Cyclic AMP and GMP levels in thymocytes and splenic T and B lymphocytes in protein deprived rats.

Cyclic nucleotide levels were determined in thymocytes and in splenic T and B lymphocytes separated by nylon wool filtration. In control rats, thymocytes contained less cAMP and cGMP than splenic T cells. The level of cGMP was lower, and consequently cAMP:cGMP ratio was higher in splenic B than in T cells. Protein deprivation increased the nucleotide ratios in both T and B splenic lymphocytes; this effects was due to a decrease in the cGMP levels in the case of the T cells and to an increase in the cAMP levels in the B cells. These data could be related to the reduced mitotic activity of the splenic lymphocytes. However, the nylon-nonadherent thmyocytes of protein deprived rats paradoxically displayed increased cGMP contents without changes in the cAMP levels, despite the drop in their proliferative potential. The impairment of cyclic nucleotide metabolism may intervene in the immunological disturbances due to protein malnutrition.