18 results on '"R., DE STASIO"'
Search Results
2. Analisi del contenuto di 'metalli traccia' e dei meccanismi molecolari che ne controllano l’omeostasi in Anfibi e Rettili del Parco del Matese
- Author
-
M. RIGGIO, L. BORRELLI, R. DE STASIO, S. FILOSA, SCUDIERO, ROSARIA, G. ODIERNA F. M. GUARINO, M., Riggio, Scudiero, Rosaria, L., Borrelli, R., DE STASIO, Filosa, Silvana, and S., Filosa
- Subjects
rettili ,anfibi ,metalli traccia - Published
- 2002
3. Effects of cadmium on retinal development in lizard embryo: A molecular and morphological study
- Author
-
Lucia Borrelli, Rosaria Scudiero, Silvana Filosa, Palma Simoniello, R. De Stasio, Francesca Trinchella, Chiara Maria Motta, Simoniello, P, Trinchella, F, Borrelli, L, De Stasio, R, Motta, CHIARA MARIA, Filosa, Silvana, and Scudiero, Rosaria
- Subjects
Cadmium ,Physiology ,Lizard ,chemistry.chemical_element ,Embryo ,Retinal ,Anatomy ,Biology ,Biochemistry ,Cell biology ,chemistry.chemical_compound ,chemistry ,biology.animal ,Molecular Biology - Published
- 2009
4. Responsiveness of adenylate cyclase to pituitary gonadotropins and evidence of a hormone-induced desensitization in the lizard ovary
- Author
-
V. Bovenzi, Elio Parisi, R. De Stasio, Silvana Filosa, Lucia Borrelli, L., Borrelli, R., DE STASIO, V., Bovenzi, E., Parisi, and Filosa, Silvana
- Subjects
Intracellular Fluid ,Male ,endocrine system ,medicine.medical_specialty ,medicine.drug_class ,media_common.quotation_subject ,Stimulation ,Biology ,Cyclase ,Endocrinology ,Internal medicine ,Follicular phase ,Testis ,medicine ,Cyclic AMP ,Animals ,Ovulation ,media_common ,Cell Membrane ,Ovary ,Lizards ,Progesterone secretion ,DNA ,Fertility Agents, Female ,Luteinizing Hormone ,Blotting, Southern ,Gonadotropins, Pituitary ,Autoradiography ,Animal Science and Zoology ,Female ,Gonadotropin ,Follicle Stimulating Hormone ,DNA Probes ,Cyclase activity ,hormones, hormone substitutes, and hormone antagonists ,Hormone ,Adenylyl Cyclases - Abstract
Gonadotropins (FSH and LH) affect several mammalian gonadal functions. In particular, FSH stimulates oogonial proliferation and oocyte growth, while LH regulates ovulation and progesterone secretion. In lacertilian reptiles, gonadal function is also regulated by pituitary gonadotropins, but which hormone controls ovarian activities and the mechanisms of action are unknown. The present study aimed to clarify mechanisms of action of pituitary gonadotropins on the ovary of Podarcis sicula (Lacertilia). The data demonstrate that mammalian gonadotropins FSH and LH produce a threefold stimulation of adenylate cyclase activity in follicular membranes, while hCG and TSH are less effective, causing a twofold increase in adenylate cyclase activity. Neurotrasmitters such as dopamine, serotonin, and catecholamines have no effect on enzyme activity. The action of mammalian FSH and LH on the ovary mimics the effect of homologous hormones: in lizard ovaries incubated in vitro in the presence of isolated homologous pituitary glands, the intracellular cAMP level increased by 50% with respect to control ovaries. Mammalian gonadotropins appear homologous to lizard gonadotropin(s): Southern blot analyses show that the lizard genome contains nucleotide sequences homologous to those encoding for mammalian βFSH and βLH. Both homologous and heterologous desensitization of adenylate cyclase activity occurs in the lizard ovary. In fact, responsiveness of adenylate cyclase to gonadotropin stimulation is abolished in animals 2 hr after in vivo treatment with FSH. Sensitivity to gonadotropin stimulation is restored 2 weeks after the beginning of the in vivo treatment. Desensitization was also observed in ovaries incubated in vitro with mammalian FSH or with isolated pituitary glands.
