Serum Growth Hormone Levels and the Response of Diabetic Retinopathy to Pituitary Ablation

Abstract

Summary: Serum growth hormone levels were measured during insulin tolerance tests in 36 patients after yttrium-90 pituitary implantation for diabetic retinopathy.

Physical Growth and Retinopathy in Preterm Infants: Involvement of IGF-I and GH

“…Several clinical studies showed that the pathogenesis of proliferative diabetic retinopathy was mediated by GH through its positive effect on the proliferation of endothelial cells (13)(14)(15)(16). A previous case report demonstrated that patients with GH deficiency showed a reduced retinal vascularization during childhood (25), and GH replacement therapy for patients with GH deficiency induced diabeticlike retinopathy (26), which was remitted after discontinuation of GH treatment (27).…”

“…It has been postulated that GH plays a role in initiating and sustaining angiopathic processes. In previous reports, the association between GH exposure and ischemia-induced retinal neovascularization was determined in diabetic patients (13)(14)(15)(16). Accordingly, it is likely that continuous exposure to high GH causes progression of ROP in preterm infants.…”

Medical treatment of diabetic retinopathy

“…Improvement in the degree of proliferative retinopathy was found to correlate with the postablation level of growth hormone, determined on an insulin stress test, and correlated with decreasing levels of peak serum growth hormone production. 41 However, half of the patients who achieved maximum postablation reductions of growth hormone production demonstrated no change or even worsening of diabetic proliferative retinopathy. 41 Subsequently, research into the role of growth factors in angiogenesis has focused on the release of the major angiogenic growth factors produced from retinal tissue in response to retinal ischaemia.…”

“…41 However, half of the patients who achieved maximum postablation reductions of growth hormone production demonstrated no change or even worsening of diabetic proliferative retinopathy. 41 Subsequently, research into the role of growth factors in angiogenesis has focused on the release of the major angiogenic growth factors produced from retinal tissue in response to retinal ischaemia. Identified local retinal angiogenic growth factors are vascular endothelial growth factor (VEGF), insulin-like growth factor 1 (IGF1), and PDGF, with growth factors derived from ischaemic retinal tissue being more important in the causation of proliferative diabetic retinopathy than pituitary-derived growth factors.…”

Ocular neovascularization: a valuable model system

“…Ever since the demonstration that hypophosectomy has an ameliorative effect on proliferative diabetic retinopathy, it has been suspected that growth hormone (GH) and/or insulin-like growth factor-1 (IGF1) contribute to retinal neovascularization (Wright et al, 1969). In support of this hypothesis, antagonists of GH or IGF-1 decrease retinal neovascularization by 30-50% (Smith et al, 1997).…”