BIOCHEMICAL EFFECTS OF ESTROGENS IN NON-REPRODUCTIVE ORGANS.

Biochemical processes initiated by estrogenic hormones in the organs which are not directly related to reproduction were described in the survey on the basis of literature and the authors' own studies. The importance of these compounds in the regulation of fundamental biological processes has been established in the last decades. The biochemical mechanisms of realization of estrogen effects may be considered as potential links of pathogenesis for a number of diseases and as targets of their therapy.

Effect of ions of potassium and lithium on NO synthase expression in the human adrenal cortex.

The expression of endothelial and inducible NO synthase in the human adrenal glands was studied under a change in the concentration of K(+), which plays a regulatory role in aldosterone secretion. K(+) ions stimulated the expression of both isoforms of NO synthase in the human adrenal cortex. A stimulatory effect of K(+) on NO synthase is probably related to activation of the calmodulin system and potassium-induced translocation of protein kinase C. Lithium produced n inhibitory effect on both isoforms of NO synthase, which suggests that protein kinase C serves a major regulator of expression in the human adrenal glands.

Effect of o,p'-DDD and Li+ on apoptotic DNA fragmentation in conventionally normal and tumour tissues of human adrenal cortex.

The actions of 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane (o,p'-DDD), potassium and lithium ions upon apoptotic processes in conventionally normal and tumour tissues of human adrenal cortex were studied. There was no effect of K+ on the apoptosis in tumour tissue. o,p'-DDD--the specific drug for conservative therapy of adrenocortical cancer--enhanced the apoptotic DNA fragmentation in all tested tissues. The conclusion was made that apoptosis may be involved in curative effect of o,p'-DDD in adrenal cortex. Lithium ions, which are used in clinic as antidepressant, inhibited the apoptosis in conventionally normal tissue and in most tumours. On the other hand, lithium enhanced the DNA fragmentation in the postoperative tissue of patients with Cushing disease. The possible mechanisms mediating lithium effects on the adrenal cortex are discussed.

[Effect of 17beta-estradiol on content of cyclic nucleotides and protein kinases A and C activity in human adrenal cortex].

The influence of 17beta-estradiol on cAMP and cGMP levels, protein kinases A and C activityand corticosteroids secretion was investigated in postoperative human adrenal cortex tissue. cAMP accumulation in adrenocorticocytes increased uiider the influence of 17beta-estradiol. In vitro estradiol raised the activities of protein kinases A and C in membrane fraction of adrenal cortex tissue. Significant increasing of steroidogenesis was observed. These data support our conclusion that cAMP dependent siganling system is involved in activation of steroidogenesis by 17beta-estradiol.

Incorporation of labelled N-acylethanolamine (NAE) into rat brain regions in vivo and adaptive properties of saturated NAE under x-ray irradiation.

Regional distribution of exogenous N-palmitoylethanolamine in the rat brain was investigated in the study. Possible protective and adaptive effect of N-stearoylethanolamine under 2 Gy whole-body X-irradiation and changes of brain lipid composition were also studied. It was found that after per os administration to rats N-([9,10-3H]-palmitoyl)-ethanolamine was primarily accumulated in hypothalamus, pituitary and adrenal glands and the label amount in brain was 0.95% of the oral dose. Quantities of palmitic acid in total brain phospholipids and plasmalogen form of phosphatidylcholine were increased; free cholesterol and diacyl form of phosphatidylcholine were decreased in 2 weeks after irradiation. 11-OH-corticosteroid level in the blood of exposed rats was decreased in comparison with control animals. N-stearoylethanolamine pre-treatment prevented from increasing the plasmalogen form of phosphatidylcholine and decreasing its diacyl form and restored 11-OH-corticosteroid level in the blood of irradiated rats. Recovering of brain free cholesterol level was observed when N-stearoylethanolamine was post-treated. So, the accumulation of N-([9,10-3H]-palmitoyl)ethanolamine in brain indicates its penetration through blood-brain barrier and suggests the possible role of saturated N-acylethanolamines in brain functioning, particularly, in stress response regulation of the organism by hypothalamus-pituitary-adrenal system. N-stearoylethanolamine treatment of irradiated rats causes protective effect concerning the of irradiation induced changes in the brain lipid composition and in 11-OH-corticosteroid level and modifies phospholipid fatty acid composition.

[Estradiol-17beta activates corticosteroid synthesis and inhibits proliferation in cultured porcine adrenocortical cells]. / Estradiol-17beta aktiviruet obrazovanie kortikosteroidov i tormozit proliferatsiiu kul'tiviruemykh kletok nadpochechnikov svinei.

The influence of estradiol-17 beta on corticosteroids production and cell proliferation were studied in the cultured pig adrenocortical cells. Estradiol-17 beta considerably increased steroidogenesis, but inhibited cell proliferation. It is speculated, that cAMP mediated estradiol-17 beta effects in the adrenal cells.

