Effects of sub-chronic aluminum chloride on spermatogenesis and testicular enzymatic activity in male rats

Aims

The aim of this study was to determine the effects of sub-chronic aluminum chloride (AlCl₃) on spermatogenesis and testicular enzymatic activity in male rats.

Main methods

Forty Wistar male rats were randomly divided into four groups: control group (CG, 0), low-dose group (LG, 64.18 mg/kg BW AlCl₃), mid-dose group (MG, 128.36 mg/kg BW AlCl₃) and high-dose group (HG, 256.72 mg/kg BW AlCl₃). The rats were orally administered with AlCl₃ for 120 days. At the end of the experiment, the contents of Al, Fe, Cu and Zn, the enzyme activities of testicular acid phosphatase (ACP), succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), lactate dehydrogenase isoenzyme (LDH-x), the sperm count and the sperm malformation rate were examined.

Key findings

The results showed that the Al and Cu contents, sperm count and the enzyme activities of testicular ACP, SDH, LDH and LDH-x decreased, while the Zn and Fe contents and sperm malformation rate increased in AlCl₃-treated rats.

Significance

It suggests that sub-chronic AlCl₃ disorders the balance of trace element and decreases the spermatogenesis and the activities of testicular enzymes, indicating that AlCl₃ has adverse effect on the testicular function in male rats.     

Mangiferin ameliorates aluminium chloride-induced cognitive dysfunction via alleviation of hippocampal oxido-nitrosative stress,proinflammatory cytokines and acetylcholinesterase level

Mangiferin is a phytochemical primarily present in the stem, leaves and bark of Mangifera indica. It offers neuroprotection mainly through inhibition of oxidative stress, and decreasing proinflammatory cytokines level in the brain. Aluminium has been reported to cause oxidative stress-associated damage in the brain. In the present investigation, protective effect of mangiferin against aluminium chloride (AlCl₃)-induced neurotoxicity and cognitive impairment was studied in male Swiss albino mice. AlCl₃ (100 mg/kg) was administered once daily through oral gavage for 42 days. Mangiferin (20 and 40 mg/kg, p.o.) was given to mice for last 21 days of the study. We found cognitive dysfunction in AlCl₃-treated group, which was assessed by Morris water maze test, and novel object recognition test. AlCl₃-treated group showed elevated level of oxidative stress markers, proinflammatory cytokines level and lowered hippocampal brain-derived neurotrophic factor (BDNF) content. Mangiferin (40 mg/kg) prevented the cognitive deficits, hippocampal BDNF depletion, and biochemical anomalies induced by AlCl₃-treatment. In conclusion, our data demonstrated that mangiferin offers neuroprotection in AlCl₃-induced neurotoxicity and it may be a potential therapeutic approach in the treatment of oxido-nitrosative stress and inflammation-associated neurotoxicity.     

Magnesium uptake by Al-stressed maize plants with special emphasis on cation interactions at root exchange sites

As aluminium (Al) severely inhibits magnesium (Mg) uptake by many plant species, Mg uptake and Mg-Al interactions in maize (Zea mays L.) were studied in a series of short and long-term experiments. A relationship between Mg uptake and the degree of Mg saturation of exchange or binding sites of the root apoplast (root-CEC) was studied by growing plants in solutions containing: (i) different concentrations of Al, calcium (Ca) and hydrogen (H) ions; and (ii) a number of organic complexes of Al. In short-term experiments, Ca had little effect on the Mg nutrition of maize plants. However, with increasing concentrations of Al and H ions in nutrient solution, there was a decrease in both the degree of Mg saturation of root-CEC and Mg uptake. Effects of pH on cation (H, Al, Mg, Ca) binding at the root apoplasm were pronounced and complicated because of a simultaneous change of H ion concentration, effective root-CEC and Al speciation. The behaviour of Al as organic Al complexes differed from that supplied as aluminium chloride (AlCl₃). In the presence of organo-Al complexes, less Mg was replaced from apoplastic binding sites and Mg uptake was inhibited less severely than with AlCl₃. In a long-term experiment, Al-citrate, in contrast with AlCl₃, was not phytotoxic to maize, expressed by the lack of any inhibition of shoot biomass production.     

