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Biomedical subjects

N A Iudaev

Publications and source records attributed to N A Iudaev.

At least 19 recordsLinked to original sources
PubMed1982

[Amino acid sequence of seiwhale somatotropin].

Thirteen homogenous peptides were isolated from the chymotryptic hydrolysate of seiwhale somatotropin. The amino acid composition and sequence of the chymotryptic peptides were determined. Two large peptides were isolated from the tryptic hydrolysate of the performic acid-oxidized somatotropin. One of them had 20 amino acid residues and contained cysteic acid; the other one consisted of 31 residues and contained tryptophane and numerous leucine residues. The amino acid sequence of tryptic peptides was established after their hydrolysis with chymotrypsin. Based on these and earlier published data a complete amino acid sequence of seiwhale somatotropin comprising 190 amino acid residues was proposed. O comparison of primary structure of somatotropins from 6 different sources revealed the most conservative and variable regions of the hormone polypeptide chain.

Amino Acid Sequence↗
PubMed1981

[Adenylate cyclase activity and cyclic nucleotide content in human adrenal tumors under Icenko-Cushing syndrome].

The adenylate cyclase activity and cyclic nucleotide content in excised human adrenal tumours (Icenko-Cushing syndrome) were determined. The experimental data were compared to those obtained for hyperplastic adrenals. All adrenal tumours under study revealed a decreased cAMP level, an increased cGMP level and a resulting decrease of the cAMP/cGMP ratio. In malignant adrenal tumours the adenylate cyclase activity was sharply increased in comparison with that in hyperplastic adrenals. In the majority of malignant tumours the adenylate cyclase response to ACTH was either altogether absent or sharply decreased. In benign adrenal tumours the basal activity of the enzyme was unchanged and the enzyme response to ACTH was essentially normal. The decrease of adenylate cyclase response to ACTH in malignant tumours is apparently not due to the impaired catalytic activity of the enzyme, since its response to stimulation by sodium fluoride remains unaffected. In some tumours (one malignant and two benign ones) a non-specific stimulation of adenylate cyclase by hormones, which are not natural activators of the enzyme was observed. It was assumed that these changes are due to the damage of hormonal receptors in adrenal tumours.

Adenylyl Cyclases↗
PubMed1980

[Prostaglandin regulation of the sex hormone receptor content in human decidual tissue].

Prostaglandin F2 alpha (PGF2 alpha) and its synthetic analog, 15-methyl-PGF2 alpha effects on the receptor content of estrogens and progesterone in the human decidual tissue were studied in vitro and in vivo experiments. The receptor content in vivo experiments was determined by Sketchard's technique and in vitro by the saturation method. Three hours after intravaginal administration of 15-methyl-PGF2 alpha suppositories to pregnant women the level of estrogen and progesterone receptors in decidual tissue cytosol significantly increased. Affinity of receptors with hormones remained unchanged. 10, 20, 50 and 100 mcg/ml concentrations of PGF2 alpha produced a significant and dose-dependent increase in the receptor content of estrogens following 15, 30, 60 and 180 minutes incubation of decidual tissue sections. The receptor level of progesterone remained unchanged. In experiments with inhibitors of protein and RNA biosynthesis, it was shown that an augmentation of the estrogen receptor content under PGF2 alpha action is not associated with biosynthesis of receptors de novo.

Abortion, Induced↗
PubMed1979

[Lipolytic effects of a synthetic tetradecapeptide, corresponding to 31-44 amino acid sequence of human somatotropin].

A synthetic tetradecapeptide 31--44 developed a fast lipolytic effect in rats and rabbits in vivo and in vitro. The concentration of plasma fatty acid was maximal after 30 min following the injection and came down to the initial level after 60--120 min. The effect was prolonged when the tetradecapeptide was injected in the form of Zn-suspension. Both in rats and rabbits the in vivo lipolytic effect of native somatotropin was pronounced only after a 2-hr latency. Actinomycin D and cycloheximide did not prevent the lipolytic effect of the tetradecapeptide in isolated adipose tissue; however, this effect was not exerted in the absence of Ca2+. The hexapeptide fragment of tetradecapeptide was inactive in rats in vivo, but had a slight effect an isolated rat adipose tissue when taken at high doses. Thus, the lipolytic effect of the tetradecapeptide requires Ca2+ and is more pronounced in rabbits than in rats. Contrary to somatotropin, the effect of tetradecapeptide is fast and independent of RNA and protein synthesis. These data and previously shown tetradecapeptide lipolytic effect on isolated human adipose tissue suggest that the tetradecapeptide possesses structural features required for the lipolytic effect of the whole hormone.

Adipose Tissue↗
PubMed1976

[Effect of synthetic tetradecapeptide corresponding to 31-44 amino acid sequence of growth hormone on lipolysis in human adipose tissue].

Fat mobilyzing activity of synthetic tetradecapeptide, which corresponds in 31--44 amino acid sequence of human growth hormone, is studied in vitro in human fat tissue. The peptide at concentrations of 3--33 microng/ml considerably stimulated lipolysis in subdermal fat tissue, omentum and shoulder ateroma. Minimal efficient peptide concentration was 3 microng/ml in most experiments, sometimes it was 0.3 microng/ml. Direct dependency between dose logarithm and lipolysis rate was observed at dose interval of 0.3--18 microng/ml. Native growth hormone produced no activity in human fat tissue even in concentrations of 50--100 microng/ml.

Adipose Tissue↗