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Properties of the adenylate cyclase in the oocytes of starfish Asterias amurensis
Camp. Bkx-hem. Physiot. Vol. 103C, No. 2, pp. 379-382, Printed in Great Britain
1992
Q
~305~$492192 $5.00 + O.WJ 1992 Pergamon Press Ltd
PROPERTIES OF THE ADENYLATE CYCLASE IN THE OOCYTES OF STARFISH ASTERIAS A~URE~~rS N. E. LAMASH* and Yu. S. KHOTIMCHENKO Laboratory of Regulation of Reproduction, Institute of Marine Biology, Far East Science Center, Academy of Sciences of Russia, Vladivostok 690022, Russia
Abstract-l.
Properties of the membrane-bound form adenylate cyclase in Asrerias umurrnfir oocytes have been investigated. 2. Mn’+ activated enzyme activity of starfish oocytes. 3. Starfish cyclase is activated by guanine nucleotides, fluoride, forskohn and cholera toxin, thus demonstrating the presence of regulatory subunity (G-protein). 4. It was suggested that the starfish membrane oocytes have receptor-like structures which are sensitive to dopamine and ones related with adenylate cyclase.
MATERIALS AND
I~RODU~I~N Recently, it was established cantain biogenic monoamines
that
starfish
Asterias amurensis.
*Author to whom correspondence
GTP, cholera toxin, dopamine, adrenahn, noradrenalin were from Sigma Chemical Company. Other chemicals used were of analytical grade. Adult Arteries utnurensis wm collected in March (1990) from Peter the Great Bay, Japan Sea. Female gonads were dissected by cutting the starfish body and gently tearing open in ice-cold calcium-free artificial seawater (CaFASW). The suspension was filtered throuah a double layer of cheese-cloth and washed three or four tl’mes in CaFASW using a hand centrifuge to remove the I-MeAproducing fotficlecells. Dense oo&te suspension was used to obtain “plasma membrane-rich fraction” as described by Dome er al. (1978). The adenylate cyclase activity was measured as in Tkachuk and Baldenkov (1978). Assays were routinely performed in 50~1, containing 2mM ATPI SmM MgCl,. 20 mM Tris--HCi, pH 7.5. 10 mM theophylline, plus an ATP system (5 mM phosphocreatinine, 3.2 regenerating unit/assay creative phosphokinase). The reaction was initiated by adding 50~1 of protein and continued for 20min at 20°C. It was stopped by boiling and subsequent cooling. Assays were centrifuged for 10 min at 3000 rpm and the supernatant was used to determine the amount of the resultant c-AMP. as described by Jihnan (1970). The content of protein optima1 for determjnation of adenylate cyclase activity was IO-i~~g~assay. in our experiments the concentration of protein was 20.-30 pg/assay. All assays were done in triplicate and the interassay standard error was ~5%.
tissues
which are known to be mediators of the m5noaminergic system (Cottrell and Pentreath, 1970; Huet and Franquinet, 1981). The seasonal dynamics of the level of these hormones was investigated during the reproductive season and from the results obtained it was inferred that the monoaminergic system can participate in the regulation of gametogenesis (Khotim~henko and Deridovich 1988). Many of the physiological actions of biogenic monoamines are ~ondiiioned by the activation of adenylate cyclase which leads to intracellular accumulation of cyclic 3,5-AMP. The intracellular c-AMP regufates synthesis of many organic components of the cell and enzyme activity. The role of c-AMP in echinoderm gametes is still not clear. It has been suggested that cyclic nucleotides can regulate sperm motility, enzyme productivity in eggs and energetic metabolism of sperms and eggs (Garbers et al., 1980; Kopf. 1977; Lee, 1976; Nath, 1973). Also, the induction of meiosis involves a depression in CAMP tevel in starfish 55cytes {Neijer and Zarutskie, 1987). The hormone-sensitive adenylate cyclase has been described in fairly great detail in membranes of the somatic ceils. considerably less is known about components of the system of cyclic nucleotides of the sex cells (Mourelle et al., 1984; Finidory, 1982; Chiba, 1989; Capasso, 1987, 1989) Such investigations can, in our opinion, be useful for understanding ovo- and spermatogenesis. The present work is the first attempt to study the functional characteristics of hormone-sensitive adenylate cyclase system of oocytes of the starfish
should be addressed.
