Increased gene expression of insulin-like growth factor-i receptor in experimental diabetic rat glomeruli.
Renal hypertrophy is a characteristic and early manifestation of diabetes in humans and experimental animals. We examined the precise distribution of insulin-like growth factor-I (IGF-I) mRNA and IGF-I receptor mRNA in the experimental diabetic rat kidney using a nonradioactive in situ hybridization technique. No significant difference in the distribution of IGF-I mRNA was found between the diabetic and control rats. IGF-I mRNA-positive cells were found in the collecting ducts and in scattered single cells in the distal tubules. The number of IGF-I mRNA-positive cells was very low in the glomeruli. Expression of IGF-I receptor mRNA was rarely seen in the glomeruli of control rats. IGF-I receptor mRNA was detected after induction of diabetes in glomerular mesangial, visceral epithelial, and parietal epithelial cells. The number of IGF-I receptor mRNA-positive cells in a glomerulus increased significantly, peaking at 4 weeks as compared with the control rats. Overexpression of IGF-I receptor in glomerular cells, especially mesangial and visceral epithelial cells, may contribute to glomerular hypertrophy in diabetic nephropathy.
Sugimoto
H
H
Third Department of Internal Medicine, Okayama University Medical School, Japan.
Shikata
K
K
Makino
H
H
Ota
K
K
Ota
Z
Z
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D003928:Diabetic Nephropathies / Q000378:metabolism* / Q000473:pathology; D017403:In Situ Hybridization; D007678:Kidney Glomerulus / Q000378:metabolism* / Q000473:pathology; D008297:Male; D015345:Oligonucleotide Probes; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis* / Q000235:genetics*
D001786:Blood Glucose; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D017526:Receptor, IGF Type 1