The released polysaccharide of the cyanobacterium Aphanothece halophytica inhibits flocculation of the alga with ferric chloride

The effect of the released polysaccharide (RPS) of the cyanobacterium Aphanothece halophytica GR02 on the recovery of the alga by flocculation with ferric chloride was studied. With increasing RPS concentration in algal cultures from 0 to 68 mg L⁻¹ the flocculation efficiency at the same dosage of ferric chloride decreased, and higher dosages of ferric chloride were required to attain the same flocculation efficiency. It is demonstrated that RPS could form complexes with ferrum during flocculation. In conclusion, RPS of A. halophytica GR02 had a significant inhibitory effect on flocculation of the alga with ferric chloride. The inhibitory mechanism of A. halophytica GR02 RPS allows the RPS to compete for ferrum by forming complexes with ferrum, thus leading to the consumption of ferrum in ferric chloride.     

Some observations on the reductive ring opening of 4,6-O-benzylidene acetals of hexopyranosides with the borane trimethylamine-aluminium chloride reagent

Reductive ring openings of 3-O-benzoyl-4,6-O-benzylidene-d-glucopyranosides with BH₃·NMe₃–AlCl₃ are accompanied by side reactions, such as debenzoylation and reduction of the benzoate to benzyl ether. This phenomenon was rationalized by aluminium chelate formation between the O-4 acetal and the benzoyl carbonyl group oxygens. It was also shown that these side reactions can be eliminated by using BH₃·THF as the reducing agent.     

A comparison of regulatory effects of chloride on nitrate uptake, and of nitrate on chloride uptake into Pisum sativum seedlings

Net nitrate uptake, ³⁶ClO^?₃/NO^?₃ influx and ³⁶Cl^? influx into Pisum sativum L. cv. Feltham First seedlings have been examined following growth in culture medium containing different combinations of chloride and nitrate. When young (6 days old) seedlings, that had been grown in the absence of N were used, nitrate accumulation stimulated net nitrate uptake and ³⁶ClO^?₃/NO^?₃ influx (r²= 0.99) while chloride accumulation inhibited nitrate uptake and ³⁶ClO^?₃/NO^?₃ influx (r²= 0.65). When nitrate was provided during growth there was no effect of chloride pretreatment on net nitrate uptake and there was little effect of total [NO^?₃+ Cl^?]_i on ³⁶ClO^?₃/NO^?₃ influx (r²= 0.26). A direct effect of Cl^? on ³⁶ClO^?₃/NO^?₃ influx was only found when seedlings had been starved of N for more prolonged periods (14 days). When moderate chloride was supplied during growth, ³⁶Cl^? influx was insensitive to nitrate or chloride accumulated, but significantly correlated with log_e [NO^?₃+ Cl^?]_i (r²= 0.75). When trace amounts of Cl^? were supplied during growth ³⁶Cl^? influx was inhibited by (a) NO^?₃ in the external medium and (b) Cl^? pretreatment, but was insensitive to NO^?₃ pretreatment. The sensitivity of ³⁶Cl^? influx to external nitrate was not found following Cl^? pretreatment in the absence of nitrate. The possibility that there are two populations of chloride carriers which differ in their sensitivity to external nitrate is discussed. Tentative schematic models to account for the regulation of nitrate and chloride uptake are proposed in the context of current hypotheses for regulation of ion transport and control systems theory.     

Effect of aluminum chloride on mitogenesis,mitosis, and cell cycle in human short-term whole blood cultures: Lower concentrations enhance mitosis

Aluminum, the third most common element in the earth's crust (second to oxygen and silicon) and recently suspected by some investigators to be implicated in Alzheimer disease etiology, has been studied in relation to its effect on mitogenesis, mitosis, and cell cycle. We have observed that 2–4 mM concentrations of AlCl₃ have decreased the number of cells that undergo mitogenesis (PHA-induced blast transformation) and mitosis in human short term whole blood cultures. We have also shown that the rate of the cell cycle was slowed down, i.e., cell cycle time was increased in the presence of AlCl₃. Also, we have demonstrated a reversible effect on aluminum-induced reduced mitotic index in long-term EBV-transformed lymphoblastoid cultures. Although safeguards such as limiting aluminum serum concentrations have been recommended to protect individuals undergoing dialysis, it should be realized that concentration accumulations of aluminum may increase over chronic exposures. Accordingly, if the number of cells stimulated by PHA is reduced in the presence of AlCl₃, there may be a reduction of immune competence, since the degree of PHA stimulation has been used as an indicator of immune response. Similar reductions in mitotic index could affect every tissue involved with cell division. Although it may not be the same for higher concentrations, from our results, we have also shown that decreased mitotic rates were reversible in long-term EBV-transformed lymphoblastoid cultures. Increased numbers of mitoses were observed in human short-term whole blood cultures that were exposed to 2 μM concentrations of aluminum chloride. The concentration is close to those found in normal human serum and within the “safeguard” range recommended for dialysis patients. A similar trend for aluminum sulfate was also observed, while preliminary results for three other aluminum species, lactate, citrate, and maltol, were also reported. Although previous reports have indicated a positive effect of aluminum on mitosis in vitro or in vivo, this is the first such report involving human material. It is clear that higher concentrations of aluminum chloride at 2.0–4.0 mM reversibly inhibit mitosis while more dilute concentrations of 1–2 μM, closer to those found in normal serum, enhance mitosis. The present results, as well as those in the literature, suggest that aluminum may be an essential element in cellular processes for optimal growth, development, and health maintenance. Future research will further test this hypothesis.     

