[The electrographic picture of sleep as affected by a thyroliberin analog]. / Elektrograficheskaia kartina sna pri deistvii analoga tiroliberina.

The neurotropic effects of pyroglutamyl-seryl-phenylalanine amide, the thyrotropin-releasing hormone analog, have been studied in experiments on male rats. Electrodes were implanted in the hippocamp and the optic cortex for registration of electroencephalograms. The analog administered intraperitoneally decreased the time of onset of slow sleep increasing the duration of this phase. The effects of the analog increased with an increase in a dose of the agent.

[Effect of a calcium channel blocker on the hypophyseal secretion of luteinizing hormone in intact and castrated rats of both sexes]. / Vliianie blokatora kal'tsievykh kanalov na sekretsiiu liuteiniziruiushchego gormona gipofizom u intaktnykh i kastrirovannykh krys oboego pola.

The effect of verapamil on luteinizing hormone secretion by pituitary body was studied in normal and castrated male and female rats. Intragastric verapamil administration at a dose of 10 mg/g body weight two hours prior to decapitation decreased luteinizing hormone serum and pituitary levels in female rats only in proestrus. It is suggested that preovulatory luteinizing hormone secretion depends partially on estradiol-stimulated calcium transport.

[Relation between the modulating effect of estradiol on the secretion of the pituitary luteinizing hormone and calcium ions in ovariectomized animals]. / Zavisimost' moduliruiushchego deistviia éstradiola na sekretsiiu liuteiniziruiushchego gormona gipofizom ot ionov kal'tsiia u ovariéktomirovannykh zhivotnykh.

The effect of verapamil, the blocker of calcium channels, on estradiol modulation of the LH-RH effect on the secretion of the luteinizing hormone was studied in experiments on ovariectomized rats. It was shown that verapamil influenced neither the basal nor the LH-RH activated secretion of the hormone from the pituitary gland. However verapamil inhibited the effect of estradiol increasing the secretory response to LH-RH. Hence, the modulating effect of estradiol on the secretion of the luteinizing hormone depended on the transport of extracellular calcium into hypophyseal cells.

[Participation of brain neuromediator systems in the action of parlodel on prolactin and luteinizing hormone secretion by the rat hypophysis]. / Uchastie neiromediatornykh sistem mozga v deistvii parlodela na sekretsiiu prolaktina i liuteiniziruiushchego gormona gipofizom krys.

The data are presented, obtained in experiments on cyclic female rats. The blood prolactin and luteinizing hormone content was examined and the dopamin level in the preoptic region and mediobasal hypothalamus was determined after a single parlodel injection to animals during the proestrous and/or estrous stage. The most pronounced effect of the drug manifested itself in a decrease in the blood prolactin content, especially in rats within the proestrous stage and, to a lesser degree, during the estrous cycle. An increased dopamin level in the mediobasal hypothalamus and the brain preoptic region of the animals during the proestrous stage was probably secondary. Marked changes in the serotonin levels were not revealed. It is suggested that the relationship between the lactotropic and luteotropic functions of the hypophysis is conditioned, to a considerable extent, by the dopaminergic system of both brain regions, involving in regulation of the gonadotropin secretion. The cyclicity disturbance was not prevented and the estrous cycle was not restored in female rats under experimental conditions of hyperestrogenemia after dopamin precursor injection.

[Role of dopamine in the regulation of the thyrotropic function of the pituitary gland]. / Rol' dofamina v reguliatsii tireotropnoi funktsii gipofiza.

Acute experiments on sexually mature mongrel male rats showed that microinjection of dopamine into the area of paraventricular nucleus of the hypothalamus and the anterior lobe of the hypophysis failed to influence the secretion from the hypophysis of the thyrotropic hormone (TTH), the content of which was determined radioimmunologically. Dophamine injections in the mediobasal hypothalamus decreased the TTH content in the blood of euthyroid rats. In animals given thyroxin preliminarily, an increase in the TTH level occurred in the blood serum in response to dophamine administration into the mediobasal hypothalamus. A conclusion was drawn that dophamine of the mediobasal hypothalamus took part in the TTH secretion from the anterior lobe of the hypophysis. The normalizing action of the given mediator is expressed under conditions of the changed functional activity of the hypophysis-thyroid gland system.

[The role of noradrenaline in regulating the thyrotropic function of the hypophysis]. / Rol' noradrenalina v reguliatsii tireotropnoi funktsii gipofiza

Acute experiments were conducted on male rats; a study was made of the effect of microinjections of noradrenaline into the hypothalamus on the thyrotropic function of the hypophysis. Administration of the mediator into the anterior part of the medio-basal hypothalamus led to reduction of the level of thyrotropic hormone in the blood serum and its accumulation in the hypophysis in determination by radioimmunological method. Noradrenaline injections into the area of the paraventricular nucleus practically did not alter the thyrotropic function of the hypophysis.

[The relationship between changes in the concentration of catecholamines in the hypothalamus and the level of thyroid hormones in the body]. / Izmeneniia kontsentratsii katekholaminov v gipotalamuse v zavisimosti ot urovnia tireoidnykh gormonov v organizme

Fluorimetric method was applied to determination of the dopamine, noradrenaline and adrenaline content in the tissues of the brain of male rats. Catecholamine distribution in the hypothalamus was uneven. Hyprthyroid state decreased the concentration of dopamine in the anterior and the middle hypothalamus, and also in the preoptic area; removal of the throid gland produced no significant changes in the dopamine, noradrenaline or adrenaline concentration.