title: A polymorphism in the growth hormone-releasing hormone receptor gene: clinical significance?
abstract: Two forms of the growth hormone-releasing hormone (GHRH) receptor (GHRH-R) exist in terms of a polymorphism at codon 57. The most common allele possesses GCG, coding for Ala. This codon can also be ACG, replacing the Ala with Thr. The present study demonstrates that the latter occurs in about 20% of pituitary somatotrophinomas, removed from patients with acromegaly. Somatotrophinomas possessing the alternative allele respond, on average, more strongly to GHRH in terms of GH secretion in vitro than tumors which are homozygous for the more common allele. The distribution of the two allelic forms of the GHRH-R did not significantly differ between acromegalic and non-acromegalic subjects. Thus, while the alternative allelic forms may, at least partially, contribute to the variable response of serum GH levels to i.v. GHRH observed in acromegalic and normal subjects, it is unlikely that subjects possessing the rarer form containing Thr in place of Ala at residue 57 are at increased risk of developing acromegaly.
authors.affiliation: Pharmaceutical Sciences Research Institute, Aston University, Aston Triangle, B4 7ET, Birmingham, UK. e.f.adams@aston.ac.uk
authors.forename: Eric F
authors.initials: EF
authors.lastname: Adams
authors.forename: Eftychia
authors.initials: E
authors.lastname: Oikonomou
authors.forename: Mandeep
authors.initials: M
authors.lastname: Bhamrah
authors.forename: Michael
authors.initials: M
authors.lastname: Buchfelder
authors.forename: Rosalind
authors.initials: R
authors.lastname: Mitchell
authors.forename: David R
authors.initials: DR
authors.lastname: Poyner
mesh_terms: D000172:Acromegaly / Q000235:genetics*; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000097:blood; D003062:Codon; D005091:Exons; D006801:Humans; D000860:Hypoxia / Q000235:genetics / Q000503:physiopathology*; D051379:Mice; D008815:Mice, Inbred Strains; D020641:Polymorphism, Single Nucleotide; D018013:Receptors, Neuropeptide / Q000235:genetics* / Q000502:physiology; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics* / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry; D012016:Reference Values; D014162:Transfection
chemical_list: D003062:Codon; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D011994:Recombinant Proteins; C048250:somatotropin releasing hormone receptor; D015740:Calcitonin Gene-Related Peptide