Adrenocorticotropic hormone stimulates a transient calcium uptake in rat lymphocytes.

Academic Article

Abstract

  • Freshly isolated rat lymphocytes were tested for corticotropin (ACTH)-dependent calcium uptake. Physiological levels of corticotropin (0.01-1 nM) were found to stimulate both an uptake of 45Ca2+ and a rise in cAMP. The calcium uptake was delayed by 2 min after ACTH addition, but was rapid and transient after the onset of uptake. The extent of calcium uptake was dose dependent on the corticotropin concentration and reached a maximum by 1 nM. Several fragments of corticotropin were tested for activity; both full-length 1-39 and a functional truncated form, 1-25, had equivalent effects on 45Ca influx at 1 nM; however, alpha MSH-(1-13), ACTH-(11-24), or a mixture of alpha MSH and ACTH-(11-24) had no effect on 45Ca influx. Extracellular calcium uptake was blocked by the calcium channel blockers lanthanum, diltiazem, nifedipine, and omega-conotoxin. Splenic lymphocytes that express ACTH receptors had ligand-dependent calcium uptake, but thymocytes that lack ACTH receptors had no ligand-dependent calcium uptake. A mouse adrenal cell line, Y-1, showed the same 45Ca uptake kinetics. These findings demonstrate that both lymphocytes and adrenal cells have a functional ACTH-dependent calcium uptake mechanism.

    • Authors

    Keywords

  • Adrenal Glands, Adrenocorticotropic Hormone, Animals, Base Sequence, Calcium, Cells, Cultured, Cyclic AMP, Dose-Response Relationship, Drug, Lanthanum, Lymphocytes, Male, Molecular Sequence Data, Nifedipine, Peptides, Rats, Rats, Sprague-Dawley, Thymus Gland, Time Factors, omega-Conotoxins

    • Digital Object Identifier (doi)

    Pubmed Id

  • 16607017

    • Author List

  • Clarke BL; Moore DR; Blalock JE

    • Start Page

  • 1780

    • End Page

  • 1786

    • Volume

  • 135

    • Issue

  • 5