[Inhibition of growth hormone in insulin-dependent diabetics after oral administration of pirenzepine. Fluorophotometric study of the vitreous body].

The purpose of our study was to quantify the blood-retinal barrier permeability in five patients with insulin-dependent diabetic (mean age 14.96 +/- 2.45 years) without retinopathy, after six month with oral pirenzepine, a growth hormone inhibitor. Blood-retinal barrier permeability was determined by vitreous fluorophotometry before and after treatment with a nocturnal oral dose of pirenzepine (0.6 mg/kg the first month and 1 mg/kg the following five months). We found a significant diminution (p < 0.05) in growth hormone levels (10.48 +/- 4.94 ng/ml before treatment and 4.35 +/- 2.53 ng/ml after treatment), nevertheless, no changes in the blood-retinal barrier permeability values were observed (4.84 +/- 2.08 x 10(-6) min-1 before treatment and 4.53 +/- 2.54 x 10(-6) min-1 after treatment). We found no modifications in the levels of somatomedin C or HbA1c either. It can be concluded that oral pirenzepine used at this dose for six months, in spite of a significant decrease in growth hormone secretion, does not decrease the permeability of the blood-retinal barrier.