Alteration of opioid peptide concentrations in the rat pituitary following survivable closed head injury.
Concentration changes of methionine enkephalin-like immunoreactivity (ME-li) and beta-endorphin-like immunoreactivity (BE-li) in the rat pituitary following diffuse brain injury were studied. Closed head injury was induced by a weight-drop trauma device (450 g x 2 m). The level of closed head injury used in this study altered the pituitary opioid peptide concentrations. The level of ME-li did not change in the experimental groups 3 hours, 10 hours, 24 hours, and 3 days after the trauma, but significantly increased by 34% 10 days after the trauma. BE-li remained constant 3 hours and 10 hours following the injury, increased by 48% at 24 hours, and remained at this level for 10 days after the trauma (44% at 3 days, and 40% at 10 days). The levels of ME-li and BE-li in the control sham-operated rats did not change during these times. The present measurements of BE-li and ME-li in the pituitary indicate that the opioid peptides that derive from two different neuropeptidergic systems, proopiomelanocortin (POMC) and preproenkephalin A, respectively, may participate in the pathophysiology of a closed head injury.
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004744:Enkephalin, Methionine / Q000032:analysis / Q000378:metabolism*; D016489:Head Injuries, Closed / Q000378:metabolism*; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D013997:Time Factors; D001615:beta-Endorphin / Q000032:analysis / Q000378:metabolism*
D004744:Enkephalin, Methionine; D001615:beta-Endorphin