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-brain barrier (BBB) is unknown. This investigation was undertaken to examine vascular permeability to I-125-labelled rat growth hormone (rGH) in the central nervous system (CNS) of normal animals. Since age and spinal cord injury influences the metabolism of GH, these factors were also included. No statistically significant difference was seen regarding 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 into the right dorsal horn of the T10-11 segments in young animals, increased rGH permeability in several spinal cord segments at 0.5-5.0 h after injury. This permeability increase progressed over time. Similar trauma to old rats resulted in a significantly less increase in rGH permeability in the spinal cord 5 h after the trauma. This indicates that trauma-induced increased permeability of rGH is age-dependent, Pretreatment of normal young animals with a new antioxidant (H 290/51) did not influence the rGH permeability. However, the drug prevented the trauma-induced increase of rGH permeability at 5 h after injury. This indicates that inhibition of lipid peroxidation has some protective effect on trauma-induced increase in rGH permeability.