Abb~e~iutioff used: G, guanine nucl~ot~de-binding protein,
METHODS
RESULTS
The kinetic parameters (K, and V,,,) were determined using MgATP as substrates. Cyclase activity followed Michaelis kinetics with K,, = 0.25 mM, V,,, = 2-3 pmoles cAMP/mg protein/min. The presence of Mn’+ had a stimulatory effect on the adenylate cyclase in the starfish oocyte membranes (Fig. 1). Adenylate cyclase was activated by NaF, GTP, cholera toxin and forskohn (Table I). NaF showed a maximal stimulatory effect at a concentration of lOmM (assay). GTP enhanced the enzyme activity only at high concentrations of 10-5-10-4M. The
379
N. E.
380
LAMASHand
Yu S. KHOTIMCHENKO
Catecholamine concentration Fig. 1.
Effect of increasing concentrations of MnCl, on the adenylate cyclase of starfish oocyte.
starfish oocyte cyclase responds to stimulation by pretreatment with cholera toxin. Specific activator of adenylate cyclase-foreskolin produced an effect at 10-5-10-4 M and lower concentrations of this substance proved ineffective. Catecholamines (adrenalin, noradrenalin and dopamine) stimulated adenylated cyclase activity. Maximal activation by adrenalin and noradrenalin was obtained at lo-’ M. Stimulatory effect of dopamine in low concentrations was the greatest (Fig. 2). Serotonin in concentrations of 10-5-10-4M had no effect on adenylate cyclase activity.
The presence of noradrenalin and dopamine in the starfish gonads and the change in the sensitivity of oocytes to these substances during gametogenesis allow us to assume that catecholamines may influence the successful course of events in ovogenesis. As it was noted, catecholamines produce their regulatory effect on the functional activity of the target cells via the adenylate cyclase system. Proceeding from this, we have made an attempt to determine whether in plasma membranes of starfish oocytes, there is a hormone-sensitive adenylate cyclase similar to those described for other cells. According to the model proposed by Lefkowitz (1983) this system consists of three interacting subunits-receptory, regulatory and catalytic. By its properties such as the use of a MgATP as a substratum and the ability to be activated by Mn 2+, the catalytic subunit of the adenylate cyclase system of starfish oocyte membranes is not different from that in Xenopus laevis oocytes (Finidory et al., 1982) sea urchin Lytechinus pectus sperm (Mourell et al., 1984) and invertebrate somatic cells. In our view, an S-like character of the curve describing the dependence of the basal enzyme activity on the concentration of Mn2+ can be explained by the fact that the enzyme binds free Mn2+ addition Table I. Addition None
NaF Forskolin GTF Cholera toxin
IO 2 10-S 10-h 10-5 lWflg/ml
(pm&s
of
Activity cAMP/mg prot/min)
0.89 + 42.51 + 7.38 f 15.82* 5.42 + 4.82 z
0.09 3.21 0.82 I.10 0.20 0.06
(
M
)
Fig. 2. Adenylate cyclase stimulation by various catecholamines. m-control, m-adrenalin, q-noradrenalin, qAopamine. Membranes were assayed in the presence of the indicated
factors.