Aluminium effect on nitrate assimilation in cucumber (Cucumis sativus L.) roots

In vivo effect of aluminium on nitrate uptake and reduction by cucumber seedlings was investigated. The high-performance liquid chromatography was used to analyse the rate of nitrate uptake. Low (0.5 mM) concentration of AlCl₃ in the nutrient solution stimulated nitrate uptake during the first 3 h. On the other hand, 6 h exposure of the cucumber seedlings to 1 or 5 mM of AlCl₃ resulted in inhibition of nitrate uptake and at 5 mM concentration of AlCl₃ the efflux of nitrate was observed. Furthermore, the amount of nitrate accumulated in cucumber roots after aluminium treatment was decreased. The noteworthy fact was observed, that at all concentrations of aluminium tested on increase of the nitrate reductase activity. This stimulation was concentration depended, but independent of the source of the enzyme. The activity of both the cytosolic and the plasma membrane bound nitrate reductase activity was enhanced in vivo. On the other hand, AlCl₃ applied in vitro only slighty decreased nitrate reductase activity.     

Mechanism for leukotriene C4 stimulation of chloride transport in cornea

Summary The leukotriene, LTC₄, exerts a stimulatory effect on chloride transport in the frog cornea. In the work described here, the mechanism of action of LTC₄ to stimulate chloride transport was studied.In corneas pretreated with indomethacin, the effect of LTC₄ was abolished, suggesting the involvement of cyclo-oxygenase products in the response. Incubation of corneas with LTC₄ resulted in a significant stimulation in PGE₂ synthesis, as determined by TLC-autoradiography and radioimmunoassay. In addition, LTC₄ was found to stimulate cAMP synthesis in the cornea, and this stimulation was blocked with indomethacin. PGE₂ was previously shown by us to be the dominant cyclo-oxygenase product formed in the frog cornea, and is capable of stimulating cAMP and chloride transport. We suggest that LTC₄ stimulation of chloride transport is mediated via activation of the cyclooxygenase pathway, resulting in enhanced PGE₂ synthesis. Elevated PGE₂ levels induce cAMP synthesis, and ultimately, the stimulation of chloride transport. Further, the activation of cyclo-oxygenase was found to be dependent on phospholipase A₂ activity. This was shown by the inhibition of the LTC₄ effect in the presence of quinacrine. Similarly, inhibition of the LTC₄ effect in the presence of trifluoperazine suggests that cyclo-oxygenase activation by LTC₄ may be mediated via calmodulin. We have previously demonstrated that the frog cornea has the biosynthetic capacity to produce LTC₄. Therefore LTC₄ may function as an endogenous regulator of chloride transport in this tissue.     

Effect of Aluminium and cAMP on Acid Phosphatase from the Apoplast of Barley and Maize Root Cells

Acid phosphatase activity inhibited by 1 mM sodium molybdate was detected at the surface of barley seedling roots and in the cell wall fraction isolated from barley and maize seedling roots. This enzyme hydrolyzed NPP, GP, and PP_i at low pH (4.0 and below). NPP hydrolysis was stimulated by magnesium (but not calcium or manganese) ions, while PP_i hydrolysis was independent of the presence of bivalent ions. The activity of phosphatase localized in the cell walls of the both crops increased in the presence of 100 M AlCl₃ or CuCl₂. Stimulation of NPP hydrolysis by micromolar concentrations of aluminium and copper as well as by millimolar concentrations of magnesium decreased in the presence of 25 M cAMP. This agrees with the previous data on the enzyme localized at the outer side of the properly oriented vesicles in the microsomal fraction of plasmalemma. The role of the root extracellular acid phosphatase loosely associated with various apoplast structures in plant adaptation to toxic effect of aluminium in the acidic soils as well as possible control of this process by cAMP secretion to the apoplast are discussed.     

