TY - JOUR
T1 - Retinal microvessels express less gamma-glutamyl transpeptidase than brain microvessels
AU - Belloni-Olivi, Luisa
AU - Brassier, Joseph P.
AU - Goldstein, Gary W.
PY - 1992/1/1
Y1 - 1992/1/1
N2 - In this investigation we localized and compared the level of gamma-glutamyl transpeptidase (GGTP) activity in retinal and brain preparations using histochemical, enzymatic and in situ hybridization assays. We compared GGTP distribution to another microvessel specific enzyme, alkaline phosphatase (AP). In the rat brain, GGTP activity was observed in microvessels and choroid plexus by a histochemical method. Similar studies in the rat retina revealed activity in the pigment epithelium but only a very weak reaction in microvessels. Histochemical staining for alkaline phosphatase was observed in both retinal and brain microvessels choroid plexus and pigment epithelium. Biochemical analysis verified that GGTP activity was significantly lower in retinal than brain microvessels, while alkaline phosphatase activity was similar in both types of microvessels. GGTP specific activity of bovine brain and retinal microvessels was 185+39 mUnits and 8.5+1.5 mUnits (p<0.001), respectively. By contrast, alkaline phosphatase specific activity in brain and retinal microvessels was 732+139 and 471+114 (p<0.1), respectively. Choroid plexus and retinal pigment epithelium exhibited similar levels of GGTP and alkaline phosphatase. Differences in GGTP expression between retinal and brain microvessels were also observed on the mRNA level. In situ hybridization studies revealed that brain microvessels expressed four times more GGTP specific mRNA than retinal microvessels. We conclude that retinal microvessels do not express high levels of GGTP which may make them more vulnerable than brain microvessels to injuries mediated by leukotrienes and oxidative stress.
AB - In this investigation we localized and compared the level of gamma-glutamyl transpeptidase (GGTP) activity in retinal and brain preparations using histochemical, enzymatic and in situ hybridization assays. We compared GGTP distribution to another microvessel specific enzyme, alkaline phosphatase (AP). In the rat brain, GGTP activity was observed in microvessels and choroid plexus by a histochemical method. Similar studies in the rat retina revealed activity in the pigment epithelium but only a very weak reaction in microvessels. Histochemical staining for alkaline phosphatase was observed in both retinal and brain microvessels choroid plexus and pigment epithelium. Biochemical analysis verified that GGTP activity was significantly lower in retinal than brain microvessels, while alkaline phosphatase activity was similar in both types of microvessels. GGTP specific activity of bovine brain and retinal microvessels was 185+39 mUnits and 8.5+1.5 mUnits (p<0.001), respectively. By contrast, alkaline phosphatase specific activity in brain and retinal microvessels was 732+139 and 471+114 (p<0.1), respectively. Choroid plexus and retinal pigment epithelium exhibited similar levels of GGTP and alkaline phosphatase. Differences in GGTP expression between retinal and brain microvessels were also observed on the mRNA level. In situ hybridization studies revealed that brain microvessels expressed four times more GGTP specific mRNA than retinal microvessels. We conclude that retinal microvessels do not express high levels of GGTP which may make them more vulnerable than brain microvessels to injuries mediated by leukotrienes and oxidative stress.
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U2 - 10.3109/02713689209001771
DO - 10.3109/02713689209001771
M3 - Article
C2 - 1350241
AN - SCOPUS:0026585125
VL - 11
SP - 203
EP - 211
JO - Current Eye Research
JF - Current Eye Research
SN - 0271-3683
IS - 3
ER -