title: Molecular evolution of growth hormone and receptor in the guinea-pig, a mammal unresponsive to growth hormone.
abstract: Growth in the guinea-pig is completely unresponsive to endogenous or exogenous growth hormone, despite the fact that the guinea-pig produces normal to high levels of growth hormone and receptor. In primates and artiodactyls, growth hormone exhibits accelerated rates of evolution that appear to be correlated with changes in function. Surprisingly, both guinea-pig growth hormone and receptor exhibit slow rates of evolution similar to those seen in other mammals, implying that both proteins are as functionally conserved in the guinea-pig as in other mammals or that any loss or relaxation of functional constraint was very recent. However, the guinea-pig growth hormone and receptor both exhibit a single amino acid replacement at a site known to have functional significance. Nevertheless, it is unclear whether the aberrant nature of the guinea-pig growth hormone-growth hormone receptor axis is due to these replacements or whether it is due to a defect in post-receptor signalling.
authors.affiliation: Biology Department, 219 Morrill Science Center, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Adkins
authors.forename: J
authors.initials: J
authors.lastname: Vandeberg
authors.forename: W H
authors.initials: WH
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D013006:Growth Hormone / Q000235:genetics* / Q000494:pharmacology / Q000502:physiology; D006168:Guinea Pigs; D008969:Molecular Sequence Data; D011986:Receptors, Somatotropin / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D011986:Receptors, Somatotropin; D013006:Growth Hormone