[Molecular analysis of the human "growth hormone secretagogue"-receptor].
BACKGROUND
Growth hormone secretagogues (GHS) are highly potent synthetic peptides which release growth hormone (GH) by activation of a growth hormone-releasing hormone-independent signal cascade. A specific growth hormone secretagogue receptor (GHS-R) has been isolated, its endogenous ligand is still unknown. It might represent another major endocrine pathway controlling GH secretion. To gain insight into the specific function of the human GHS-R we studied the gene structure. Two variants, type 1a and 1b, have been described, but their specific functions are unknown.


RESULTS
A specific probe for the GHS-R was cloned following reverse transcription and PCR amplification of pituitary mRNA. A genomic human placenta library was screened for the GHS-R gene. Positive clones were identified and further characterized by Southern blotting and sequencing. A genomic clone of 18 kb in size was determined to include the coding sequence of both GHS-R variants. Here we show that GHS-R type 1a and type 1b are encoded by a single gene. Sequencing of the immediate 5'-flanking region suggests a number of transcription factor binding sites, but their functional significance remains to be investigated.


CONCLUSIONS
A genomic clone encoding for the two known variants of the human GHS-R was isolated. Further studies will determine physiological relevance and regulation of GHS-R. This will facilitate studies of GHS as diagnostic and therapeutic agents in GH disorders.
Petersenn
S
S
IHF Institut für Hormon- und Fortpflanzungsforschung, Universität Hamburg. petersenn@uke.uni-hamburg.de
Penshorn
M
M
Beil
F U
FU
Schulte
H M
HM
D019204:GTP-Binding Proteins / Q000235:genetics*; D006801:Humans; D011956:Receptors, Cell Surface / Q000235:genetics*; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D015183:Restriction Mapping
D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D019204:GTP-Binding Proteins
Molekulare Analyse des menschlichen "Growth Hormone Secretagogue"-Rezeptors.