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Biomedical subjects

O N Savchenko

Publications and source records attributed to O N Savchenko.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Radioimmunologic analysis of steroids. Scientific and practical aspects].

Many-year experience of using authors' own systems for steroid radioimmunoassay (RIA) is summarized. Synthesis of natural and anabolic steroid derivatives and their conjugation with bovine serum albumin are considered. Schemes of rabbits immunization with steroid-protein conjugates, and the antisera characteristics are described. Data on comparison of 3H- and 125I-ligands in steroid RIA are presented as well as the characteristics of the RIA systems. The RIA optimization and quality control problems as well as the prospects of the RIA development are discussed.

Animals↗
PubMed1988

[Sexual dimorphism in the content of luliberin following deafferentation of the mediobasal hypothalamus].

Luliberin (LH-RH) was assayed radioimmmunologically in the hypothalamic fragments taken from male and female rats, intact or with isolated mediobasal hypothalamus. An increased amount of LH-RH was found in the fragments containing organum vasculosum of the lamina terminals (OVLT) and taken from intact males. LH-RH amount was negligible in isolated parts of hypothalamic fragments containing arquate nucleus of median eminence. OVLT of females was mu;ch richer with LH-RH than that of the males. The females though were characterized by a lower blood lutropin. The inhibitory influences on the secretion of LH-RH seem to be more obvious in intact males than in females.

Afferent Pathways↗
PubMed1987

[Effect of 5,6-hydroxytryptamine and various light schedules on the hypothalamo-hypophyseo-gonadal system of the female rat].

Hypothalamic luliberin and plasma lutropin concentration were studied under normal light-darkness cycle or under constant illumination in rats. Some of them were injected with 5,6-dihydroxytryptamine (5,6-HTA) into the lateral brain ventricle. Constant illumination led to a persistent oestrus with a significant drop in plasma lutropin and a decrease in hypothalamic luliberin. Destruction of serotoninergic terminals with 5,6-HTA resulted in an opposite effect and prevented to some extent inhibiting influence of constant illumination. Luliberin synthesis and secretion seem to be suppressed by serotoninergic nerve terminals on the luliberin producing cells as well as by serotonin reaching the hypothalamus from the pineal gland.

5,6-Dihydroxytryptamine↗
PubMed1986

[Changes in sexual functioning in the male rat after total or anterior deafferentation of the mediobasal hypothalamus].

After complete deafferentation of the mediobasal hypothalamus in male rats, the luteinizing hormone content increased in the blood which correlated with an increasing of testosterone secretion, weight of seminal glands and additional sexual organs. Half of the operated animals preserve copulating ability. The content of folliculo-stimulating hormone in the blood of animals after the complete deafferentation was decreased, particularly in non-copulating males. After the interior deafferentation of the mediobasal hypothalamus in the rats, the luteinizing hormone and testosterone contents in the blood did not change but the weight of seminal glands and concentration of folliculo-stimulating hormone in the blood decreased. The data obtained suggest different mechanisms of control of the luteinizing and folliculo-stimulating hormones secretion in male rats, the connection of the mediobasal hypothalamus with anterior hypothalamus and preoptic area being necessary for normal secretion of the folliculo-stimulating hormone.

Animals↗
PubMed1986

[The state of gametes and the type of maturation of follicular oocytes in rats neonatally androgenized by LH-RH-induced ovulation].

The character of follicular oocyte maturation and the state of gametes in androgenized rats was studied after LH-RH stimulation. The induction of ovulation with LH-RH has been shown to increase the number of rats with nonovulatory follicules and reduce the number of oocytes maturing prior to the onset of metaphase II. After the induction of ovulation the rate of chromosomal aberrations became higher than in intact animals. Ovulated oocyte population was characterized by the increased number of degenerated gametes. This increase was paralleled by decreased incidence of chromosomal aberrations in ovulated cells.

Animals↗
PubMed1983

[Effect of LH releasing hormone on the state of gametes and the maturation of follicular oocytes in vitro].

Ovulation, gametogenesis and maturation of rat follicular oocytes were examined in vitro under the effect of single and repeated injections of LH-RF. It was shown that LH-RF injection led to incomplete ovulation and to alteration of the heterogeneity of the gametes as regards the degree of maturation and the number of the degenerating forms. At the same time it did not produce any substantial effect on the rate of chromosomal abnormalities. The pattern of maturation of follicular oocytes from rats given LH-RH attests to the enhancement of atresia in the ovaries.

Animals↗
PubMed1983

[Effect of 6-hydroxydopamine and 5,6-Dihydroxytryptophan on the luliberin and luteinizing hormone levels in female rats under constant illumination].

Administration of 5,6-oxytryptophan to female rats' 3rd cerebral ventricle, as opposed to 6-oxydopamine, prevents the decrease in the luteinizing hormone contents in the blood occurring under constant illumination. Administration of 6-oxydopamine against the background of desmethylimipramine caused a significant increase of the luliberine contents in the anterior hypothalamus while preserving its normal level in the medio-basal portion.

5-Hydroxytryptophan↗
PubMed1983

[Estradiol receptors in the rat uterus under long-term hormone administration at different doses].

Multiple administration of estrogens in doses of 1 and 10 micrograms reduces specific binding of 3H-estradiol by subcellular fractions of rat uterus tissues. The cytoreceptor apparatus of the uterus of androgen-sterile rats is marked by the decreased response to a prolonged (7-8 days) hormone administration as compared to responses seen in normal and ovariectomized animals. The depletion of estrogen receptors is not linked with a rise of the endogenous steroid level in blood plasma and cytosol from uterine tissues.

Animals↗
PubMed1982

[The hypothalamo-hypophyseo-ovarian systems in rats after deafferentiation of the mediobasal hypothalamus].

Complete surgical deafferentation of the medio-basal hypothalamus (MBH) in rats entails suppression of the oestrus cycle as well as a decrease of luteinizing hormone, estrogens and progesterone release into the blood due to a sharp fall of the luliberine content in the median eminence and arquate nuclei. No connection was revealed between the character of oestrus disturbances and the extent of damage or isolation of the arquate, ventromedial, supraoptic and paraventricular nuclei and the amount of Homori-positive neurosecreted in the MBH. In development of permanent diestrus the MBH isolation was more complete than in the preservation of irregular cycle. The luliberine seems to be produced mainly in the anterior hypothalamus of rats whereas the MBH alone fails to maintain even its tonic secretion. Even in complete surgical isolation of the MBH, separate fibers of the luliberinergic cells penetrate into the MBH maintaining there a certain amount of luliberin and preserving synthesis of the luteinizing hormone in the hypophysis with its decreased release into the blood.

5-Hydroxytryptophan↗
PubMed1982

[Effect of stimulators of sexual function on the hypothalamo-hypophyseal system and the fertility of androgenized female rats].

Neonatal androgenization with 15--25 micrograms of testosterone-propyonate makes 43--54% of female rats sterile at puberty. Long-term administration of progesterone, clomiphen, luliberine, prostaglandin E2 induces ovulation but does not improve the fertility. Prostaglandin E2 decreases the amount of luliberine in the median emicnence and arquate nuclei within 30 min and increases the amount of luteinizing hormone in the blood of the control rats, whereas in the androgenized rats prostaglandin E2 is ineffective. According to the authors' hypothesis, a very mobile fraction of luliberine exists in the median emicnence, rapidly released into the portal blood system on stimulation and rather decreased in androgenization. Clomiphen increases the blood level of luteinizing hormone in the evening but its peak is twice as high in normal animals as compared with the androgenized ones.

Animals↗