Characterization of three corticotropin-releasing factor receptors in catfish: a novel third receptor is predominantly expressed in pituitary and urophysis

Endocrinology. 2001 Jan;142(1):446-54. doi: 10.1210/endo.142.1.7879.


The present study reports the isolation of three complementary DNA (cDNA) clones encoding distinct subtypes of CRF receptors from the diploid catfish (cf) species, Ameiurus nebulosus. The first clone encodes a 446-amino acid protein (cfCRF-R1) that is highly homologous to mouse (m) CRF-R1 (93% identical). The cfCRF-R1 messenger RNA is highly expressed in the brain, and its distribution pattern correlates well with that of mammalian CRF-R1, except for weak expression in the pituitary. When transiently expressed in COS-7 cells, cfCRF-R1 bound CRF, urotensin I, and sauvagine with similar affinities. The second full-length cDNA, which was cloned from catfish heart, encodes a 406-amino acid protein that showed homology to murine CRF-R2 (88%) and when expressed in COS-7 cells preferentially bound sauvagine. The highest level of cfCRF-R2 expression was observed in the heart. The third full-length cDNA clone, which encodes a 428-amino acid protein, is structurally closer to cfCRF-R1 (85%) than to cfCRF-R2 (80%). This novel CRF receptor (cfCRF-R3) bound CRF with a 5-fold higher affinity than urotensin I and sauvagine and was expressed in the pituitary gland, urophysis, and brain. The presence of three different CRF receptors, each with distinct tissue distribution and ligand binding properties, suggests a complex CRF/urotensin I system.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Brain / physiology*
  • COS Cells
  • Catfishes
  • Chlorocebus aethiops
  • Cloning, Molecular
  • Conserved Sequence
  • Glycosylation
  • Humans
  • Mice
  • Molecular Sequence Data
  • Neurosecretory Systems / physiology*
  • Organ Specificity
  • Phylogeny*
  • Pituitary Gland / physiology*
  • Receptors, Corticotropin-Releasing Hormone / chemistry
  • Receptors, Corticotropin-Releasing Hormone / genetics*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Transfection
  • Xenopus


  • CRF receptor type 2
  • CRF receptor type 3
  • Receptors, Corticotropin-Releasing Hormone
  • CRF receptor type 1

Associated data

  • GENBANK/AF229359
  • GENBANK/AF229360
  • GENBANK/AF229361