IGF-binding protein-2 is induced during development of urinary bladder hypertrophy in the diabetic rat.
Because the locally produced insulin-like growth factor-binding proteins (IGFBP) may influence bladder hypertrophy, either directly or by their interaction with insulin-like growth factor I (IGF-I), we studied the IGF system during the development of urinary bladder hypertrophy in rats with streptozotocin-induced diabetes. Messenger RNA for IGF-I, IGFBP-2, and IGFBP-4 was determined by solution hybridization. The bladder wet weight was elevated after 7 days. DNA synthesis was increased and peaked at 2 days, whereas DNA content per bladder wet weight was decreased by 7 days. The IGF-I mRNA did not change during the first 7 days and then decreased, and IGFBP-4 mRNA was increased transiently on day 7. On the other hand, IGFBP-2 mRNA was significantly increased after 1 day (2-fold), peaked by 7 days (6.4-fold), and then declined to approximately 50% above control at the end of experiment. This was associated with an increased IGFBP-2 protein content. Our results suggest that both stretching of the bladder due to diuresis and the diabetic state contribute to changes of the IGF system in the hypertrophying bladder.
Chen
Y
Y
Department of Cellbiology, Faculty of Health Sciences, University of Linköping and University Hospital, Sweden.
Gustafsson
B
B
Arnqvist
H J
HJ
D000818:Animals; D004247:DNA / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000473:pathology*; D006984:Hypertrophy; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics / Q000378:metabolism*; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D001743:Urinary Bladder / Q000378:metabolism* / Q000473:pathology*
D018971:Insulin-Like Growth Factor Binding Protein 2; D018974:Insulin-Like Growth Factor Binding Protein 4; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D004247:DNA