Abstract
Concurrent with 8- to 10-fold increases in levels of serum corticosterone, protein deficient (PD) weanling mice experienced 10-fold decreases in cell yields compared to protein sufficient (PS) weanling mice. Flow cytometric analysis of PD thymocyte subpopulations indicated that the number of cells in all PD thymocyte subpopulations were reduced. When PD mice were refed after 21 days by being placed on PS diets, their serum corticosterone rapidly decreased to normal levels concurrent with the onset of thymic regeneration, thus substantiating the direct correlation between elevated serum corticosterone and thymic atrophy noted above. Flow cytometric analysis of thymocyte subpopulations in these former PD mice indicated rapid expansion of immature CD4+/CD8+ and CD4-/CD8- cell subpopulations prior to expansion of mature CD4+ and CD8+ cell subpopulations. In addition, CD3 expression of thymocytes in former PD mice decreased to normal levels during the refeeding period.