Modulation of Insulin-like Growth Factor-I Production of Cultured Retinal Vascular Endothelial Cells by Oxygen, Glucose and Growth Hormone

Abstract

Purpose: To evaluate the interaction of oxygen, glucose, and growth hormone (GH) on insulin-like growth factor-I (IGF-I) production of cultured bovine retinal vascular endothelial cells. Methods: Confluent cultures of bovine retinal vascular endothelial cells were incubated under 3% or 20% oxygen in Dulbecco's modified Eagle's medium (containing 1 g/L or 4.5 g/L glucose), with or without the addition of 10 ng/mL GH. After incubation times of 0, 24, 48, and 72 hours, IGF-I was measured in the supernatant, and cells were counted. Results: Highest levels of IGF-I were reached after 72 hours with 4.5 g/L glucose and 10 ng/mL GH under 3% O 2. All IGF-I levels found in 3% O 2 samples were significantly higher than those found in 20% O 2 samples. No statistical significance was found regarding glucose concentration or GH supplement. Conclusions: Oxygen turned out to be the sole modulating factor for IGF-I production of cultured retinal vascular endothelial cells.