Insulin-like growth factor I accelerates gastric ulcer healing by stimulating cell proliferation and by inhibiting gastric acid secretion.
BACKGROUND
Given the importance of Insulin-Like Growth Factor I (IGF-I) to intestinal maintenance and the presence of IGF-I in salivary glands, we hypothesized that IGF-I participates in the healing of gastric ulcers. The aim of the study was to determine: 1) whether IGF-I applied locally would support gastric ulcer healing by increasing cell proliferation and 2) the effect of IGF-I on gastric acid secretion.


METHODS
Gastric ulcers were induced with a cryoprobe. Immediately thereafter, IGF-I (0.4, 4.0 and 40 microg) or vehicle was infiltrated perifocally. In another group, animals received a daily dose of 40 micromol omeprazole subcutaneously. Ulcer healing was evaluated by ulcer size and histological examination at 7 days. Pentagastrin-stimulated gastric acid secretion was evaluated in conscious rats with gastric fistula, after IGF-I (400 microg) had been injected intravenously.


RESULTS
IGF-I significantly reduced ulcer size, but only at low doses (0.4 microg/kg body weight (BW), P = 0.008; 4 microg/kg BW, P = 0.001). This effect was similar to omeprazole treatment. Histological examination after IGF-I administration showed increased cell proliferation, increased IGF-I content and down-regulated IGF-I receptors. The secretory studies demonstrated a significant decrease in gastric acid secretion 30 min after IGF-I bolus injection (IGF-I: 53 +/- 11 microEq; vehicle: 116 +/- 5 microEq; P=0.001), which lasted for more than 1 h.


CONCLUSIONS
IGF-I stimulates gastric ulcer healing, stimulating cell proliferation and inhibiting gastric acid secretion.
Coerper
S
S
Dept. of General Surgery, University of Tübingen, Germany. Stephan.Coerper@t-Online.de
Wolf
S
S
von Kiparski
S
S
Thomas
S
S
Zittel
T T
TT
Ranke
M B
MB
Hunt
T K
TK
Becker
H D
HD
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013276:Stomach Ulcer / Q000188:drug therapy* / Q000503:physiopathology; D014945:Wound Healing / Q000187:drug effects
D007334:Insulin-Like Growth Factor I