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Biomedical subjects

V N Demchenko

Publications and source records attributed to V N Demchenko.

At least 19 recordsLinked to original sources
PubMed1987

[Cessation of ovarian cycles in a young mouse while in parabiosis with an older one].

Female mice 3 and 22-24 months of age were jointed in heterochronic parabiosis. That led to permanent estrus in young mice and maintenance of intact anestrus in old mice. After 8-9 weeks of parabiosis there appeared morphological signs of accelerated ageing in the ovaries of young animals, while no changes in the ovaries of old mice were observed. Serum progesterone of young partners decreased to the levels of old animals and estradiol levels remained unchanged, while prolactin content in adenohypophysis was the same as in young single animals but exceeded the level noted in young mice in parabiosis with young partners. Hormone content in old parabionts remained unchanged, as compared to the control. An old organism is thought to be the source of unidentified factors suppressing the ovarian function in young animals.

Aging↗
PubMed1986

[Functional state of the hypophysis and ovaries of rats with anovulatory syndrome during pharmacologic stimulation of dopaminergic receptors].

Pharmacological analysis of the role of hyperprolactinemia in the pathogenesis of anovulatory syndrome (AS) was performed in neonatally androgenized rats. Dopamine agonist, bromocriptine, administered to I or 2.5 month-old rats for 15 days decreased prolactin content in the adenohypophysis and partially normalized progesterone level in blood plasma. However, bromocriptine failed to prevent the development of AS or to interrupt persistent estrus in neonatally androgenized females. The results are in keeping with the concept on the leading role of hypothalamus noradrenergic insufficiency in the pathogenesis of experimental AS.

Animals↗
PubMed1979

[Change in the dependence of lymphocyte reactivity to phytomitogens on endogenous hormonal factors in experimental bacterial lesion of the prostate].

The relationship between the blast lymphocyte transformation response (BLTR) to PHA P, Con A, PWM and 11-hydroxycorticosteroids (I) and the testosterone (II) levels in the blood plasma and the excretion of 17-ketosteroids with the urine were studied in 11 dogs with experimental urogenous prostatitis, provoked by Staphylococcus aureus, isolated from a patient with chronic prostatitis. Multiple correlation between the BLTR and hormonal factors was noted before the experiment. It was disturbed in a month and restored 2 months after the beginning of the experiment. Before the studies the relationships were mainly realized by direct correlation with 1 and 2 months after the experiment--due to the negative correlation with II. A homeostatic nature of the hormone lymphoid relationship with respect to 11-hydroxy-corticosteroids is suggested.

Androgens↗
PubMed1978

Hypothalamo-hypophyseal-gonadal system in male rats and guinea pigs treated with the antiandrogen 4-nitro-3-trifluoromethylisobutyranilide.

Influence of the competitive testosterone antagonist 4-nitro-3-trifluoromethylisobutyranilide (NFBA) on the hypothalamo-hypophyseal-gonadal system in male Wistar rats and guinea pigs was studied. NFBA as well as nonlabelled testosterone diminished 3H-testosterone uptake in hypothalamus and hypophysis of castrated animals. Increase of plasma testosterone level was obtained after the antiandrogen treatment in a dose of 10 or 25 mg/kg per os during 3, 10 and 48 days. Maximal level of the hormone was noticed on the 10th day. The contents of 17-ketosteroids in testes had not changed, but the testosterone content and steroid-delta5-3beta-ol-dehydrogenase activity were high during the treatment period. After 10 days of NFBA administration increased plasma LH level was found. Increase in size and number of gonadotropocytes was revealed by histological and histochemical methods as well as Leydig cell hypertrophy. High plasma testosterone level and Leydig cell activation were obtained in guinea pigs as a result of NFBA subcutaneous injections in a dose of 10 mg/kg during 30 days. The suggestion is made that prolonged NFBA treatment produces changes in the testosterone metabolism. Short-term administration of NFBA may be used for the estimation of the hypothalamo-hypophyseal functional abilities.

Anilides↗
PubMedDate not supplied

[The immune response to heteroantigen of male mice at various stages of ontogeny and following gonadectomy].

Experiments on male CBA mice have shown that androgens modulate the function of the immune system depending on its initial functional status. Studies of humoral immune response in mice during ontogeny have revealed that the most pronounced activation of the immune system coincides with the beginning of the sexual maturation (18-30 days). Gonadectomy of 18-days-old mice causes retardation of the functional maturation of the immune system but that of 1 month-old mice, on the contrary, intensifies the immune response. It is supposed that this period of life is one of the key periods of the humoral immunity development. Long-term decrease of the testosterone level in blood of mice castrated after puberty induces untimely extinction of the immune reactivity comparable with that in old animals.

Animals↗
PubMedDate not supplied

[Testosterone content of the blood plasma in mature animals of various species during modeling of a pathological process in the testes using testicular antibodies].

Testosterone content in the blood plasma before and after administration of testicular antibodies (IgG and IgM) isolated from respective antisera was studied by a radioimmunoassay in 86 mature mice, rats and guinea-pigs. IgG at a dose of 0.4-2.4 mg of protein per 100 g of body mass decreased testosterone content in the blood plasma 1.6-4.2-fold early after administration (on the 3rd-6th day) in animals of all species. The level of testosterone remained below the basal values in the course of 33 days after the administration of immunoglobulins. A single administration of IgG at a dose of 2.4 mg of the protein resulted in a less damaging effect on the animals' testes than the same amount of the protein administered in fractions (at a dose of 0.8 mg three times a day). IgG produced a higher inhibiting effect than IgM administered at the same doses. Immunoglobulins of class G isolated from antisera which are specific to the testicular tissue, can be used for the simulation of a pathological process in the testes for a study of the etiology and pathogenesis of hypogonadism which is quite frequent in clinical practice.

Animals↗
PubMedDate not supplied

[Use of the antiandrogen niftolide for studying reserves of the hypothalamo-hypophyseal system in patients with male hypogonadism].

A study was made of a possibility to use a test with the administration of the nonsteroid antiandrogen flutamide to male patients with testicular hypogonadism to evaluate the gonadotropic reserves in this pathology and differential diagnosis of the pathogenetically different forms of this diseases in male patients aged 12 to 33. Flutamide was prescribed for internal use, 10 mg/kg a day for 5 days. Functional reserves of the hypothalamo-hypophyseal-gonadal system were estimated by the change of LH secretion with morning and daily urine after 3 and 5 days as well as by the LH, FSH and T content in the blood plasma. A significant rise of LH excretion with morning and daily urine was noted in patients with primary hypogonadism receiving flutamide. On the contrary, no significant changes in LH secretion under the influence of flutamide were detected in secondary hypogonadism. It is suggestive of the preservation of the gonadotropic reserves in primary hypogonadism and their absence in secondary hypogonadism. The test is proposed for differential diagnosis in diagnostic difficulties. The most accurate results are obtained by using LH in the urine collected for 3 days of flutamide intake.

Adolescent↗