Aluminum chloride causes 5-fluorouracil resistance in hepatocellular carcinoma HepG2 cells

Chemoresistance is one of the major obstacles in chemotherapy-based hepatocellular carcinoma (HCC) intervention. Aluminum (Al) is an environmental pollutant that plays a vital role in carcinogenesis, tumorigenesis, and metastasis. However, the effect of Al on chemoresistance remains unknown. 5-Fluorouracil (5-FU) is a widely used antitumor drug. Therefore, we investigated the effects of aluminum chloride (AlCl₃) on the chemoresistance of HepG2 cells to 5-FU and explored the underlying mechanisms of these effects. The results demonstrated that AlCl₃ pretreatment attenuated 5-FU-induced apoptosis through Erk activation and reversed 5-FU-induced cell cycle arrest by downregulating p-Chk2^Thr68 levels. In addition, AlCl₃ markedly increased the levels of proteins associated with cell migration, such as MMP-2 and MMP-9. Further investigation demonstrated that an Erk inhibitor (U0126) reversed the AlCl₃-induced decrease in apoptosis, enhancement of cell cycle progression, promotion of cell migration, and attenuation of oxidative stress. In summary, AlCl₃ induced chemoresistance to 5-FU in HepG2 cells. The present study suggests a potential influence of AlCl₃ on 5-FU therapy. These findings may help others to understand and properly address the resistance of HCC to chemotherapeutic agents.     

Effects of sub-chronic aluminum chloride exposure on rat ovaries

Aims

This experiment investigated the effects of sub-chronic aluminum chloride (AlCl₃) exposure on rat ovaries.

Main methods

Eighty female Wistar (5 weeks old) rats, weighed 110–120 g, were randomly divided into four treatment groups: control group (CG), low-dose group (LG, 64 mg/kg BW AlCl₃), mid-dose group (MG, 128 mg/kg BW AlCl₃) and high-dose group (HG, 256 mg/kg BW AlCl₃). The AlCl₃ was administered in drinking water for 120 days. The ovarian ultrastructure was observed. The activities of acid phosphatase (ACP), alkaline phosphatase (ALP), succinate dehydrogenase (SDH), Na⁺–K⁺-ATPase, Mg^2 +-ATPase and Ca^2 +-ATPase, the contents of Fe, Cu and Zn, and the protein expression of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) in the ovary were determined.

Key findings

The results showed that the structure of the ovary was disrupted, the activities of ALP, ACP, SDH, Na⁺–K⁺-ATPase, Mg^2 +-ATPase and Ca^2 +-ATPase, the contents of Zn, Fe and the protein expression of FSHR and LHR were lowered, and the content of Cu was increased in AlCl₃-treated rats than those in control.

Significance

The results indicate that sub-chronic AlCl₃ exposure caused the damage of the ovarian structure, the disturbed metabolism of Fe, Zn and Cu and the decreased activities of Na⁺–K⁺-ATPase, Mg^2 +-ATPase and Ca^2 +-ATPase in the ovary, which could result in suppressed energy supply in the ovary. A combination of suppression of energy supply and reduction of expression of FSHR and LHR could inhibit ovulation and corpus luteum development, leading to infertility in female rats.     

The influence of different flocculants on the physiological activity and fucoxanthin production of Phaeodactylum tricornutum

Phaeodactylum tricornutum is an economically important species of microalgae that is widely used in aquaculture, and it is rich in bioactive substances including eicosapentaenoic acid and fucoxanthin. The major bottleneck for industrialization of this species is harvesting. Flocculation is used to harvest microalgae, thus the selection of flocculants is of great importance. In this study, we compared the flocculation effect of four different chemicals (ferric chloride, aluminum sulphate, polyaluminum chloride, and aluminum potassium sulphate) on P. tricornutum. Microexamination showed that ferric and aluminum salts had similar flocculation effects on the algae. Growth and chlorophyll fluorescence measurements showed that P. tricornutum can be re-cultured after flocculation. Pigment analysis showed that flocculation did not result in degradation of fucoxanthin, which suggests that the four flocculants tested may be useful for industrial applications. The results also showed that ferric chloride was the best flocculant for harvesting P. tricornutum when the target product was fucoxanthin, as it had the least influence on the physiological activity of P. tricornutum and it did not lead to degradation of cell components. In contrast, aluminum is poisonous to the nervous system of animals and humans. In addition, the culture medium can be recycled after flocculation by ferric chloride.     