Isoforms of protein kinase C and their distribution in human adrenal cortex and tumors.

The cytosol and microsomal fractions of human adrenal cortex contain 3 isoforms of protein kinase C: alpha, zeta, and epsilon. The latter fraction is present in trace amounts. No isoforms beta1, beta2, gamma and delta were found in these cell fractions. The distribution of alpha-isoform between the cytosol and microsomal fraction is determined by tissue origin: in normal tissue its content differs by no more than 10%, while in most tumors this isoform is translocated into the microsomal fraction. The distribution of zeta-isoform did not depend on tissue origin.

[Current problems of regulation of adrenocortical function]. / Aktual'nye voprosy reguliatsii funktsii kory nadpochechnykh zhelez.

The currently available data on the regulation of corticosteroid secretion are analyzed. ACTH is the main regulator during acute stress. It accelerates the biosynthesis of glucocorticoids at the stage of cholesterol delivery to the mitochondrial inner membrane where the latter is converted to pregnenolone by side-chain cleavage. The Steroidogenic Acute Regulatory Protein (STAR) could play a great role in the supply of mitochondria with cholesterol. Under chronic stress, adrenal hypertrophy is largely involved in higher corticosteroid formation. Neuropeptides, cytokines, and growth factors modulate adrenal function. Prolactin which plays a role as a mitogenic factor in many tissues takes an active part in the control of adrenal function and proliferation.

[Phosphorylation of adrenal cortex proteins by protein kinase C induced by prolactin]. / Fosforilirovanie belkov kory nadpochechnikov proteinkinazoi C, indutsiruemoe prolaktinom.

The in vitro effect of prolactin (PRL) on protein phosphorylation in male guinea pig adrenal cortex has been studied. It was found that 60 min after addition of PRL (10 micrograms/ml) to slices of adrenocortical tissue the rate of protein phosphorylation increased considerably. Autoradiographic studies revealed that at least part of the proteins are substrates for protein kinase C, since their phosphorylation increased in the presence of specific activators of protein kinase C (Ca2+, diacylglycerol, phosphatidyl serine) in the incubation medium. The molecular masses of these proteins were 95, 93, 90, 12 and 10 kDa. In extracts of PRL-treated adrenocortical tissue phosphorylation of these proteins was especially well-pronounced. Addition of staurosporine (10 nM) during incubation of the slices abolished the PRL effect on protein phosphorylation without any effect on the rate of unstimulated phosphorylation. Taking into account the ability of isolated nuclei to respond to PRL by activation of protein kinase C, the time course of PRL stimulation of protein phosphorylation was studied using preparations of isolated nuclei. The maximal increase of 32P incorporation into the proteins from [gamma-32P]ATP was observed after 60 min. Staurosporine only slightly attenuated the PRL effect.

[Effect of chloditan on the changes of activity of glutathione transferase, glutathione reductase and glutathione content in the adrenal glands and liver in rats]. / Izmenenie akrivnosti glutationtransferazy, glutationreduktazy i soderzhaniia glutationa v nadpochechnikakh i pecheni krys pri vozdeistvii khloditanom.

The chloditan (o.p-DDD, mitotane), which causes the destruction of the human and dog adrenal cortex, on the most essential system of xenobiotic metabolism: glutathione-S-transferase--glutathione has been studied. The effect of o,p-DDD on GSH level and activity of glutathione-S-transferase and glutathione reductase which maintain the level of reduced glutathione was analyzed in the adrenal and liver tissue of rats. This species is resistant to adrenocorticolytic action of o,p-DDD. It was shown that feeding of rats weighting 200-240 g with oil solution of o,p-DDD (75 mg daily) for 3 days causes the decrease in activity of glutathione-S-transferase and content of oxidazed glutathione in the adrenals with simultaneous increase of the content of reduced glutathione. The glutathione-S-transferase and glutathione reductase activity in the liver rises under the effect of o,p-DDD, the decrease of the GSH level being observed. The revealed changes may explain the species sensitivity of animals to o,p-DDD.

Trophic effect and modulation of ACTH-dependent stimulation of steroidogenesis by prolactin in guinea pig adrenal cortex.

The effect of PRL in intact guinea pig on the incorporation of specific labelled precursors into DNA, RNA, proteins and corticosteroids in adrenocortical tissue of intact guinea pig at different levels of activation of the gland were studied. PRL (2 IU/100 g daily) did not cause any significant changes until 3 days of treatment. PRL administered alone for 3 days caused significant elevation of 3H-thymidine incorporation into DNA in adrenocortical slices and no significant changes in labelling of RNA, protein and corticosteroids. In contrast, PRL administered together with ACTH (0.5 IU/100 g) for 3 days did not affect DNA synthesis but caused increase of 3H-cholesterol incorporation into cortisol and cortisone additionally to the ACTH action. Labelling of 17-deoxycorticosteroids in adrenocortical slices from animals of ACTH+PRL group either did not change significantly (aldosterone) or decreased (corticosterone).

