Summary
The experiments were performed in 4-day, 4-week, and 4-month olds rats. The total
binding capacity of high affinity receptors for 3H-naloxone and 3H-corticosterone 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 3H-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. In contrast, the maximal binding capacity of lymphocytes for 3H-naloxone showed a significant decline with age. Changes in the binding capacity
for the two ligands refer to changes in composition of cells within the thymus and
to alterations in cell system in sensitivity to either corticosteroids or opioids.
Key words
Thymus-derived lymphocytes - Naloxone binding - Corticosterone binding - Thymocytes
and age