to MnATP. Which of the adenylate cyclase complex has sites for the cations has not yet been determined. Hanski (1981) and Sternweis (1981) believe that merely one of the subunits of G-protein in the erythrocyte plasmolemma possesses such an ability, whereas Ferguson (1982) does not rule out the possibility that these sites can be located on the catalytic subunit also. In studying the regulatory subunit, we used as functional markers NaF, guanine nucleotides and cholera toxin. In our experiments, guanyl nucleotides stimulated the adenylate cyclase only at high concentrations. This may be due to a strong GTP-ase activity of the regulatory subunit (G-proteins). Thus, after incubation of membranes of Xenopus laevis oocytes with cholera toxin, the stimulatory effect is achieved by the use of GTP (Finidori, 1982). Since activation can be effected by guanine nucleotides, NaF and cholera toxin, thus demonstrating the presence of a functioning guanine nucleotide binding protein (regulatory subunit). It does not differ from regulatory components of the adenylate cyclase system in both somatic and sex cells. The most complicated problem is the characterization of the receptory subunit of adenylate cyclase, because major differences found among membraneassociated adenylate cyclases concern primarily this subunit (Pertseva et al., 1987). Recent studies suggest the presence of neurotransmitter receptors in the oocyte membrane of echinoderms, amphibians, birds and rats which disappear after maturation and/or fertilization. At the same time, adenylate cyclase activity in the plasmolemma also disappears (Kusano et al., 1978, 1982; Eusebi et al., 1984; Rostomyan et al., 1985; Buznikov, 1983). However, these receptors have not yet been identified probably because of their small number. Catecholamines can produce their action via adrenoreceptors of the p-type (Levitzki, 1978). In this case, according to the degree of their effect on adenylate cyclase, they can be arranged into isoproterenol > adrenalin > the following range: noradrenalin. As shown in the present work, the adenylate cyclase of starfish oocytes is equally sensitive to adrenalin and noradrenaline, while dopamine in low concentrations (IO-*-lo-’ M) caused the maximal activation of the enzyme. This finding can be evidence for the absence of typical P-adrenergic receptors associated with adenylate cyclase. It is
Adenyl cyclase in starfish oocytes known that the effect of catecholamines may be mediated by other receptors, as it was shown for the nerve tissue of insects (Sieghart et al., 1976) and muscles of molluscs (Pertseva et al., 1987). In the latter case, serotonin receptors were assumed to be mediators. However, in our experiments, serotonin did not influence cyclase activity. It is possible that in the starfish oocyte membranes there can be dopamine receptor-like structures such as those described for sea urchin oocyte membranes (Capasso, 1987). This is confirmed by the results from in vitro experiments with gonad fragments of the starfish Asterius amurensis. After the addition of dopamine to the incubation medium, the c-AMP level in the ovaries increased as well as increased the amount of the precipitate of the cytochemical reaction that identifies the adenylate cyclase on the outside of the membrane. Haloperidol, an inhibitor of the dopamine receptors, eliminated the effect of dopamine (Deridovich et al., 1988). Also, we have reported that in the ectoneural and endoneural regions of the central nervous system of A. amurensis, dopamine and noradrenalin were found in concentrations of 4.32 pg/g wet weight and 2.86 pg/g wet weight, while serotonin and adrenaline were either absent or present in very small amounts (Khotimchenko et al., 1988, 1989). Only special studies are required to answer the question as to which receptor type is involved in adenylate cyclase activity in the starfish oocyte membranes. SUMMARY
The adenylate cyclase system in the membrane oocyte of Asterias amurensis has been studied. Starfish cyclase is activated by guanine nucleotides, fluoride, forskolin, cholera toxin and Mn’+. Only dopamine out of the tested biogenic amines (adrenalin, noradrenalin, serotonin) stimulates the adenylate cyclase activity by low (lo-* M) concentrations, which agrees with the fact that this neurohormone is a main neuromediator in starfish. It was suggested that the membrane oocytes have receptor-like structures which are sensitive to dopamine. We believe that in the starfish oocyte membrane there is a hormone-sensitive adenylate cyclase similar to those described for other cells. Acknowledgements-We
thank Dr L. A. Kusnetsova for her skilful and methodical assistance. REFERENCES
Buznikov G. A., Malchenko L. A. and Rakic L. (1984) Sensitivity of starfish oocytes and whole, half and enucleated embryos to cytotoxic neuropharmacological drugs. Comp. Biochem. Physiol. 78C, 197-201.