Aluminium-induced morphogenic and biochemical variations ofBacopa Monniera

Shoots and roots ofBacopa monniera (L.) Wettst. have been regenerated from nodal segments on MS medium containing combinations of NAA and BAP. The cultures showed 100% regeneration on MS (sucrose 2%) medium added with NAA (0.2 mg L^-1), BAP (0.5 mg L^-1) and glutamine (50 mg L^-1). Supplemented with aluminium chloride (up to 400 μM), this medium could ensure successful survival of regenerants. AH the regenerants, maintained on AlCl₃-supplemented medium for the last three years, failed to grow when transferred to AlCl₃-free media. Aluminium stress also induced synthesis of proline and proteins. The rate of photosynthesis decreased at increased aluminium concentrations.     

Studies of the slowly exchanging chloride in Photosystem II of higher plants

³⁶Cl^- was used to study the slow exchange of chloride at a binding site associated with Photosystem II (PS II). When PS II membranes were labeled with different concentrations of ³⁶Cl^-, saturation of binding at about I chloride/PS II was observed. The rate of binding showed a clear dependence on the concentration of chloride approaching a limiting value of about 3·10^-4 s^-1 at high concentrations, similar to the rate of release of chloride from labeled membranes. These rates were close to that found earlier for the release of chloride from PS II membranes isolated from spinach grown on ³⁶Cl^-, which suggests that we are observing the same site for chloride binding. The similarity between the limiting rate of binding and the rate of release of chloride suggests that the exchange of chloride with the surrounding medium is controlled by an intramolecular process. The binding of chloride showed a pH-dependence with an apparent pK_a of 7.5 and was very sensitive to the presence of the extrinsic polypeptides at the PS II donor side. The binding of chloride was competitively inhibited by a few other anions, notably Br^- and NO₃ ^-. The slowly exchanging Cl^- did not show any significant correlation with oxygen evolution rate or yield of EPR signals from the S₂ state. Our studies indicate that removal of the slowly exchanging chloride lowers the stability of PS II as indicated by the loss of oxygen evolution activity and S₂ state EPR signals.Abbreviations Chl chlorophyll - EPR electron paramagnetic resonance - Hepes 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid - Mes 4-morpholineethanesulfonic acid - MWCO molecular weight cut off - PPBQ phenyl-p-benzoquinone - PS II Photosystem II     

Properties of lipid bilayer membranes separating two aqueous phases: The effects of Fe+3 on electrical properties

Summary Ferric ion has been found to alter the electrical properties of lecithincholesterol-decane bilayer membranes. Within minutes after the addition of microgram quantities of FeCl₃ to the ambient aqueous phase, the resistance of the membrane falls by a factor of 10⁵ to 10⁶. No change in capacitance is observed. The resistance change is obtained with membranes made from synthetic lecithin (fully saturated fatty acids) as well as by those formed from egg lecithin. The conductance of the modified membrane exhibits both time and voltage dependent behavior; the time dependence of the current is similar to that of an inductance, and the voltage dependence of the current is exponential. Concomitant with the resistance change, the modified membrane becomes permselective, passing chloride almost to the complete exclusion of sodium. Anion selectivity can be converted to cation selectivity by the subsequent addition of certain chelating agents. Area-conductance measurements show the resistance change occurs in the thin film. The addition of a reducing agent causes the effect of the ferric ion to be reversed, and the conductance returns to that characteristic of unmodified membranes. When ferric ion is added to only one side of the membrane, the system rectifies with current ratios of up to 201. It is concluded that the alteration of membrane properties owes its origin to the hydrolysis of membrane-bound ferric ion. The interaction of ferric ion with aqueous dispersions of lecithin has been investigated by several techniques, and evidence is presented that the dispersions bind charged species of iron and that this charge diminishes under conditions where iron hydrolysis occurs.     

