Structural determination and histochemical localization of ghrelin in the red-eared slider turtle, Trachemys scripta elegans

Gen Comp Endocrinol. 2004 Aug;138(1):50-7. doi: 10.1016/j.ygcen.2004.05.005.

Abstract

We purified ghrelin peptide and determined the cDNA sequence encoding the precursor protein from the stomach of the red-eared slider turtle, Trachemys scripta elegans. The Trachemys ghrelin is comprised of 25-amino acids and has the sequence GSSFLSPEYQNTQQRKDPKKHTKLN. The third serine residue was modified by n-octanoic (C8:0), decanoic (C10:0) or unsaturated decanoic acid (C10:1). The carboxyl-terminal end of the peptide was not amidated, as seen in the ghrelins of other land vertebrates. Quantitative real-time PCR analysis revealed high levels of gene expression in the stomach and moderate levels in the large intestine and pancreas. Histochemical studies of turtle stomach revealed that ghrelin-immunopositive (ghrelin-ip) cells, which were small and round, were observed in the mucosal layer of the stomach but not in the myenteric plexus, and ghrelin-mRNA-expressing (ghrelin-ex) cells detected by in situ hybridization were scattered in a similar distribution as ghrelin-ip cells. These results indicate that ghrelin is present in reptiles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • CHO Cells
  • Cricetinae
  • DNA, Complementary / biosynthesis
  • DNA, Complementary / genetics
  • Gastric Mucosa / metabolism*
  • Gene Expression Regulation / physiology
  • Ghrelin
  • Immunohistochemistry
  • Mass Spectrometry
  • Molecular Sequence Data
  • Oligonucleotide Probes
  • Peptide Hormones / biosynthesis
  • Peptide Hormones / genetics
  • Peptide Hormones / physiology*
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Stomach / anatomy & histology
  • Stomach / cytology
  • Turtles / physiology*

Substances

  • DNA, Complementary
  • Ghrelin
  • Oligonucleotide Probes
  • Peptide Hormones
  • RNA, Messenger