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Biomedical subjects

A A Bulatov

Publications and source records attributed to A A Bulatov.

At least 19 recordsLinked to original sources
PubMed1998

A mutational hot spot in the Prop-1 gene in Russian children with combined pituitary hormone deficiency.

Combined pituitary hormone deficiency (CPHD), including growth hormone (GH), prolactin (Prl) and thyroid-stimulating hormone (TSH) in children is now considered a heterogeneous syndrome. Recent findings on expression of mouse pituitary-specific homeodomain factors demonstrate dependence of adenopituitary ontogeny on interactive expression of these factors, suggesting their involvement in etiology of CPHD. Prophet of Pit-1 (Prop-1) gene, a novel pituitary-specific homeodomain factor, was analyzed in 14 Russian children with CPHD, in whom Pit-1 gene was intact. We found a mutational hot spot in three patients from two families in homeodomain part of the second exon of Prop-1 gene. The common 2-base pair deletion (GA296) in the homozygous state resulted in a Serine to Stop codon (S109X) substitution and generated a truncated Prop-1 protein. Parents were phenotypically normal and heterozygous for GA296 deletion, indicating an autosomal recessive inheritance. These results demonstrate a novel type of Prop-1 gene mutation as one of the causes of CPHD in Russian patients.

Amino Acid Sequence↗
PubMed1998

Compound heterozygous deletion of the PROP-1 gene in children with combined pituitary hormone deficiency.

Mutations in the prophet of Pit-1 gene (PROP1) have been shown to be responsible for combined pituitary hormone deficiency (CPHD) with deficiencies of growth hormone (GH), Prolactin (Prl), thyroid-stimulating hormone (TSH) and gonadotropins. We previously reported that homozygosity for a 2bp deletion in exon 2 (296delGA) accounted for CPHD in three patients from two Russian families. Here we report a second mutational hot spot in exon 2. This 2bp 149delGA deletion results in a frame shift that leads to the same serine to stop codon change at codon 109 (S109X). The predicted proteins are each truncated at residue 108 but diverge from the wild type sequence at different points in the homeodomain. Compound heterozygosity for the two mutations (149delGA/296delGA) was detected in 5 of 14 CPHD children from 4 families (36%). This provides the first evidence of heterozygosity for two common deletions as a cause of CPHD in Russian children.

Adolescent↗
PubMed1997

Biochemical nature of high-molecular-weight prolactin of human serum: identification of a prolactin-binding protein.

The biochemical nature of a high-molecular-weight immunoreactive prolactin (HMW-irPRL) prepared by gel filtration of women's sera with predominance of this hormone form was studied. Immunochemical characteristics of HMW-irPRL are different from those of 23 kD prolactin (23 kD-PRL). A protein which specifically and reversibly binds to human [125I]PRL is isolated from the pooled fractions of HMW-irPRL by affinity chromatography on prolactin-Sepharose. According to gel filtration, the binding protein (BP) has molecular weight about 150 kD, and it reversibly binds to protein A immobilized on Sepharose. Analysis of BP by SDS-PAGE resulted in two major protein bands, of 65-70 and approximately 150 kD. Both the bands, when transferred to nitrocellulose, interacted with [125I]protein A. Binding of highly purified human pituitary prolactin to the BP significantly decreased the immunoreactivity of the hormone. The molecular weight of BP and its interaction with protein A and recognition by poly- and monoclonal antibodies against human (but not guinea pig) IgG indicate that BP may be an immunoglobulin. Thus, our data demonstrate that HMW-irPRL is formed by the binding of 23 kD-PRL to a specific serum protein which is probably an anti-prolactin IgG.

Adsorption↗
PubMed1995

Growth hormone (GH)-releasing effects of synthetic peptide GH-releasing peptide-2 and GH-releasing hormone (1-29NH2) in children with GH insufficiency and idiopathic short stature.

