Effect of progesterone and its synthetic analogues on the activity of mitochondrial permeability transition pore in isolated rat liver mitochondria.

The influence of progesterone and its synthetic analogues on the induction of the Ca(2+)-dependent mitochondrial permeability transition pore (MPTP) has been studied. The novel synthetic analogue of progesterone 17a-acetoxy-3b-butanoyloxy-6-methyl-pregna-4,6-diene-20-on (buterol) was compared with progesterone and medroxyprogesterone acetate (MPA). It was found that progesterone and buterol have opposite effects on the induction of MPTP opening by calcium ions. By contrast to progesterone, which decreased the calcium ion concentration necessary for pore opening, and MPA, which also, although at a lesser extent, activated the pore induction, buterol at a concentration of 20-100 microM blocked the pore opening and increased the calcium retention capacity of mitochondria more than twofold. The action of buterol is specific to the pore since it did not affect the respiration, whereas progesterone completely inhibited NAD-dependent respiration. MPA acted similar to progesterone but less effectively. The inhibitory effect of buterol was eliminated in the presence of carboxyatractyloside, which selectively binds the thiol groups of adenylate translocase and prevents the adenine nucleotide binding. These data indicate that buterol interacts with thiol groups, which explains its inhibitory effect not only on the mitochondrial pore but also on the transport system of xenobiotics in tumor cells in which buterol reduces the multidrug resistance.

Activity lysosomal enzymes in rat skin fibroblasts after treatment with progesterone and new gestagen ABMP.

The effects of a new synthetic gestagen 17alpha-acetoxy-3beta-butanoyloxy-6-methyl-pregna-4,6-dien-20-on (ABMP) and reference drug progesterone on rat skin fibroblasts were evaluated by variations in lysosomal enzyme activity (cathepsin D and beta-glucosidase). Our results suggest that ABMP exhibits lysosomotropic properties, which depended on its concentration and time of treatment. The direct effect of progesterone on lysosomal enzyme activity in skin fibroblasts was compared to the influence of systemic treatment with gestagens on skin lysosomes. The data indicate that local application of gestagen preparations holds much promise for the therapy of skin diseases accompanied by increased proliferation (e.g. psoriasis).

[Interaction of the new gestagen compound 17alpha-acetoxy-3beta-butanoyloxy-6-methylpregna-4,6-dien-20-one with human blood proteins and calf embryo serum].

Molecular mechanisms of sex hormones (progesterone, medroxyprogesterone acetate (MPA), and new synthetic gestagen 17alpha-acetoxy-3beta-butanoyloxy-6-methylpregna-4,6-dien-20-on (ABMP) with human serum albumin, globulins, and calf embryo serum were studied. The binding of ABMP to albumin and progesterone-binding proteins were investigated using spectroscopic techniques (with the use of 1-anilino-8-naphthalenesulfonate as fluorescent probe) and radiolabeled progesterone, (either progesteron or MPA as comparative progestines). There is no difference between the non-specific binding of ABMP, progesterone, and MPA, but the ABMP binding is much smaller as compared to the binding of progestines, so that the new progestine ABMP will produce a more effective action on the target tissue than comparative progestines.

[A new Russian gestagen with anticancer activity].

The authors present results obtained in a complex study of 17alpha-acetoxy-3beta-butanoyloxy-6-methyl-pregna-4,6-dien-20-on (ABMP). ABMP was shown to differ from existing analogues by high gestagen activity and prolonged action. The substance does not possess androgenic or mineralocorticoid activity, is not toxic when used in high doses, and possesses significant cytostatic and chemiosensitizing activity. These properties of ABMP demonstrate that the substance should be studied in clinical setting as a gestagen with anticancer and chemiosensitizing activity for further application to therapy of hyperplastic processes in the female genital system and tumors that are sensitive to female sex hormones.

[Influence of the structure of synthetic gestagens on their binding to progesteron receptors in the endometrium].

Chemical modification of progesterone molecule leads to changes both in the gestagenic activity of new derivatives and in their specific binding with progesterone receptors. The passage from esters (acetomepregenole, butagest) to the corresponding OH-forms such as 17a-acetoxy-3b-hydroxy-6-methyl-pregna-4,6-dien-20-one (ABMP)is accompanied by an increase in the binding with progesterone receptors in vitro. The translocation of a double bond from endocyclic (N6-N7) to exocyclic position (methylene group at N6 in ABMP) has no significant effect on the ability to binding with progesterone receptors.

