VASCULAR-PERMEABILITY TO GROWTH-HORMONE IN THE RAT CENTRAL-NERVOUS-SYSTEM AFTER FOCAL SPINAL-CORD INJURY - INFLUENCE OF A NEW ANTIOXIDANT H-290 51 AND AGE/

Vascular permeability to the growth hormone (GH) across the blood-brai n barrier (BBB) is unknown. This investigation was undertaken to exami ne vascular permeability to I-125-labelled rat growth hormone (rGH) in the central nervous system (CNS) of normal animals. Since age and spi nal cord injury influences the metabolism of GH, these factors were al so included. No statistically significant difference was seen regardin g rGH permeability between young (aged 19-21 weeks) and old (age 38-42 weeks) animals. A focal trauma to the cord, produced by an incision i nto the right dorsal horn of the T10-11 segments in young animals, inc reased rGH permeability in several spinal cord segments at 0.5-5.0 h a fter injury. This permeability increase progressed over time. Similar trauma to old rats resulted in a significantly less increase in rGH pe rmeability in the spinal cord 5 h after the trauma. This indicates tha t trauma-induced increased permeability of rGH is age-dependent, Pretr eatment of normal young animals with a new antioxidant (H 290/51) did not influence the rGH permeability. However, the drug prevented the tr auma-induced increase of rGH permeability at 5 h after injury. This in dicates that inhibition of lipid peroxidation has some protective effe ct on trauma-induced increase in rGH permeability.