Receptors for corticotropin-releasing hormone in human pituitary: Binding characteristics and autoradiographic localization to immunocytochemically defined proopiomelanocortin cells

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Journal of Clinical Endocrinology and Metabolism; (United States)

DOI:https://doi.org/10.1210/jcem-73-2-268· OSTI ID:5323346

Smets, G; Vauquelin, G; Moons, L; Smitz, J; Kloeppel, G ^[1]

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1. Department of Experimental Pathology, Vrije Universiteit Brussel (Belgium)

Using autoradiography combined with immunocytochemistry, the authors demonstrated that the target cells of CRH in the human pituitary were proopiomelanocortin cells. Scatchard analysis of (125I)Tyr0-oCRH saturation binding revealed the presence of one class of saturable, high affinity sites on pituitary tissue homogenate. The equilibrium dissociation constant (Kd) for (125I)Tyr0-oCRH ranged from 1.1-1.6 nM, and the receptor density was between 200-350 fmol/mg protein. Fixation of cryostat sections with 4% paraformaldehyde before tracer incubation improved both tissue preservation and localization of the CRH receptor at the cellular level. Additional postfixation with 1% glutaraldehyde inhibited tracer diffusion during subsequent immunocytochemistry and autoradiography. (125I)Tyr0-oCRH was found in cytoplasmic inclusions or at the cell periphery of ACTH/beta-endorphin cells in the anterior pituitary. Single cells of the posterior pituitary were also CRH receptor positive. Cells staining for PRL or GH were CRH receptor negative. They conclude that CRH binds only to high affinity receptors on ACTH/{beta}-endorphin cells in the human pituitary.

• OSTI ID: 5323346
• Journal Information: Journal of Clinical Endocrinology and Metabolism; (United States), Journal Name: Journal of Clinical Endocrinology and Metabolism; (United States) Vol. 73:2; ISSN JCEMA; ISSN 0021-972X
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BODY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
GLANDS
HORMONES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MAN
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY GLAND
PITUITARY HORMONES
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
VERTEBRATES