Capasso A., Parisi E., De Prisco P., De Petrocellis B. (1987) Catecholamine secretion and adenylate cyclase activation in sea urchin eggs. Cell Biol. Int. Rep. 11, 457463. Capasso A., Creti P., De Prisco P. P. and Parisi E. (1988) Role of dopamine and indolamine derivatives in the regulation of the sea urchin adenylate cyclase. Biochem. biophys. Res. Commun. 154, 758-764. Chiba K. and Hoshi M. (1989) Pertussis toxin bloks Imethyladenine-induced
381
382
N. E. LAMASH and Yu S. KHOTIMCHENKO
P. (1987) Star&h oocyte Meijer L. and Zarutskie maturation: I-methyladenine triggers a drop of CAMP concentration released to the hormone-dependent period. Devl Biol. 121, 306-315. Nath J. and Rebhun L. I. (1973) Studies on cyclic AMP levels and phosphodiesterase activity in developing sea urchin eggs. Expl Cell Res. 77, 319-322. Pertseva M. N. and Soltitskaya L. P. (1987) Properties of the adenylate cyclase system in the muscular-tissue of mollusk. Anodonta cy,gnea. J. Biochem. (Ukraine) 59. _14-20. Rostomyan M. A., Abramyan Y. S., Buznikov G. A., Gusareva E. V. (1985) Electron cytochemical detection of
adenylate cyclase in embryos of sea urchin. Cytology 27, 877-881. Sieghart W., Leitich H., Karobath M. (1976) Subcellular distribution of dopamine-sensitive adenylate cyclase. Brain Res. 109, 418422. Sternweis P. C., Northrup J. K., Smigel M. D., Jilman A. G. (1981) The regulatory component of adenylate cyclase: purification and _ properties. J. biol. Chem. 256, _ <1,517-l-1,526. Tkachuk V. A.. Baldenkov G. N. (1978) Isolation. nurification and characterization of regulatory properies of adenylate cyclase from rabbit heart. Biochemistry 43, 1097-l 110.
1992
Q
~305~$492192 $5.00 + O.WJ 1992 Pergamon Press Ltd
PROPERTIES OF THE ADENYLATE CYCLASE IN THE OOCYTES OF STARFISH ASTERIAS A~URE~~rS N. E. LAMASH* and Yu. S. KHOTIMCHENKO Laboratory of Regulation of Reproduction, Institute of Marine Biology, Far East Science Center, Academy of Sciences of Russia, Vladivostok 690022, Russia
Abstract-l.
Properties of the membrane-bound form adenylate cyclase in Asrerias umurrnfir oocytes have been investigated. 2. Mn’+ activated enzyme activity of starfish oocytes. 3. Starfish cyclase is activated by guanine nucleotides, fluoride, forskohn and cholera toxin, thus demonstrating the presence of regulatory subunity (G-protein). 4. It was suggested that the starfish membrane oocytes have receptor-like structures which are sensitive to dopamine and ones related with adenylate cyclase.
MATERIALS AND
I~RODU~I~N Recently, it was established cantain biogenic monoamines
that
starfish
Asterias amurensis.
*Author to whom correspondence
GTP, cholera toxin, dopamine, adrenahn, noradrenalin were from Sigma Chemical Company. Other chemicals used were of analytical grade. Adult Arteries utnurensis wm collected in March (1990) from Peter the Great Bay, Japan Sea. Female gonads were dissected by cutting the starfish body and gently tearing open in ice-cold calcium-free artificial seawater (CaFASW). The suspension was filtered throuah a double layer of cheese-cloth and washed three or four tl’mes in CaFASW using a hand centrifuge to remove the I-MeAproducing fotficlecells. Dense oo&te suspension was used to obtain “plasma membrane-rich fraction” as described by Dome er al. (1978). The adenylate cyclase activity was measured as in Tkachuk and Baldenkov (1978). Assays were routinely performed in 50~1, containing 2mM ATPI SmM MgCl,. 20 mM Tris--HCi, pH 7.5. 10 mM theophylline, plus an ATP system (5 mM phosphocreatinine, 3.2 regenerating unit/assay creative phosphokinase). The reaction was initiated by adding 50~1 of protein and continued for 20min at 20°C. It was stopped by boiling and subsequent cooling. Assays were centrifuged for 10 min at 3000 rpm and the supernatant was used to determine the amount of the resultant c-AMP. as described by Jihnan (1970). The content of protein optima1 for determjnation of adenylate cyclase activity was IO-i~~g~assay. in our experiments the concentration of protein was 20.-30 pg/assay. All assays were done in triplicate and the interassay standard error was ~5%.
