growth by translating hormonal inputs and mechanical forces into cellular proliferation signals. We examined the mRNA abundance of IGF-I, IGF-II, and IGF binding proteins (IGFBPs) in lungs of rats on postoperative days 1, 2, 3, 5, and 7 following left pneumonectomy (PNX) or shamoperation (SC) and in normal animals (CON). There was no difference in the abundance of lung IGF-I mRNA (measured by Northern analysis) or serum IGF-I (measured by radioimmunoassay (RIA)) between SC and PNX animals. IGF-II mRNA abundance was initially decreased following PNX (73% decrease compared to SC animals on day 1, p < .05) and then rose to approach SC group values on subsequent days. Transcripts for IGFBP-2, -3, -4, -5, and -6 were decreased in both the SC and PNX groups compared to CON animals on the day following pneumonectomy, then rose back to baseline by postoperative day 2-3. Tissue IGFBPs, measured by ligand blot analyses, were not different in either the SC or PNX groups. In contrast, all serum IGFBP bands were increased on postoperative day 1 following either sham or PNX surgery. In addition, serum IGFBP-4 was increased in PNX animals compared to the SC group on days 1 and 2 (increase of 38% and 78%, respectively, p < .05). We conclude that the changes observed in lung IGF and IGFBP expression following pneumonectomy do not represent major.
Price
W A
WA
Department of Pediatrics, University of North Carolina at Chapel Hill, USA. waprice.pedslan@mhs.unc.edu
Moats-Staats
B M
BM
Sekhon
H S
HS
Chrzanowska
B L
BL
Thurlbeck
W M
WM
Stiles
A D
AD
D000818:Animals; D015152:Blotting, Northern; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis* / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis* / Q000378:metabolism; D008168:Lung / Q000033:anatomy & histology / Q000378:metabolism* / Q000502:physiology*; D008297:Male; D009929:Organ Size / Q000502:physiology; D011013:Pneumonectomy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000502:physiology*
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II