[Genomic and extragenomic mechanisms of antiglucocorticoid action of gestagens on thymocytes].

Effects of a new synthetic progesterone derivative 17a-acetoxy-3b-butanoyloxy-6-methyl-pregna-4,6-dien-20-one (ABMP) and the reference gestagen preparations on the rat thymus were evaluated by the degree of variation of the intracellular levels of calcium and cAMP, 3H-uridine inclusion into RNA, thymocyte viability, and thymus mass. It is shown that gestagens can produce antiglucocorticoid action on thymocytes, this activity being most pronounced in the case of ABMP.

[Antitumor activity of the new gestagen 17alpha-acetoxy-3beta-butanoyloxy-6-methyl-pregna-4,6-dien-20-one]. / Izuchenie protivoopukholevoi aktivnosti novogo gestagena 17 al'fa-atsetoksi-3 beta-butanoiloksi-6-metil-pregna-4,6-dien-20-ona.

Antitumor activity of a new highly active promising gestagen 17alpha-acetoxy-3beta-butanoyloxy-6-methyl-pregna-4,6-dien-20-one (butagest) was studied in mice with model cervical carcinoma (RShM-5). The reference drug was medroxyprogesteron acetate (MPA, Depo Provera) used in clinics. The new preparation introduced perorally in a dose of 1 mg per mice inhibited the model tumor growth by 73%, which was 18% (p < 0.01) more effective than the action of the reference drug MPA. The effect of the new gestagen was also studied in vitro with respect to human breast carcinoma of the MCF-7 line and human cervical carcinoma HeLa. The viability of the tumor cells was studied during a 6-day incubation with the drug at a concentration of 10(-7)-10(-5) M (MTT test). The reference compounds were progesterone and MPA. These drugs suppressed the growth of both MCF-7 and, in higher concentrations, of HeLa. Butagest inhibited the growth of HeLa in all concentrations. Thus, the new gestagen 17alpha-acetoxy-3beta-butanoyloxy-6-methyl-pregna-4,6-dien-20-one is capable of suppressing the viability of human breast carcinoma and human cervical carcinoma, being comparable or even more effective than the reference drugs.

[Experimental progestogenic activity of novel derivatives of 17alpha-hydroxyprogesterone]. / O gestagennoi aktinosti novykh proizvodnykh 17alpha-gidroksiprogesterona v éksperimente.

Experiments on infantile female rabbits showed that new 17a-hydroxyprogesterone derivatives (AMOL phenyl propionate, AMOL isopropyl ester) possess a pronounced gestagenic activity. In particular, AMOL isopropyl ester is capable of maintaining pregnancy in ovariectomized animals (Corner-Allen assay).

The effect of acute stress and opioid antagonist on the activity of NADPH-P450 reductase in rat Leydig cells.

Previous studies indicate that acute immobilization stress (IMO; 2 h) impaired testicular steroidogenesis primarily at the testicular level decreasing the activity of certain steroidogenic enzymes. In the present study unstressed rats as well as IMO rats (2 h) were treated by intratesticular injection of naltrexone methobromide (NMB; peripheral opioid receptor antagonist; 36 microg/testis) or vehicle at the beginning of and at 1 h of the IMO period. In IMO rats the activity of P450c17 was significantly reduced as well as the activity of NADPH-P450 reductase (which catalyzes the transfer of electrons from NADPH to cytochrome P450), while the activity of NADH-b5 reductase was not affected. Present data confirmed previous results that acute IMO reduced testicular P450c17 activity and implicate that decreased activity of NADPH-P450 reductase could be responsible for the inhibition of P450c17 under IMO conditions, while NADH-b5 reductase is probably not involved. NMB treatment antagonized the inhibitory effect of IMO on P450c17 and NADPH-P450 reductase activities. Such results put forward the implication that endogenous opioid peptides are involved in mediating the inhibitory effect of IMO on testicular steroidogenesis, and allow the speculation that NADPH-P450 reductase could be a possible site of such an inhibition.