tissues
which are known to be mediators of the m5noaminergic system (Cottrell and Pentreath, 1970; Huet and Franquinet, 1981). The seasonal dynamics of the level of these hormones was investigated during the reproductive season and from the results obtained it was inferred that the monoaminergic system can participate in the regulation of gametogenesis (Khotim~henko and Deridovich 1988). Many of the physiological actions of biogenic monoamines are ~ondiiioned by the activation of adenylate cyclase which leads to intracellular accumulation of cyclic 3,5-AMP. The intracellular c-AMP regufates synthesis of many organic components of the cell and enzyme activity. The role of c-AMP in echinoderm gametes is still not clear. It has been suggested that cyclic nucleotides can regulate sperm motility, enzyme productivity in eggs and energetic metabolism of sperms and eggs (Garbers et al., 1980; Kopf. 1977; Lee, 1976; Nath, 1973). Also, the induction of meiosis involves a depression in CAMP tevel in starfish 55cytes {Neijer and Zarutskie, 1987). The hormone-sensitive adenylate cyclase has been described in fairly great detail in membranes of the somatic ceils. considerably less is known about components of the system of cyclic nucleotides of the sex cells (Mourelle et al., 1984; Finidory, 1982; Chiba, 1989; Capasso, 1987, 1989) Such investigations can, in our opinion, be useful for understanding ovo- and spermatogenesis. The present work is the first attempt to study the functional characteristics of hormone-sensitive adenylate cyclase system of oocytes of the starfish
should be addressed.
Abb~e~iutioff used: G, guanine nucl~ot~de-binding protein,
METHODS
RESULTS
The kinetic parameters (K, and V,,,) were determined using MgATP as substrates. Cyclase activity followed Michaelis kinetics with K,, = 0.25 mM, V,,, = 2-3 pmoles cAMP/mg protein/min. The presence of Mn’+ had a stimulatory effect on the adenylate cyclase in the starfish oocyte membranes (Fig. 1). Adenylate cyclase was activated by NaF, GTP, cholera toxin and forskohn (Table I). NaF showed a maximal stimulatory effect at a concentration of lOmM (assay). GTP enhanced the enzyme activity only at high concentrations of 10-5-10-4M. The
379
N. E.
380
LAMASHand
Yu S. KHOTIMCHENKO
Catecholamine concentration Fig. 1.
Effect of increasing concentrations of MnCl, on the adenylate cyclase of starfish oocyte.
starfish oocyte cyclase responds to stimulation by pretreatment with cholera toxin. Specific activator of adenylate cyclase-foreskolin produced an effect at 10-5-10-4 M and lower concentrations of this substance proved ineffective. Catecholamines (adrenalin, noradrenalin and dopamine) stimulated adenylated cyclase activity. Maximal activation by adrenalin and noradrenalin was obtained at lo-’ M. Stimulatory effect of dopamine in low concentrations was the greatest (Fig. 2). Serotonin in concentrations of 10-5-10-4M had no effect on adenylate cyclase activity.