[Regulation of hormone biosynthesis in guinea pig adrenal glands by potassium ions as affected by dihydropyridines. 1. Analysis of changes in steroidogenesis evoked by dihydropyridines]. / Reguliatsiia biosinteza formonov v nadpochechnykh zhelezakh morskikh svinok ionami kaliia pri deistvii digidropiridinov. Analiz izmenenii steroidogeneza, vyzyvaemykh digidropiridinami.

Influence of Ca2+ channel modulators BAY K 8644, nitrendipine and newly synthesized derivative of 1,4-dihydropyridine: 4-(3', 4'-dimethoxyphenyl)-2,6-dimethyl-3,5- diethoxy-carbonyl-1,4-dihydropyridine-(DHP-51) on aldosterone production by adrenocortical slices depends on K+ content in the incubation medium. The modulators only slightly influence the hormone output at low K+ level in the medium. Intensive synthesis of aldosterone at high level of potassium in the medium was prevented in the presence of DHP-51 and low concentration of BAY K 8644. DHP-51 inhibited [3H]-cholesterol incorporation into all main corticosteroids in the high-potassium medium.

[Regulation of hormone biosynthesis in guinea pig adrenal glands by potassium ions as affected by dihydropyridines. 2. Possible mechanisms of changes in steroidogenesis induced by 1,4-dihydropyridines in dispersed adrenocorticocytes]. / Reguliatsiia biosinteza gormonov v nadpochechnykh zhelezakh morskikh svinok ionami kaliia pri deistvii digidropiridinov. 2. Vozmozhnye mekhanizmy izmenenii steroidogeneza vyzyvaemykh 1,4-digidropiridinami v dispergirovannykh adrenokortikotsitakh.

Formation of aldosterone, corticosterone, cortisol and cortisone of labelled cholesterol in the dispersed adrenocorticocytes significantly intensifies at high potassium concentrations in the incubation medium. Labelling of aldosterone and corticosterone in the presence of DHP-51 remains unchanged in the medium containing 3 mmol/l of K+, but is inhibited at 8 mmol/l of potassium. Labelling of 17-hydroxylated corticosteroids, cortisol and cortisone grows at low K+ concentration and falls at the high concentration as a result of DHP-51 addition to the incubation medium. This relationship is disturbed only at high concentration of DHP-51. Incorporation of [3H]-leucine into proteins of adrenocorticocytes grows with K+ concentrations. DHP-51 causes insignificant changes in incorporation of [3H]-leucine into proteins at low potassium content, inhibiting incorporation in the medium at high K+ level. DHP-51 blocked Ca2+ transport into adrenocorticocytes, activated by raised level of potassium in the medium. The mechanism of DHP-51 action on regulation of steroidogenesis in adrenocorticocytes is discussed.

[Anabolic action of prolactin on phosphatidylcholine metabolism in guinea pig adrenocorticocytes]. / Anabolicheskoe deistvie prolaktina na metabolizm fosfatidilkholina v adrenokortikotsitakh morskikh svinok.

Isolated adrenocortical cells of guinea pigs whom injected with prolactin (PRL) during 3 days incorporated [3H] choline into phosphatidylcholine more intensively than those cells of animals in control. Labelling of intracellular pools of choline and phosphorylcholine remained unchanged, though a part of radioactivity represented by the water-soluble precursors decreased due to PRL influence. The rate of disappearance of labelled phosphatidylcholine in adrenocortical cells prelabelled with [3H] choline was lower in cells obtained from PRL-treated animals. The discharge of [3N] choline accumulated during prelabeling accelerated simultaneously. Rate of the phosphorylcholine radioactivity fall remained unchanged. The obtained data showed that prolonged influence of PRL caused a shift of the phosphatidylcholine metabolism to anabolism. That effect might be a part of the mechanism of proliferative PRL action in the adrenal cortex.

The participation of cAMP and protein kinase C in the regulation of aldosterone biosynthesis by potassium.

The mechanism of the effect of potassium ions (K+) on aldosterone production in guinea pig adrenal cortex was examined. At high K+ concentrations (approximately 8 mM) in the incubation media, aldosterone output and content was elevated, and there was a significant increase in the phosphorylation of intracellular proteins and of protein kinase C activity. Cyclic AMP levels showed a less significant increase. EGTA and lanthanum ions (La3+), and also chlorpromazine with regard to protein phosphorylation, appeared to remove the effect of raised K+ concentrations on steroidogenesis and protein phosphorylation. At low K+ concentrations, addition of EGTA led to a significant accumulation of cyclic AMP. Evidence that steroidogenesis is regulated by a cyclic-AMP-dependent mechanism at low K+ levels is presented, and we also report the first direct evidence of activation of aldosterone synthesis by protein kinase C at high K+ concentration.