[Estradiol stimulation of thyrotropic hormone elaboration in cultures of adenohypophysis obtained from intact and ovariectomized rats]. / Stimuliatsiia estradiolom vyrabotki tireotropnogo gormona v kul'turakh adenogipofiza, poluchennykh ot intaktnykh i ovari éktomirovannykh krys.

The secretion of thyrotropin by pituitary cells in culture from ovariectomized rats treated with estradiol dipropionate was after 3-4 days higher than in cultures from intact and ovariectomized rats. Moreover, 17 beta-estradiol directly stimulated the secretion of thyrotropin by adeno-hypophyseal cells of intact rats in a monolayer culture.

[Biological properties of synthetic somatostatin]. / Issledovanie biologicheskikh svoistv sinteticheskogo somatostatina.

Complex work on the assessment of biological properties of somatostatin synthesized according to a new original method was carried out. Its inhibitory action on the TTH, growth hormone and insulin secretion was demonstrated in vivo and in vitro. As a rule, somatostatin effect was expressed against the background of stimulated hormone secretion, although basal secretion inhibition was observed with respect to insulin, The inhibitory action of somatostatin on the hormonal secretion was direct, not mediated through any regulating factors.

[Effect of thyroliberin (thyrotropin releasing hormone) on the proliferation of adenohypophysis cells in monolayer culture]. / Vliianie tiroliberina (tireotropin rilizing-gormona) na proliferatsiiu kletok adenogipofiza v monosloinoi kulture.

Autoradiographic and immunohistochemical experiments were conducted to study the action of thyrotropin-releasing hormone (TRH) on the cell proliferation in 7--8-day monolayer culture or the rat adenohypophysis. There was an increase of the epithelioid and fibroblast-like cells of the S-period of the mitotic cycle 24 hours after the TRH treatment. There were no thyrotropin-positive cells labeled with 3H-thymidine.

[Effect of thyroliberin (thyrotropin-releasing-hormone) on secretion of thyrotropic hormone and prolacting in a monolayer cultrue of rat adenohypophysis]. / Vliianie tiroliberina (tireotropin-rilizing-gormona) na sekretsiiu tireotropnogo gormona i prolaktina v monsloinoi kul'ture adenogipofiza krysy.

Cells of the adenohypophysis in the primary 5--8 day monolayer culture responded to the administration of the thyrotropin-releasing-hormone (TRH) by a rapid dose-dependent release of thyrotropic hormone (TTH) and prolactin into the culture medium. This effect is independent of the serum content in the nutrient medium. Thyroxin, the thyroid gland hormone, blocks the stimulating action of TRH with respect to the TTH secretion, but not to prolactin. The blocking effect of thyroxin is apparently expressed not on the cell membranes, but in the cytoplasm, distal to cAMP, by way of the hormonal signal transmission.

[Effect of thyrotropin releasing hormone thyroxine on the activity of cytochrome oxidase in rat adenohypophysis]. / Vliianie tireotropin rilizing-gormona i tiroksina na aktivnost' tsitokhromoksidazy v adenogipofizakh krys.

Thyrotropin releasing-hormone (TRH) increased the activity of cytrochrome C oxidase in a concentration of 0.01 and 1.0 microgram/ml in the adenohypophysis of rats fed methylthiouracil for 6 weeks. This effect of TRH on the activity of the enzyme was blocked with T4 added to the incubation medium in a concentration of 20 microgram/ml. Actinomycin D (20 MICrogram/ml) prevented the block of the enzyme with thyroxin. In a concentration of 0.01 microgram/ml TRH, and in a concentration of 2.0 microgram/ml T4 failed to change the activity of cytochrome oxidase in the adenohypophysis of normal and partially thyroidectomized rats.

[Comparative assessment of the specific activity of several thyrotropin-releasing-hormone analogs]. / Sravnitel'naia otsenka spetsificheskoi aktivnosti nekotorykh analogov tireotropin-relizing-gormona

A study was made of the effect of replacement of the second and third amino acid residues of the thyrotropin-releasing hormone on the manifestation of the specific biological activity assessed by the radioimmune method of determination of the thyrotropic hormone in rats. Replacement of histidine by alanine caused a 100-fold and by phenylalanine - a 10-fold reduction of the activity. Glycine analogue proved to be inactive. The biological activity of TRH analogue (Glu-Phe-Pro CH3) was only 10 times less in comparison with the activity of the standard. The second double modified analogue of this hormone (Glu-Gly-Ser NH2) was incapable of influencing the release of the thyrotropic hormone by the hypophysis.