The presence of noradrenalin and dopamine in the starfish gonads and the change in the sensitivity of oocytes to these substances during gametogenesis allow us to assume that catecholamines may influence the successful course of events in ovogenesis. As it was noted, catecholamines produce their regulatory effect on the functional activity of the target cells via the adenylate cyclase system. Proceeding from this, we have made an attempt to determine whether in plasma membranes of starfish oocytes, there is a hormone-sensitive adenylate cyclase similar to those described for other cells. According to the model proposed by Lefkowitz (1983) this system consists of three interacting subunits-receptory, regulatory and catalytic. By its properties such as the use of a MgATP as a substratum and the ability to be activated by Mn 2+, the catalytic subunit of the adenylate cyclase system of starfish oocyte membranes is not different from that in Xenopus laevis oocytes (Finidory et al., 1982) sea urchin Lytechinus pectus sperm (Mourell et al., 1984) and invertebrate somatic cells. In our view, an S-like character of the curve describing the dependence of the basal enzyme activity on the concentration of Mn2+ can be explained by the fact that the enzyme binds free Mn2+ addition Table I. Addition None
NaF Forskolin GTF Cholera toxin
IO 2 10-S 10-h 10-5 lWflg/ml
(pm&s
of
Activity cAMP/mg prot/min)
0.89 + 42.51 + 7.38 f 15.82* 5.42 + 4.82 z
0.09 3.21 0.82 I.10 0.20 0.06
(
M
)
Fig. 2. Adenylate cyclase stimulation by various catecholamines. m-control, m-adrenalin, q-noradrenalin, qAopamine. Membranes were assayed in the presence of the indicated
factors.
to MnATP. Which of the adenylate cyclase complex has sites for the cations has not yet been determined. Hanski (1981) and Sternweis (1981) believe that merely one of the subunits of G-protein in the erythrocyte plasmolemma possesses such an ability, whereas Ferguson (1982) does not rule out the possibility that these sites can be located on the catalytic subunit also. In studying the regulatory subunit, we used as functional markers NaF, guanine nucleotides and cholera toxin. In our experiments, guanyl nucleotides stimulated the adenylate cyclase only at high concentrations. This may be due to a strong GTP-ase activity of the regulatory subunit (G-proteins). Thus, after incubation of membranes of Xenopus laevis oocytes with cholera toxin, the stimulatory effect is achieved by the use of GTP (Finidori, 1982). Since activation can be effected by guanine nucleotides, NaF and cholera toxin, thus demonstrating the presence of a functioning guanine nucleotide binding protein (regulatory subunit). It does not differ from regulatory components of the adenylate cyclase system in both somatic and sex cells. The most complicated problem is the characterization of the receptory subunit of adenylate cyclase, because major differences found among membraneassociated adenylate cyclases concern primarily this subunit (Pertseva et al., 1987). Recent studies suggest the presence of neurotransmitter receptors in the oocyte membrane of echinoderms, amphibians, birds and rats which disappear after maturation and/or fertilization. At the same time, adenylate cyclase activity in the plasmolemma also disappears (Kusano et al., 1978, 1982; Eusebi et al., 1984; Rostomyan et al., 1985; Buznikov, 1983). However, these receptors have not yet been identified probably because of their small number. Catecholamines can produce their action via adrenoreceptors of the p-type (Levitzki, 1978). In this case, according to the degree of their effect on adenylate cyclase, they can be arranged into isoproterenol > adrenalin > the following range: noradrenalin. As shown in the present work, the adenylate cyclase of starfish oocytes is equally sensitive to adrenalin and noradrenaline, while dopamine in low concentrations (IO-*-lo-’ M) caused the maximal activation of the enzyme. This finding can be evidence for the absence of typical P-adrenergic receptors associated with adenylate cyclase. It is
