Plasma corticosterone in stressed magnesium-deficient weanling rats.
A study was undertaken to learn whether the young Mg-deficient mammal can respond to major stress with increased levels of plasma corticosterone. Plasma corticosterone was determined in 48 weanling rats with dietary Mg deficiency and in 48 Mg-sufficient controls fed a Mg-supplemented diet, studying 12 animals at a time on experimental day 14. Each animal was studied once, either in an unstressed state or after the stress of audiogenic or strychnine seizures. Plasma corticosterone was determined using a radioimmunoassay; Mg was analyzed by atomic absorption spectrophotometry. On experimental day 14, unstressed Mg-deficient rats were tremulous, hyperirritable and showed slightly increased plasma corticosterone levels that exceeded controls levels. After strychnine shock, the mean plasma corticosterone levels of Mg-sufficient and Mg-deficient rats were both significantly increased over resting levels, and were not statistically different. Moreover, the spontaneous mortality rate that occurred during the experimental period in all Mg-sufficient rats was 0 compared to 27% among all Mg-deficient animals (p less than 0.0001). It was concluded that young rats deficient in Mg for 2 weeks could respond to major stress with levels of plasma corticosterone that were not significantly different from values of equally stressed Mg-sufficient controls. The deficient animals suffered a higher mortality, providing support for the concept that Mg deficiency increases stress-induced mortality in animals.
Caddell
J L
JL
Division of Disorders of Carbohydrate Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Md.
Dunn
J D
JD
D000818:Animals; D001842:Bone and Bones / Q000737:chemistry; D003345:Corticosterone / Q000097:blood*; D008274:Magnesium / Q000097:blood; D008275:Magnesium Deficiency / Q000097:blood*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013312:Stress, Physiological / Q000097:blood*
D008274:Magnesium; D003345:Corticosterone