Changes of hypothalamic-pituitary-adrenal-thymus (HPAT) functional axis in rats after neonatal trea

AIM:To observe the changes of HPAT axis with lesion of arcuate nucleusMETHODS:Newborn Sprahue-Dawley rats were given subcutaneous injection of 4mg/g of monosodium glutamate (MSG) on days 2,4,6,8,10 of postnatal life, after they were adult, the morphological and functional changes of HPAT axis were examined. RESULTS:MSG-rats showed an increase of the weight of pituitary per 100gram body weight, while there were no difference in the weights of adrenal and thymus; the number of corticotropin releasing hormone (CRH) immunoreactive (IR) positive cells in paraventricular nucleus , CRH IR positive nerve teminals in ME and ACTH IR positive cells in pituitary increased significantly; baseline of plasma ACTH and corticosterone rose. Thymus atrophied with lymphocytes showing proliferative reactivity with natural killer cell cytotoxicity activity, productivity of IL-2 and interferon-γ declines significantly.CONCLUSION: MSG-rats showed hypofunction of HPA axis and the cellular immunofunction was inhibited.