Evidence for glucocorticoid receptor in human leukocytes

Area of Science:

• Biochemistry
• Cell Biology
• Immunology

Background:

• Glucocorticoids are crucial hormones with diverse physiological effects.
• Understanding glucocorticoid uptake mechanisms is vital for pharmacology and disease research.
• Leukocytes play a key role in immune responses and are targets for glucocorticoid therapy.

Purpose of the Study:

• To investigate the in vitro uptake of glucocorticoids by human peripheral leukocytes.
• To characterize the components of glucocorticoid uptake in these cells.
• To determine if human leukocyte glucocorticoid uptake involves specific receptors, similar to those in other species.

Main Methods:

• In vitro incubation of human peripheral leukocytes with glucocorticoids.
• Analysis of uptake kinetics, including saturable and non-saturable components.
• Comparison of human leukocyte uptake with known glucocorticoid receptor characteristics in rabbit granulocytes.
• Study of glucocorticoid uptake in cells from patients with chronic lymphatic leukemia and chronic myeloid leukemia.

Main Results:

• Human peripheral leukocyte glucocorticoid uptake comprises both saturable and non-saturable components.
• The saturable component exhibits characteristics (structural specificity, time course, metabolic sensitivity, half-saturation concentration) consistent with a specific glucocorticoid receptor.
• Cells from chronic lymphatic leukemia demonstrated saturable glucocorticoid uptake, while chronic myeloid leukemia cells did not.

Conclusions:

• Human peripheral leukocytes possess a specific glucocorticoid receptor mediating saturable uptake.
• This receptor shares similarities with the known glucocorticoid receptor in rabbit granulocytes.
• Saturable glucocorticoid uptake is present in chronic lymphatic leukemia cells but not in chronic myeloid leukemia cells, suggesting differential receptor expression or function in these leukemias.