Effects of lead on glucose metabolism, ion flux, and collagen synthesis in cerebral capillaries of calves.
Brain capillary function was assessed in 4- to 6-week-old calves given lead acetate (15 mg/kg of body weight) orally for 7 to 8 days. Neurologic signs of lead poisoning included CNS depression, blindness, and hyperesthesia. Brain capillaries were isolated from cerebral cortex of control and lead-treated calves and evaluated for metabolic indicators, ion transport, and prolyl hydroxylase activity. In lead-treated calves, the rate of glucose metabolism was less than half that in controls. Ion efflux of 45Ca or 36Cl from endothelial cell suspensions was not affected by lead treatment. Prolyl hydroxylase activity in endothelium and proline-to-hydroxyproline ratio in endothelial basement membranes were similar in control and lead-poisoned calves. Results indicate that lead may inhibit energy metabolism, but not ion transport or collagen biosynthesis in brain capillaries of calves and, compared with suckling rats, damage to the blood-brain barrier is less important. In calves, neuronal tissue may be the primary target for the CNS effects of lead.
Department of Veterinary Physiology and Pharmacology, Iowa State University, Ames 50011.
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Ahrens
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002196:Capillaries / Q000187:drug effects / Q000378:metabolism*; D002417:Cattle; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D002712:Chlorides / Q000378:metabolism*; D003094:Collagen / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis / Q000187:drug effects*; D007854:Lead / Q000097:blood; D007855:Lead Poisoning / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009942:Organometallic Compounds / Q000633:toxicity*; D011393:Procollagen-Proline Dioxygenase / Q000378:metabolism
D000596:Amino Acids; D002712:Chlorides; D009942:Organometallic Compounds; D007854:Lead; D003094:Collagen; D011393:Procollagen-Proline Dioxygenase; D005947:Glucose; C008261:lead acetate; D002118:Calcium