TY - JOUR
T1 - Differential expression of functional adrenocorticotropic hormone receptors by subpopulations of lymphocytes
AU - Clarke, B. L.
AU - Bost, K. L.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1989
Y1 - 1989
N2 - In an effort to investigate the presence of adrenocorticotropic hormone (ACTH) receptors on rat lymphocytes, cells were separated by a panning procedure into T and B cell populations. By using the radiolabeled ACTH agonist, (125I-Tyr23) phenylalanine2-norleucine4-ACTH1-24, substantial numbers of ACTH binding sites were detected on T and B lymphocytes, but not on thymocytes. Scatchard analysis revealed two types of binding sites on each cell population, one with K(d1) = 0.088 ± 0.025 nM and one with K(d2) = 4.2 ± 0.6 nM; however, the absolute number of binding sites per cell was different. B lymphocytes expressed approximately three times the number of K(d1) binding sites per cell when compared with T lymphocytes. However, ACTH receptor expression by these cell populations was not static as suggested by the ability to induce receptor expression via mitogens. B or T cells and thymocytes stimulated with the mitogens LPS or Con A, respectively, substantially increased their number of K(d1) binding sites per cell (approximately three-fold). Even more dramatic increases in K(d1) receptor expression (approximately 100-fold) were observed when comparing 'normal' and stimulated thymocytes. To demonstrate that these ACTH binding sites were in fact functional, cAMP levels were measured in lymphocytes 10 min after exposure to varying concentrations of ACTH. Dose-dependent increases in cAMP levels were observed, with significant stimulation occurring with as little as 0.1 nM ACTH added. Taken together, these studies demonstrate the presence of functional ACTH receptors on normal, rat T and B lymphocytes.
AB - In an effort to investigate the presence of adrenocorticotropic hormone (ACTH) receptors on rat lymphocytes, cells were separated by a panning procedure into T and B cell populations. By using the radiolabeled ACTH agonist, (125I-Tyr23) phenylalanine2-norleucine4-ACTH1-24, substantial numbers of ACTH binding sites were detected on T and B lymphocytes, but not on thymocytes. Scatchard analysis revealed two types of binding sites on each cell population, one with K(d1) = 0.088 ± 0.025 nM and one with K(d2) = 4.2 ± 0.6 nM; however, the absolute number of binding sites per cell was different. B lymphocytes expressed approximately three times the number of K(d1) binding sites per cell when compared with T lymphocytes. However, ACTH receptor expression by these cell populations was not static as suggested by the ability to induce receptor expression via mitogens. B or T cells and thymocytes stimulated with the mitogens LPS or Con A, respectively, substantially increased their number of K(d1) binding sites per cell (approximately three-fold). Even more dramatic increases in K(d1) receptor expression (approximately 100-fold) were observed when comparing 'normal' and stimulated thymocytes. To demonstrate that these ACTH binding sites were in fact functional, cAMP levels were measured in lymphocytes 10 min after exposure to varying concentrations of ACTH. Dose-dependent increases in cAMP levels were observed, with significant stimulation occurring with as little as 0.1 nM ACTH added. Taken together, these studies demonstrate the presence of functional ACTH receptors on normal, rat T and B lymphocytes.
UR - http://www.scopus.com/inward/record.url?scp=0024365082&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024365082&partnerID=8YFLogxK
M3 - Article
C2 - 2544644
AN - SCOPUS:0024365082
SN - 0022-1767
VL - 143
SP - 464
EP - 469
JO - Journal of Immunology
JF - Journal of Immunology
IS - 2
ER -