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Biomedical subjects

N A Karpenko

Publications and source records attributed to N A Karpenko.

12 recordsLinked to original sources
PubMed1990

[Male sexual behavior in thyroxine toxicosis].

A shortening of mounting latency and postejaculatory period revealed an activation of sexual behaviour's motivational components in thyroxin toxicosis in male rats. A negative correlation was found between the postejaculatory period duration and the thyroxin level. The estradiol concentration increased whereas the testosterone one decreased in rats and was followed by a lowering of ejaculations in the test. The serotonin contribution to the mechanism of activation of sexual behaviour's motivational component in thyroxin toxicosis, is discussed.

Animals↗
PubMed1986

[Physiologic basis for the "attractiveness" of female rats for males].

Sexual behaviour of intact male rats was studied in tests with ovariectomized female rats and with those injected with sexual hormones. The data obtained support the hypothesis of the existence of central and peripheral mechanisms regulating the sexual behaviour of male rats. The treatment of castrated females with androgen resulted in males sniffing at them mor often, the copulatory behaviour being only observed in tests with females treated with estrogens in combination with progesterone.

Animals↗
PubMedDate not supplied

[Sexual function of male rats exposed to the factors of the Chernobyl exclusion zone].

The influence of chronic internal and external irradiation in low doses on sexual behavior and fertility of sexual active animals keeping within the 30-km Chernobyl exclusion zone was studied. After the 1.5 month consumption of drinking water containing radionuclides of natural Chernobyl spectrum the decrease in proportion of sexual active animals and suppression of sexual motivation and erection were observed. This deviations resulted in the reducing of the inseminated females number. The dependence between the magnitude of total absorbed dose and the working of the sexual behavior regulative mechanisms was obtained. In addition, the reduction of rat fertility took place because of the increase of preimplantation, but not post-implantation death in in irradiated females coupled with irradiated males. The irradiation of males with total absorbed dose on testis 0.23 cGy decreased the fertility because of sexual behavior disturbance, and this effect was intensified by negative influence of ionizing radiation in the range of 0.7-7.0 cGy on male gametes.

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PubMedDate not supplied

[The effect of grofollon on the induction of sex maturation in female rats].

The authors provide the results of experimental studies carried out in immature female rats given the gonadotropin grofollon to stimulate puberty. Grofollon was administered in doses of 20, 30 or 50 units. It was dissolved in a physiological solution or prolongon. The effect of grofollon was found to depend on the dose and type of the solvent. The earliest response (in 6 hours) to grofollon administration was marked by an increase of plasma estradiol. 24 hours after the hormonal treatment there was a rise of the mass of the ovaries and uterus, in particular. The vagina opened on the 3d day. The dissolution of grofollon in prolongon was discovered to enhance the drug efficacy.

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PubMedDate not supplied

[Estimation of long-time effects of Chernobyl AES accident on behavior markers in a small rodent population].

Differences in behaviour reactions in "open field" and glycemia under conditions of immobilisation stress of vole (Microtus oeconomus, Pallas) from two groups ("Yanov" and "Lelev") were investigated. Rodents were ensnared from two populations reproduced for a long time (11 years) in the areas of ChNPP Exclusion Zone with different level of radioactive contamination. The radiation absorbed dose for animals of "Yanov" group (external and internal irradiation) was 11-20 times higher than that of "Lelev" group. Males and females from the area with worse radioecological condition had higher vertical and horizontal locomotion. The level of emotional reactions of "Yanov" males was lower than the "Lelev" one. Statistically significant variation in female emotional reaction was found, but it had not the same directions. In both groups higher locomotion activity and lower emotionality were associated with male sex. The males of both groups showed similar fasting glucose level and glycemic response after 30-min. immobilisation. Our data provide the additional evidence of existence of long-time genetic effects in small rodent populations permanently reproduced on radiation contaminated areas.

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PubMedDate not supplied

[The effect of testosterone and its metabolite dihydrotestosterone on the hormone level of hypothyroid rats].

The levels of thyroid and sex hormones, TSH and PRL were studied in thyroidectomized (6 weeks) noncastrated rats and in castrated rats receiving testosterone propionate (1 mg/kg) or dehydrotestosterone (0.2 mg/kg) or their mixture to reveal the hormonal nature of disorder of sexual function in hypothyrosis. The results obtained show that all disorders of sex function in hypothyroid rats with a different androgenic status have a different hormonal basis.

Animals↗
PubMedDate not supplied

[Interrelationship of thyroid and sex functions in males].

The purpose of this experiment was to study on intact and castrated male rats the aftereffects of administration of different androgens for thyroid function as well as the effect of experimental thyrotoxin toxicosis on sex gland incretion and the hormonal status of castrated animals receiving substitution androgenic therapy. The level of hormones was determined by a radioimmunoassay: Castration was shown to be accompanied by suppression of thyroid function, and the administration of androgens activated it. Aromatized testosterone (but not non-aromatized dehydrotestosterone) enhanced thyroxin transformation into T3 and prevented castration-induced estrogenization. Hyperthyroxinemia in castrated animals was accompanied by an increase in progesterone and estradiol concentrations. Hyperestrogenization increased with a parallel administration of androgen. Negative correlation between TSH and sex hormones levels was noted. During thyroxin toxicosis sex hormones served as modulators of hypophyseo-thyroid relationships.

Animals↗
PubMedDate not supplied

[Effect of testosterone and dihydrotestosterone on the sexual behavior of female rats].

Sexual behaviour was tested in female rats with ovariectomy treated with various sexual hormones and healthy male rats with sexual experience. There was a marked suppression of receptive behaviour in rats with ovariectomy but the proceptive one was preserved. A marked growth of lordosis, achieving the level of that in intact rats in estrus is observed after the administration of estradiol propionate (10 micrograms) and progesterone (500 micrograms). A single subcutaneous administration of testosterone dipropionate (100 micrograms) and dihydrotestosterone (DHT) with DHT-propionate (10 micrograms) to ovariectomized rats did not stimulate lordosis but preserved a high level of proceptive behaviour. Disconnections in the character of proceptive and mating behaviour show that different mechanisms are in the base of their regulation. No difference was noted in the effect of testosterone and DHT on sexual behaviour. The administration of DHT induced certain aggressiveness in the animals. No dynamics was observed in the character of the studied indicators for 3 days. The lack of differences in testosterone and DHT action on sexual behaviour of female rats shows that intracerebral aromatization is not obligatory for the manifestation of the effect.

Animals↗
PubMedDate not supplied

[The trends and intensity of lipid peroxidation processes initiated by the action of "Chernobyl" factors].

The 45-day's action of nutritional radionuclides (137Cs, 90Sr, 40K) by inside organism irradiation at doses: 0.16 sGy, 0.55 cGy, 5.5 cGy was investigated. The blood, muscles, heart, kidneys, lung, liver, brain, spleen and testis were studied. The content of dienes, trienes, oxodienes, tetraenes conjugates and malondialdehyde were researched. The level of dienes increased in blood and kidneys; MDA--in spleen than more, that more of dose irradiation. Content of oxodienes, trienes and tetraenes (the biological activity eicosanoids) decreased at kidneys, lung, brain and spleen. At total, these parameters by organism's adaptational systems controlled at physiological conditions.

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