title: [Synthetic peptide KKRR corresponding to the human ACTH fragment 15-18 is an antagonist of the ACTH receptor].
abstract: Tritium-labeled synthetic fragments of human adrenocorticotropic hormone (ACTH) [3H]ACTH (11-24) and [3H]ACTH (15-18) with a specific activity of 22 and 26 Ci/mmol, respectively, were obtained. It was found that [3H]ACTH (11-24) binds to membranes of the rat adrenal cortex with high affinity and high specificity (Kd 1.8 +/- 0.1 nM). Twenty nine fragments of ACTH (11-24) were synthesized, and their ability to inhibit the specific binding of [3H]ACTH (11-24) to adrenocortical membranes was investigated. The shortest active peptide was found to be an ACTH fragment (15-18) (KKRR) (Ki 2.3 +/- 0.2 nM), whose [3H] labeled derivative binds to rat adrenocortical membranes (Kd 2.1 +/- 0.1 nM) with a high affinity. The specific binding of [3H]ACTH-(15-18) was inhibited by 100% by unlabeled ACTH (11-24) (Ki 2.0 +/- 0.1 nM). ACTH (15-18) in the concentration range of 1-1000 nM did not affect the adenylate cyclase activity of adrenocortical membranes and, therefore, is an antagonist of the ACTH receptor.
authors: Iu A
authors: IuA
authors: Kovalitskaia
authors: A A
authors: AA
authors: Kolobov
authors: E A
authors: EA
authors: Kampe-Nemm
authors: V V
authors: VV
authors: Iurovskií
authors: V B
authors: VB
authors: Sadovnikov
authors: V M
authors: VM
authors: Lipkin
authors: E V
authors: EV
authors: Navolotskaia
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000302:Adrenal Cortex / Q000166:cytology / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018043:Receptors, Corticotropin / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D009842:Oligopeptides; D018043:Receptors, Corticotropin; D000324:Adrenocorticotropic Hormone; D000262:Adenylyl Cyclases