Effect of growth hormone suppression on glycemic control and other hormonal changes in diabetic retinopathy

ABSTRACT

The study was carried out on ten insulin dependent diabetics suffering from different types of diabetic retinopathy to evaluate the effect of growth hormone suppression on glycemic control and other hormonal changes in diabetic retinopathy. Blood levels of HGH, prolactin, C-peptide, glucagon and A.C.T.H. were determined by RIA. Tests of glycemic control including glycosylated hemoglobin [HbA[1c]], fasting and postprandial blood sugar and total blood lipids were also estimated. Retinal changes were studied by fluorescein angiography. Bromocriptine was given to all cases for 12 weeks, in addition to standard therapy [insulin+ diet]. Pretreatment investigations were repeated at the end of the study. Pretreatment investigations showed significant elevation of glycosylated hemoglobin, fasting and postprandial blood sugar. Serum growth hormone, plasma glucagon and A.C.T.H. were significantly high. C-peptide was measurable in 30% of patients. After three months treatment, tests of glycemic control were significantly decreased. Serum GH and prolactin decreased significantly, while C-peptide was increased. Glucagon and A.C.T.H. showed no change. After treatment, retinal changes deteriorated in 60% of patients and this was attributed to a hypoglycemic effect