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Query: UMLS:C1832588 (PSS)
 2,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent advances in the fields of molecular cloning and peptide purification necessitate a reappraisal of our views concerning the evolution of the genes encoding somatostatin-related peptides. The currently widely held view that the genomes of tetrapods contain only the preprosomatostatin-I (PSS-I) gene, encoding somatostatin-14, with a second preprosomatostatin gene being expressed only in teleost fish is no longer tenable. Identification of genes encoding both somatostatin-14 and the somatostatin-related peptide, cortistatin in mammals, identification of the PSS-I and PSS-II preprosomatostatin genes in amphibia, and the isolation of gene products from at least two non-allelic preprosomatostatin genes in lampreys suggests the alternative hypothesis that duplication of the PSS-I gene occurred early in evolution, predating or concomitant with the appearance of the chordates. We speculate that at least two somatostatin genes are expressed in all classes of vertebrates but these genes have evolved at very different rates. It is probable that the preprosomatostatin-II (PSS-II) gene, encoding [Tyr7, Gly10] somatostatin-14 or a related peptide, arose from a second independent duplication of the PSS-I gene in the ancestor of present-day teleost fish at a time after the divergence of the teleost stock from the line of evolution leading to tetrapods. The recent isolation of urotensin II, a peptide which contains a region of structural similarity but is not evolutionarily related to somatostatin-14, from the central nervous systems of lampreys, elasmobranchs and amphibia necessitates that we modify the accepted view that urotensin II is exclusively a product of the caudal neurosecretory system of teleost fish.
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PMID:Somatostatin- and urotensin II-related peptides: molecular diversity and evolutionary perspectives. 917 52

This study analyzes daily changes in the expression of somatostatin precursors PSS-I and PSS-III (structurally related to cortistatin) in the goldfish brain. The results indicate that PSS-I expression correlates with the light cycle only in optic tectum-thalamus (OT-Tha). PSS-III expression correlates with the light cycle in telencephalon-preoptic area (Tel-POA) and OT-Tha. In Tel-POA, PSS-III reaches a minimum level at the beginning of the active phase and a maximum level late in this phase. These results suggest that PSS-I in OT-Tha and PSS-III in Tel-POA and OT-Tha could be involved in the control of the activity cycles in goldfish.
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PMID:Pre-pro-somatostatin-III may have cortistatin-like functions in fish. 1589 Oct 36