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Biomedical subjects

V E Klusha

Publications and source records attributed to V E Klusha.

7 recordsLinked to original sources

[Studies of kinin-like properties of a new peptide isolated from bovine brain].

Kinin-like properties of two new peptides NRP-11 and P7 which have structural similarity with neurotensin (NT) and kallidin (K) were investigated. It was found that, unlike NT and K, the new peptides possess reduced myotropic and hypotensive activity. On the other hand, similarly to NT and K, the new peptides exhibited a high histamine-releasing activity in rat peritoneal mast cells. Possible central effects are implied for peptide NRP-11 isolated from bovine brain and its fragment P7.

Amino Acid Sequence

[Effect of some fragments of peptide hormones on the content of biogenic monoamines from mouse brain].

The effect of some tripeptides, which are fragments of peptide hormones, and their analogs on the content of biogenic monoamines (BM) from albino mice brain was studied. It was found that thyroliberin, melanostatin and the C-terminal tripeptide of gonadoliberin activate the dophaminergic (DA-ergic) system in the forebrain of mice treated with reserpine or haloperidol, whereas the C-terminal tripeptide of gastrin acts as a synergic blocker of the DA receptors. The N-terminal tripeptides (with and without the amido group) do not affect the content of BM. No effect of the tripeptides was observed in intact animals. It is assumed that the agonistic or antagonistic effect of the tripeptides on BM is due to certain structural peculiarities of the tripeptides, e.g. the presence of the C-terminal amido group and their endogenous nature.

Animals

[Comparison of structural and functional organization of adrenocorticotropic hormone and wasp kinin].

A comparative study of structural and functional organization of the polypeptides -- ACTH and wasp kinin was made. The effects of fragments Lys 17, 18-ACTH11(-18)-NH2--(I) and WK4(-12)--(II), possessing "common" fragments and a cluster of basic amino-acids, on the lipolytic and steroidogenic effects of ACTH and myotropic effects of bradykinin were studied. Both fragments I and II potentiate ACTH-induced lipolysis and steroidogenesis in isolated rat fat and adrenal cells but suppress the myotropic effect of bradykinin on guinea pig ileum. The similarity of biological effects of ACTH and WK fragments support our supposition on the similarity in structurally functional organization of these peptides.

Adipose Tissue

[Potentiation of ACTH action by a fragment of it: a decrease in the rat adrenal ascorbic acid concentration in vivo].

The effect of tripeptide NH2CO-Arg-Pro-Val-NH2, the analogue of common fragments of some peptide hormones and kinins, on the content of ascorbic acid in rat adrenal glands in vivo is studied. It is shown that the peptide (5 divided by 3000 mkg/100 g body weight) produces no effect on the content of ascorbic acid in adrenal glands, but its injection half an hour before the administration of native ACTH canses a significant increase in the ACTH activity. The peptide possesses the myotropic activity; it exerts sinergism and potentiation of the ACTH action on rat ascending colon.

Adrenal Glands

[Use of specific angiotensin inhibitors in the study of hormone-receptor interaction].

The specificity of receptors participating in the interaction with angiotensin II (AT 1--8) fragments, e. g. N-terminal tri-(AT 1--3), C-terminal penta-(AT 4--8), and middle tetrapeptide (at 3--6), was studied in experiments on rat ascending colon which were performed to investigate the influence of a specific angiotensin antagonist, /1-hydantoic acid, 5-valine, 8-alanine/-angiotensin (HAAT 1--8), on myotropic effects of these fragments as well as the influence of the fragments on the myotropic activity of the whole hormone molecule. Competitive antagonism was found between HAAT 1--8 and AT 4--8 and AT 3--6 and between these fragments and AT 1--8. No antagonisma was revealed between AT 1--3 and HAAT 1--8, and between AT 1--3 and AT 1--8. It is assumed that the fragments AT 4--8 and AT 3--6 interact at the level of angiotensin receptors, and that of AT 1--3 at the level of non-specific receptors. A new model for the structural and functional organization of angiotensin is proposed.

Angiotensin II

[Specific antagonism between angiotensin II and several of its analogs].

The authors studied comparatively the properties of two angiotensin II analogues, a new compound (1-hydantoin acid, 5-valine, 8-alanine)-angiotensin II (compound III) and (1-asparagine, 5-valine, 8-alanine)-angiotensin II (compound II), as of the myotropic action of angiotensinamide (these experiments were conducted on the rat isolated ascending colon); pressor action of the hormone was investigated in experiments on anesthetized rats. A competitive character of the antagonism--within the range of low concentrations of the analogues--10(-10)--10(-9) M/l--was revealed in vitro. No antagonism was expressed against the nonspecific myotropic agents--acetylcholine and bradykinin. In vivo compounds II and II manifested the antagonistic action against angiotensinamide beginning from the doses of 100 and 50 gamma/kg, respectively.

Angiotensin II