Partial characterization of a putative allatostatin receptor in the midgut of the cockroach Diploptera punctata.
Dippu-allatostatins (Dippu-ASTs) are a family of peptides originally isolated from the cockroach Diploptera punctata which appear to be pleiotropic in function. All members of the family are able to inhibit the biosynthesis of juvenile hormone by corpora allata in vitro. In addition, ASTs are able to modulate the contraction of visceral muscles and may play a role in the regulation of digestive enzyme secretion by the midgut. We have identified a putative AST receptor in the cockroach midgut using a radioligand-binding assay. (125)I-Dippu-AST 7 binding to midgut membranes was specific, saturable, and reversible. The midgut appears to contain a single class of binding sites for Dippu-AST 7, with K(d) of 20.9 +/- 3.6 nM and B(max) of 1.8 +/- 0.15 pmol. mg(-1) membrane protein. The relative affinity of the 13 members of the Dippu-AST family was determined using a single-point competitive binding assay. Dippu-AST 7 and 2 appear to have higher affinity for the midgut AST receptor than Dippu-AST 5, 9, 10, or 11. Other Dippu-ASTs were unable to compete with (125)I-Dippu-AST 7 for binding, even at high concentration.
Bowser
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PR
Department of Zoology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.
Tobe
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D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D003058:Cockroaches; D003335:Corpora Allata / Q000187:drug effects / Q000378:metabolism; D029721:Drosophila Proteins; D005260:Female; D006727:Hormone Antagonists / Q000494:pharmacology; D019476:Insect Proteins; D007413:Intestinal Mucosa / Q000378:metabolism; D007457:Iodine Radioisotopes; D007605:Juvenile Hormones / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D009479:Neuropeptides / Q000378:metabolism / Q000494:pharmacology; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000032:analysis* / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide
C096426:AstA-R1 protein, Drosophila; D029721:Drosophila Proteins; D006727:Hormone Antagonists; D019476:Insect Proteins; D007457:Iodine Radioisotopes; D007605:Juvenile Hormones; D009479:Neuropeptides; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide; C076523:allatostatin