To investigate how growth hormone (GH)-releasing peptide (GHRP) and GH-releasing hormone (GHRH) interact in patients with short stature, we examined the acute effects of GHRH1-29NH2, GHRP-2, and the combination of GHRH1-29NH2 and GHRP-2 on GH release in children with GH insufficiency ([GHI] group A) and idiopathic short stature ([ISS] group B). Ten children with GHI (aged 11.8 +/- 1.1 years; height, -4.2 +/- 0.5 SDS) and five children with ISS (aged 11.1 +/- 1.2 years; height, -3.2 +/- 0.1 SDS) were studied. Intravenous bolus infusions of GHRH1-29NH2 (1 micrograms/kg), GHRP-2(1 microgram/kg), and GHRH plus GHRP-2 (each 1 micrograms/kg), were administered in a randomized order. Because of the variability of GH responses, results were analyzed by a nonparametric statistical method. Patients in group A showed low GH responses to both GHRH1-29NH2 and GHRP-2 stimulation: in only three of 10 and one of nine cases, respectively, were the peak GH levels above 5.0 micrograms/L. GH area under the curve (AUC) 90 minutes after GHRP-2 administration was slightly less than for GHRH1-29NH2 (179 +/- 150 v 214 +/- 68 micrograms/L.min, P = .06). In group B, GH responses to GHRH1-29NH2 and GHRP-2 were approximately of the same magnitude (1,943 +/- 819 v 1,981 +/- 887 micrograms/L.min, P = .9).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Molecular forms of human growth hormone and prolactin, secreted by cultured pituitary tumor cells].

Functionally active cultures of human pituitary adenoma cells producing excessive amounts of the growth hormone (somatotropinomas), of prolactin (prolactinomas) or of the both hormones (mixed type adenomas) have been prepared and their secreted molecular forms studied. SDS-PAAG electrophoresis combined with immunoblotting making use of poly- and monoclonal antibodies revealed that the growth hormone and prolactin are secreted by adenoma cells in several molecular forms typical of normal human pituitary. The major form secreted by the growth hormone is 22K; the minor forms are 20K (the product of alternative splicing of pre-mRNA) and the split-off two-chain form 25K. The major form secreted by prolactin is 23K; the minor form is glycosylated 25K. No significant differences in the ratios of molecular forms of the hormones were found either under basal conditions of culturing or under the influence of the pituitary function regulators, somatostatin and thyroliberin. At the same time, the data obtained suggest that pituitary adenoma cells can secrete some amount of "abnormal" molecular forms of the hormones, e.g., immature products of postribosomal processing or large-sized immunoreactive fragments. Hence, pituitary adenoma cell cultures are an effective tool in biochemical and physiological studies of molecular forms of the human growth hormone and prolactin and of their secretion.

Adenoma↗
PubMed1992

[An electrophoretic analysis of human glycoprotein hormones and their subunits].

Stability of heterodimers of human glycoprotein hormones with gonadotropic and thyrotropic activities in sodium dodecylsulfate (SDS) under non-reducing conditions at low temperature permits to resolve the native molecules of these hormones in SDS-PAG and to distinguish from their dissociated subunits by electrophoretical mobility. The analysis of dimers and alpha-, beta-subunits in one polyacrylamide gel allows to detect certain human glycoprotein hormones and to study some of their physico-chemical properties. Using two polyclonal antisera against human LH and FSH by the Western blot immunoassay it was shown that heterodimers as well as alpha and beta subunits after SDS-PAGE retain antigenic activity of native hormones. The method gave possibility to characterize the specificity of the given sera to different glycoprotein hormones.

Animals↗
PubMed1992

[Regulation of hormone secretion in primary cell cultures of human somatotropinomas].

The effects of somatostatin and thyroliberin (thyrotropin-releasing hormone; TRH) on growth hormone (GH) and prolactin (PRL) secretion were studied in short-term (0.5-3h) or long-term (21-24h) incubations using monolayer cell cultures of somatotropin obtained from surgical material of patients with acromegaly. High sensitivity of both GH and PRL release to inhibitory action of somatostatin (10(-11) M) was established. We could not reveal the unambiguous influence of TRH on somatotropic function in the in vivo and in vitro conditions, as compared to the action of this tripeptide on PRL secretion. The results obtained permit us to propose that cell cultures of pituitary adenomata represent adequate and convenient models for studying the pathogenesis of tumor processes in the pituitary gland and for the development of new procedures of pharmacotherapy.

Acromegaly↗
PubMed1992

[Obtaining and morphological characteristics of primary monolayer cell cultures of human somatotropinomas].

This paper describes the development of method of preparing cell suspension obtained from surgical material of patients with pituitary adenomas and acromegaly as well as the procedure of subsequent long-term cultivation in monolayers of the cells isolated. As judged by visual inspection and measurement of growth hormone and prolactin secretion, tumor pituitary cells kept viability and functional activity for at least 6 days of growing in vitro. Immunocytochemical visualization of somato- and lactotrophs of the same histological preparations permitted us to show that vast majority of cultured cells is represented by somatotrophs; however, a small portion of cell population is represented by lactotrophs and lactosomatotrophs. The peculiarities of cytoarchitectonics in two types of cell cultures of human somatotropinomas were studied.

