Corticotropin-releasing factor (CRF) receptors in intermediate lobe of the pituitary: Biochemical characterization and autoradiographic localization

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Peptides (Fayetteville, N.Y.); (United States)

DOI:https://doi.org/10.1016/0196-9781(89)90095-8· OSTI ID:5822240

Grigoriadis, D E; De Souza, E B

CRF receptors were characterized using radioligand binding and chemical affinity cross-linking techniques and localized using autoradiographic techniques in porcine, bovine and rat pituitaries. The binding of 125I-(Tyr0)-ovine CRF (125I-oCRF) to porcine anterior and neurointermediate lobe membranes was saturable and of high affinity with comparable KD values (200-600 pM) and receptor densities (100-200 fmoles/mg protein). The pharmacological rank order of potencies for various analogs and fragments of CRF in inhibiting 125I-oCRF binding in neurointermediate lobe was characteristic of the well-established CRF receptor in anterior pituitary. Furthermore, the binding of 125I-oCRF to both anterior and neurointermediate lobes of the pituitary was guanine nucleotide-sensitive. Affinity cross-linking studies revealed that the molecular weight of the CRF binding protein in rat intermediate lobe was identical to that in rat anterior lobe (Mr = 75,000). While the CRF binding protein in the anterior lobes of porcine and bovine pituitaries had identical molecular weights to CRF receptors in rat pituitary (Mr = 75,000), the molecular weight of the CRF binding protein in porcine and bovine intermediate lobe was slightly higher (Mr = 78,000). Pituitary autoradiograms from the three species showed specific binding sites for 125I-oCRF in anterior and intermediate lobes, with none being apparent in the posterior pituitary. The identification of CRF receptors in the intermediate lobe with comparable characteristics to those previously identified in the anterior pituitary substantiate further the physiological role of CRF in regulating intermediate lobe hormone secretion.

• Research Organization: NIDA Addiction Research Center, Baltimore, MD (USA)
• OSTI ID: 5822240
• Journal Information: Peptides (Fayetteville, N.Y.); (United States), Journal Name: Peptides (Fayetteville, N.Y.); (United States) Vol. 10:1; ISSN PPTDD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACTH
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
CATTLE
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL COMPOSITION
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MOLECULAR WEIGHT
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
RUMINANTS
SWINE
VERTEBRATES