Patterns of Radioactivity in the Eyes of Rats after Injection of Iodinated Prolactin

Wk, O'Steen; Dk, Sundberg

doi:10.1159/000265174

Cited by 20 publications

(11 citation statements)

References 13 publications

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“…PRL is found in the aqueous humor of the human eye (29,68), and both PRL and vasoinhibins are present in rat retina (3,71). Some ocular PRL may originate from systemic PRL entering the eye because iodinated PRL injected intracardially can be incorporated into the retina, choroids, and ciliary body (62). However, PRL and vasoinhibins can also be synthesized intraocularly.…”

Section: Vasoinhibins Are Natural Inhibitors Of Ocular Angiogenesismentioning

confidence: 99%

Vasoinhibins: novel inhibitors of ocular angiogenesis

Clapp¹,

Thebault²,

Arnold³

et al. 2008

American Journal of Physiology-Endocrinology and Metabolism

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Disruption of the quiescent state of blood vessels in the retina leads to aberrant vasopermeability and angiogenesis, the major causes of vision loss in diabetic retinopathy. Prolactin is expressed throughout the retina, where it is proteolytically cleaved to vasoinhibins, a family of peptides (including the 16-kDa fragment of prolactin) with potent antiangiogenic, vasoconstrictive, and antivasopermeability actions. Ocular vasoinhibins act directly on endothelial cells to block blood vessel growth and dilation and to promote apoptosis-mediated vascular regression. Also, vasoinhibins prevent retinal angiogenesis and vasopermeability associated with diabetic retinopathy, and inactivation of endothelial nitric oxide synthase via protein phosphatase 2A is among the various mechanisms mediating their actions. Here, we discuss the potential role of vasoinhibins both in the maintenance of normal retinal vasculature and in the cause and prevention of diabetic retinopathy and other vasoproliferative retinopathies.

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Section: Vasoinhibins Are Natural Inhibitors Of Ocular Angiogenesismentioning

confidence: 99%

Vasoinhibins: novel inhibitors of ocular angiogenesis

Clapp¹,

Thebault²,

Arnold³

et al. 2008

American Journal of Physiology-Endocrinology and Metabolism

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“…PRL is expressed throughout retina [4]. One animal study proved that intracardiac radioactive PRL injection will incorporate into ocular tissue [8]. A study reported that PRL level is increased in diabetics and it is lower in patients with retinopathy than in diabetics without retinopathy [9].…”

Section: Introductionmentioning

confidence: 99%

Serum Prolactin Level and Diabetic Retinopathy in Type 2 Diabetes Prolactin and Diabetic Retinopathy

Bonakdaran¹,

Shoeibi²,

Abrishami³

et al. 2012

J Diabetes Metab

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Retinopathy is a common complication of type 2 diabetes. Several factors including hyperglycemia and hypertension play important roles in retinopathy progression. However, the actual mechanistic pathways are not yet discovered. Prolactin via its antiangiogenic characteristics may exert protective effects on retina. We performed a case-control study in order to investigate the potential role of 23KD prolactin in retinopathy.A total of 212 type 2 diabetics were recruited in this study. According to retinopathy they were divided into two groups. Group one (70 patients) suffered diabetic retinopathy and group two (142 patients) did not have retinopathy. There were significant differences in diabetes duration and hyperglycemia and systolic hypertension between two groups (p<0.05). However we did not find any significant difference in prolactin level between two groups (p>0.05). Serum 23 KD prolactin does not seem to have protective role in diabetes retinopathy.

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“…Vasoinhibins are present in the retina (6), and because radioactive PRL injected intracardially is incorporated into ocular tissues (ciliary body, choroid, and retina) (7), we reasoned that a portion of ocular vasoinhibins could originate from the intraocular cleavage of PRL coming from the circulation; therefore, high levels of serum PRL in diabetic patients may restrain DR progression.…”

mentioning

confidence: 99%

High Levels of Serum Prolactin Protect Against Diabetic Retinopathy by Increasing Ocular Vasoinhibins

et al. 2010

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OBJECTIVEIncreased retinal vasopermeability (RVP) occurs early in diabetes and is crucial for the development of sight-threatening proliferative diabetic retinopathy (DR). The hormone prolactin (PRL) is proteolytically processed to vasoinhibins, a family of peptides that inhibit the excessive RVP related to DR. Here, we investigate the circulating levels of PRL in association with DR in men and test whether increased circulating PRL, by serving as a source of ocular vasoinhibins, can reduce the pathological RVP in diabetes.RESEARCH DESIGN AND METHODSSerum PRL was evaluated in 40 nondiabetic and 181 diabetic men at various stages of DR. Retinal vasoinhibins were measured in rats rendered hyperprolactinemic by placing two anterior pituitary grafts under the kidney capsule and in PRL receptor–null mice. RVP was determined in hyperprolactinemic rats subjected to the intraocular injection of vascular endothelial growth factor (VEGF) or made diabetic with streptozotocin.RESULTSThe circulating levels of PRL increased in diabetes and were higher in diabetic patients without retinopathy than in those with proliferative DR. In rodents, hyperprolactinemia led to vasoinhibin accumulation within the retina; genetic deletion of the PRL receptor prevented this effect, indicating receptor-mediated incorporation of systemic PRL into the eye. Hyperprolactinemia reduced both VEGF-induced and diabetes-induced increase of RVP. This reduction was blocked by bromocriptine, an inhibitor of pituitary PRL secretion, which lowers the levels of circulating PRL and retinal vasoinhibins.CONCLUSIONSCirculating PRL influences the progression of DR after its intraocular conversion to vasoinhibins. Inducing hyperprolactinemia may represent a novel therapy against DR.

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Patterns of Radioactivity in the Eyes of Rats after Injection of Iodinated Prolactin

Cited by 20 publications

References 13 publications

Vasoinhibins: novel inhibitors of ocular angiogenesis

Vasoinhibins: novel inhibitors of ocular angiogenesis

Serum Prolactin Level and Diabetic Retinopathy in Type 2 Diabetes Prolactin and Diabetic Retinopathy

High Levels of Serum Prolactin Protect Against Diabetic Retinopathy by Increasing Ocular Vasoinhibins

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