[A comparison of the hormonal and etholotropic activity of luliberin and its analogs]. / Sravnenie gormonal'noi i étoltropnoi aktivnosti liuliberina i ego analogov.

The paper is devoted to comparative analysis of the activity of peptides (LH-RH analogs) with relation to their action on ovulation as well as on the learning capabilities and their effect on immobilization stress in rats. The acceleration of learning processes and elimination of immobilization stress were shown to be caused by LH-RH and its analogs, regulating actively ovulation under experimental conditions. The comparative evaluation of their action has shown that LH-RH analogs-antagonists produce a more marked effect on the process of learning and elimination of stress consequences than its analogs-agonists.

[3-phase-usage contraceptives]. / Kontratseptivy trekhfaznogo primeneniia.

The main trends of improving methods of usage of oral steroidal contraceptives are reviewed. The data characterizing the features of the pharmacodynamics of three-phase usage steroidal agents, their side effects are presented.

[Effect of an estrogen-progestin preparation alone and in combination with amizil on the structure and electrophoretic parameters of oocytes and early rat embryos]. / Vliianie estrogen-progestinovogo preparata i ego kombinatsii s amizilom na strukturu i élektrofiziologicheskie parametry ootsitov i rannikh émbrionov krys.

An increasing contraceptive effect at a combined administration of steroid drugs with neurotropic substances--M-cholinolytic benactyzine, makes the problem on the character and mechanism of their action. In the experiments performed in rats, under effect of ethinyl estradiol and norethisteron acetate, and especially at their combination with benactyzine, the first signs of overmaturation are revealed in oocytes situating in the follicular cavity. Therefore, oocytes revealed in the rat fallopian tubes leave behind the development of the control oocytes. The drugs investigated, influencing maturation and ovulation mechanisms of oocytes, produce certain physiological and morphological changes in ovaries of the test rats. This, evidently, defines the mechanism of their elevated contraceptive action. Overmaturation of oocytes in follicles, ovulation at later developmental stages results in increasing amount of degenerative forms of embryos and in disturbance of their development.

[Luliberin analogs--a new class of contraceptive agents]. / Analogi liuliberina--novyi klass kontratseptivnykh sredstv.

PIP: Pharmacological activity of endogenous luliberin and its analogs is reviewed with special emphasis on their potential use as contraceptive agents. The contraceptive effect of inhibitors of the hypothalamo-hypophyseal-ovarian system can be associated with the following: neutralization of endogenous luliberin in the portal system of the pituitary with antibodies; blocking of luliberin receptor with synthetic antagonists; and inhibition of the cyclic release of endogenous luliberin after prolonged administration of agonists. Experiments with immunological contraception showed that immunization of normal rats during early proestrus with antisera against luliberin caused complete inhibition of the preovulatory release of gonadotropins, prolongation of the diestrus phase, and blocking of ovulation. The maximum neutralization of luliberin was observed 2-3 months after immunization. The disadvantage of this method of contraception was a significant decrease of estrogen levels typical for the postmenopausal period. Depending upon the dose, timing of administration, and phase of the ovulatory cycle, synthetic luliberin can have a contraceptive effect (inhibition of luteotropin peak, decrease of plasma estradiol level, prevention of the rise of progesterone level during the 2nd half of the menstrual cycle, inhibition of the ovulation). Biological activity of various synthetic analogs of luliberin was found to depend upon the chemical structure. In general, substituting amino acids in positions 6 and 10 produced agonists, while substituting amino acids in positions 1, 2, 3, and 6 produced antagonists. Administration of luliberin antagonists (usually in mg doses) produced an antiovulatory effect via the decrease in the plasma levels of gonadotropins with subsequent inhibition of gonad function). Synthetic luliberin agonists in large doses have a "paradoxical" effect mediated via hypophysis, although certain agonists were found to have a direct inhibitory effect on the gonads.^ieng

[Stimulation of ovulation with analogs of luliberin, androstenol and their combination with L-DOPA]. / Stimuliatsiia ovuliatsii analogami liuliberina, androstenola i ikh sochetaniem s L-DOFA.

The stimulating effects on ovulation of three original analogues of luliberin and three derivatives of androstenol as compared with clomiphene were shown. An increase of their effects under the conditions of activation of the adrenergic system by L-DOPA administration was also found.

[Effect of a cyclic luliberin analog on ovulation]. / Issledovanie vliianiia na ovuliatsiiu tsiklicheskogo analoga liuliberina.

A study was made of the cyclic LH-RH analog and its linear precursor on infantile and mature female rats. The compounds showed various biological properties which manifested themselves in their effects on ovulation. The linear analog proved to be an antagonist and the cyclic analog the LH-RH agonist. A hypothesis to the effect that the LH-RH biologically active conformation has a quasicyclic structure, has been confirmed.