Adenyl cyclase in starfish oocytes known that the effect of catecholamines may be mediated by other receptors, as it was shown for the nerve tissue of insects (Sieghart et al., 1976) and muscles of molluscs (Pertseva et al., 1987). In the latter case, serotonin receptors were assumed to be mediators. However, in our experiments, serotonin did not influence cyclase activity. It is possible that in the starfish oocyte membranes there can be dopamine receptor-like structures such as those described for sea urchin oocyte membranes (Capasso, 1987). This is confirmed by the results from in vitro experiments with gonad fragments of the starfish Asterius amurensis. After the addition of dopamine to the incubation medium, the c-AMP level in the ovaries increased as well as increased the amount of the precipitate of the cytochemical reaction that identifies the adenylate cyclase on the outside of the membrane. Haloperidol, an inhibitor of the dopamine receptors, eliminated the effect of dopamine (Deridovich et al., 1988). Also, we have reported that in the ectoneural and endoneural regions of the central nervous system of A. amurensis, dopamine and noradrenalin were found in concentrations of 4.32 pg/g wet weight and 2.86 pg/g wet weight, while serotonin and adrenaline were either absent or present in very small amounts (Khotimchenko et al., 1988, 1989). Only special studies are required to answer the question as to which receptor type is involved in adenylate cyclase activity in the starfish oocyte membranes. SUMMARY
The adenylate cyclase system in the membrane oocyte of Asterias amurensis has been studied. Starfish cyclase is activated by guanine nucleotides, fluoride, forskolin, cholera toxin and Mn’+. Only dopamine out of the tested biogenic amines (adrenalin, noradrenalin, serotonin) stimulates the adenylate cyclase activity by low (lo-* M) concentrations, which agrees with the fact that this neurohormone is a main neuromediator in starfish. It was suggested that the membrane oocytes have receptor-like structures which are sensitive to dopamine. We believe that in the starfish oocyte membrane there is a hormone-sensitive adenylate cyclase similar to those described for other cells. Acknowledgements-We
thank Dr L. A. Kusnetsova for her skilful and methodical assistance. REFERENCES
Buznikov G. A., Malchenko L. A. and Rakic L. (1984) Sensitivity of starfish oocytes and whole, half and enucleated embryos to cytotoxic neuropharmacological drugs. Comp. Biochem. Physiol. 78C, 197-201.
Capasso A., Parisi E., De Prisco P., De Petrocellis B. (1987) Catecholamine secretion and adenylate cyclase activation in sea urchin eggs. Cell Biol. Int. Rep. 11, 457463. Capasso A., Creti P., De Prisco P. P. and Parisi E. (1988) Role of dopamine and indolamine derivatives in the regulation of the sea urchin adenylate cyclase. Biochem. biophys. Res. Commun. 154, 758-764. Chiba K. and Hoshi M. (1989) Pertussis toxin bloks Imethyladenine-induced
381
382
N. E. LAMASH and Yu S. KHOTIMCHENKO
P. (1987) Star&h oocyte Meijer L. and Zarutskie maturation: I-methyladenine triggers a drop of CAMP concentration released to the hormone-dependent period. Devl Biol. 121, 306-315. Nath J. and Rebhun L. I. (1973) Studies on cyclic AMP levels and phosphodiesterase activity in developing sea urchin eggs. Expl Cell Res. 77, 319-322. Pertseva M. N. and Soltitskaya L. P. (1987) Properties of the adenylate cyclase system in the muscular-tissue of mollusk. Anodonta cy,gnea. J. Biochem. (Ukraine) 59. _14-20. Rostomyan M. A., Abramyan Y. S., Buznikov G. A., Gusareva E. V. (1985) Electron cytochemical detection of
adenylate cyclase in embryos of sea urchin. Cytology 27, 877-881. Sieghart W., Leitich H., Karobath M. (1976) Subcellular distribution of dopamine-sensitive adenylate cyclase. Brain Res. 109, 418422. Sternweis P. C., Northrup J. K., Smigel M. D., Jilman A. G. (1981) The regulatory component of adenylate cyclase: purification and _ properties. J. biol. Chem. 256, _ <1,517-l-1,526. Tkachuk V. A.. Baldenkov G. N. (1978) Isolation. nurification and characterization of regulatory properies of adenylate cyclase from rabbit heart. Biochemistry 43, 1097-l 110.