Acromegaly↗
PubMed1991

[The interaction of growth hormone secretion and gonadal function in adolescents with delayed physical development].

The studies conducted in adolescents with physical underdevelopment allowed a conclusion on reduced anabolic processes particularly growth process at the expense of both STH and sex steroids: T and E2. Studies of sex steroid and gonadotrophic hormone concentrations in blood serum revealed dysfunction of the hypothalamo-hypophyseal-gonadal system in this group of patients. Evaluation of androgen receptor level in protein cytosol fraction from the pubic skin of undersized youths with delayed sexual development demonstrated its significant reduction against the control group that may be explained by incomplete ability for androgen receptor synthesis due to relatively low T-level and its biologically active free fraction and low sensitivity of target tissues to androgens as a result of dissociation between functional activity of STH and T.

Adolescent↗
PubMed1989

[Obtaining of monoclonal antibodies to human growth hormone and their characteristics].

The aim of present study was to obtain the hybridomas producing monoclonal antibodies against human growth hormone (Mabs hGH), to investigate the properties of the obtained Mabs and the possibility of their application in immunoanalytical systems. Two hybridomas secreting Mabs against hGH and belonging to the IgGI subclass have been obtained. The cross-reactivity of the Mabs with structurally similar to hGH hormones (hGHbio, hPL, hPRL, bGH, bPRL, pPRL) using indirect IFA has been studied. It has been shown that Mabs hGHI and Mabs hGH2 are directed to common specific antigenic determinant i.e. they have the same epitope specificity and don't react with other structurally related hormones, i.-e. this determinant is unique for hGH. The obtained Mabs hGH2 would find application for determination hGH by immunochemical methods in fractions while the hormone isolation from pituitaries and hGH obtained recombinant DNA methodology. The development of immunosorbents on the basis Mabs hGH2 seems to be perspective. Application of this immunosorbent may give possibility to optimize hormone isolation process.

Animals↗
PubMed1984

[Possible role of somatotropic hormone in regulating the functional state of glial cells in the central nervous system].

Experiments were made to study the actions of STH and its fragment capable to stimulate the growth processes on MAO activity and selective binding of catecholamines by alpha- and beta-adrenoreceptors in glial cells of the rat brain cortex. For comparison the effects of STH and its fragment on 3H-PGE1 binding were studied. STH and its fragment were found to produce no influence on MAO activity or specific binding of 3H-PGE1 with glial cells. STH and its fragment (5.10(-9) M) were found to reduce specific binding of 3H-dihydroergocryptine with beta- and alpha-adrenoreceptors of glial cells, respectively. It is suggested that STH and its fragment can modulate the function of glial cells by changing the selective action of catecholamines on subpopulations of adrenergic receptors.

Alprostadil↗
PubMed1983

[New data on the biological activity of pituitary somatotropin fragment 77-107].

Some new evidence on the biological activity of somatotropin fragment 77-107 is given. This fragment was prepared from whale somatotropin by tryptic hydrolysis. Beside the previously established ability of the hormone to increase the width of the tibial epiphyseal cartilage in hypophysectomized rats ("tibia" test) two other properties of the fragment indicative of its growth-promoting activity were established. The fragment enhances DNA biosynthesis in cultured human fibroblasts and increases the somatomedin content in blood serum of hypophysectomized rats. However, the fragment unlike the native hormone does not exert any metabolic action on adipose tissue "in vitro", i. e. does not stimulate the nonesterified fatty acid release into the medium. A comparison of the biological activity spectrum of native somatotropin and of its fragment 77-107 suggests that the biochemical information required for the realization of a prolonged growth-promoting effect and a relatively rapid action of the hormone on lipid and carbohydrate metabolism is contained in different parts of the polypeptide chain.

Animals↗
PubMed1982

Primary structure of seiwhale pituitary somatotropin.

Seiwhale somatotropin has been isolated from seiwhale pituitaries. It was cleaved by cyanogen bromide, trypsin and chymotrypsin. The peptide fragments were separated and purified by gel filtration on Sephadexes, ion exchange chromatography, high voltage electrophoresis and paper chromatography. Amino acid sequences of the isolated peptides were studied by the dansyl-Edman procedure. The data obtained suggested a primary structure of seiwhale somatotropin consisting of 190 amino acid residues and showed a high degree of homology with somatotropins of many other species.

Amino Acid Sequence↗