The effect of aluminum chloride on some steps of heme biosynthesis in rats after oral exposure

Certain disturbances in heme biosynthesis induced by aluminum chloride were examined. The experiment was performed on female rats that received AlCl₃ orally at the dose 100 mg Al/kg daily for 21 d. The effects of aluminum on the activity of delta-aminolevulinic acid synthetase (ALA-S), dehydratase (ALA-D), and heme oxygenase (O.H.) were observed on 3, 7, 14, and 21 d in liver and kidneys of rats. Also the activity of ALA-D in blood and the concentration of delta-aminolevulinic acid (ALA-U) in urine were observed. Orally administered aluminum caused increase in the activity of ALA-D in the liver and blood, and parallel decrease of ALA-U in urine (r=−0.85) of rats. Aluminum chloride also induced an increase of ALA-S and O.H. in the liver but not in the kidneys. The changes of the enzymes activity participating in heme biosynthesis after administration of aluminum may be correlated with anemia and iron metabolism in rats.     

Effects of aluminium on growth and nutrient uptake of small Picea abies and Pinus sylvestris plants

Summary The effects of aluminium concentrations between 0.2 and 30 mM at pH 3.8 ±0.2 on small plants of Norway spruce [(Picea abies (L.) Karst], Scots pine (Pinus sylvestris L.), and Scots pine infected with the ectomycorrhizal fungus Suillus bovinus (L. ex Fr.) O. Kuntze were investigated. The plants were grown at maximum relative growth rate (R_G % day^–1) with free access but very low external concentrations of nutrients. Steady-state conditions with respect to relative growth rate (R_G) and internal nutrient concentrations were achieved before addition of aluminium, which was added as AlCl₃ and/or Al(NO₃)₃. There were reductions in rg at aluminium concentrations of 0.3 mM in spruce, 6 mM in pine and 10 mM in ectomycorrhizal pine, i. e. at aluminium concentrations considerably higher than those normally occurring in the top layer of the mineral soil where most fine roots are found. Nutrient uptake rate per unit root growth rate was calculated for different nutrient elements. The uptake rate of calcium and magnesium was reduced at aluminium concentrations of 0.2 mM (spruce), 1 mM (pine) and 3 mM (ectomycorrhizal pine), without influencing R_g. The results question the validity of the hypothesis of aluminium toxicity to forest tree species at low external concentrations.     

The effect of sodium chloride on the extraction of DNA fragments during Feulgen acid hydrolysis

Synopsis Feulgen acid hydrolysis was performed on ascites tumour cells labelled with radioactive DNA-precursors. The development of fragments of apurinic acid and the extraction of purines were studied by monitoring the variations in the extraction rate during the hydrolysis when sodium chloride was either present or absent from the hydrolysis solution. The changes in the rate of extraction of purines and the alterations in the initial retardation of the apurinic acid extracting process followed approximately the same pattern. The extractability of apurinic acid fragments during hydrolysis in 0.3m HCl was found to be a maximum when the sodium chloride concentration was about 1m. Sudden exchange experiments, in which acid was substituted for sodium chloride after various times of hydrolysis, revealed a successive shortening of the extractable fragments during the low acid concentration hydrolysis. The results strengthen the view that, during hydrolysis, apurinic acid is lost from the cells through a reaction whose form is determined, first, by an initial retardation of the depolymerization, second, by the maximum length at which fragments developed through the depolymerization become soluble and are lost by diffusion, and last, at low acid concentrations, by a mechanism whose influence is equivalent to the presence of bonds between the fragments and an unextractable stable structure.     

Experimental study on the estrogen-like effect of mercuric chloride

Although mercuric chloride has toxicity on reproductive system, it is uncertain if such toxicity is induced by estrogen-like effect. To study whether mercuric chloride has the estrogen-like effect and its relevant mechanism, proliferation assay of MCF-7 human breast cancer cells, uterotrophic assay, peroxidase activity assay and estrogen receptor competitive binding assay were conducted to screen the estrogen-like effect of mercuric chloride. The MCF-7 cells proliferated in the stimulation of mercuric chloride and got to the peak at 10⁻⁷ mol/l concentration. And this proliferation could be completely blocked by estrogenic antagonist ICI182.780. In addition, mercuric chloride could increase the weight of uterus of ovariectomized SD rats and the peroxidase activity of uterus complying with dose-effect relationship. However, mercuric chloride could not affect the binding of estradiol (E₂) to estrogen receptor (ER). So mercuric chloride exhibits the estrogen-like effect through binding and activating ER rather than bind to ER by competing with E₂.