Age-related changes in adrenocorticoid and opioid receptor capacity of Thymus-derived lymphocytes in rats

The experiments were performed in 4-day, 4-week, and 4-month olds rats. The total binding capacity of high affinity receptors for 3 H-naloxone and 3 H-costicosterone in thymus-derived lymphocytes was measured in vitro. There was no change in the affinity constant of the receptors for the ligands during the life-time mentioned before. The maximal binding capacity for 3 H-corticosterone in thymus-derived lymphocytes showed a marked increase in 1-month and 4-month old ages as compared to the values obtained by the end of the first postnatal week