- Published
- 1997
5. Seasonal-dependent effect of temperature on the response of adenylate cyclase to FSH stimulation in the oviparous lizard, Podarcis sicula
- Author
-
Chiara Maria Motta, R. De Stasio, Elio Parisi, Silvana Filosa, and Lucia Borrelli
- Subjects
medicine.medical_specialty ,endocrine system ,medicine.drug_class ,Endocrinology, Diabetes and Metabolism ,media_common.quotation_subject ,Stimulation ,Biology ,Follicle-stimulating hormone ,Endocrinology ,Internal medicine ,medicine ,Seasonal breeder ,Animals ,Ovulation ,media_common ,Analysis of Variance ,Reproduction ,Ovary ,Temperature ,Lizards ,Oocytes ,Female ,Seasons ,Gonadotropin ,Follicle Stimulating Hormone ,Oviparity ,Cyclase activity ,Hormone ,Adenylyl Cyclases - Abstract
The study of environmental factors affecting vertebrate reproduction has long interested both developmental and evolutionary biologists. Although photoperiod has been considered to be an important environmental parameter for vertebrates such as birds, temperature is probably a primary external factor responsible for reproductive cyclicity in reptiles. In spite of the progress made in the understanding of reptilian reproductive strategies and adaptations, much remains to be learned about the interplay between endocrine physiological factors, such as hormones, and environmental parameters. In this report, we have examined the effects of in vivo administered FSH on oocyte recruitment during the most significant periods of the reproductive cycle of the lizard, Podarcis sicula. The results show that when FSH is administered in proximity to the reproductive period, it stimulates oocyte growth and ovulation; when the hormone is administered at the beginning of the winter stasis it affects ovarian activity without inducing ovulation. Ovarian adenylate cyclase activity is moderately sensitive to in vitro FSH stimulation during the pre- and post-reproductive periods. The sensitivity to hormone stimulation increases significantly during the reproductive period and winter stasis. We have also tested the hypothesis that environmental temperature affects the responsiveness of ovarian adenylate cyclase to FSH stimulation. For such a purpose, we exposed animals to 28 degrees C or 4 degrees C in different periods of the ovarian cycle. The results show that, whenever the temperature applied mimics the thermal regime of the coming season, adenylate cyclase sensitivity to FSH shifts towards levels that anticipate the natural responsiveness.
- Published
- 2000
6. A fast and sensitive method for detecting specific viral RNA in mammalian cells
- Author
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P R De Stasio, Milton W. Taylor, and U Paeratakul
- Subjects
Simplexvirus ,food.ingredient ,Transcription, Genetic ,viruses ,Immunology ,Biology ,Microbiology ,Cell Line ,Nucleic acid thermodynamics ,food ,Interferon ,Viral entry ,Virology ,Viral structural protein ,medicine ,Animals ,Humans ,Encephalomyocarditis virus ,Vero Cells ,Regulation of gene expression ,fungi ,Nucleic Acid Hybridization ,food and beverages ,Gene Expression Regulation ,Glutaral ,Cell culture ,Insect Science ,DNA, Viral ,Vero cell ,RNA, Viral ,Interferons ,Research Article ,medicine.drug - Abstract
A quick and sensitive method to quantitate viral RNA synthesis has been developed. Utilizing glutaraldehyde to fix infected cells onto nitrocellulose paper, viral RNA can be probed directly in situ. Viral message can be detected from as few as 10(4) infected cells. This technique can be used to study viral gene expression and can be adapted to screen the activity of antiviral agents such as interferon.
- Published
- 1988
7. In situ amplification of viral signal in infected samples applied directly to nitrocellulose membranes
- Author
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P R, De Stasio, K J, Etchberger, U, Paeratakul, and M W, Taylor
- Subjects
Molecular Probes ,Virology ,DNA, Viral ,Viruses ,Collodion ,Nucleic Acid Hybridization ,RNA, Viral ,Filtration ,Biotechnology - Abstract
A method for the amplification of viral signal present in infected samples is described. Viral suspensions are spotted on nitrocellulose paper, and immediately afterwards an adequate amount of a permissive cell line is added. The nitrocellulose filter is then incubated overnight, fixed and hybridized to labeled viral probes. The technique is extremely fast, reproducible and inexpensive, and may be readily applicable to the clinical diagnosis of many viral diseases.
- Published
- 1989
8. Isolation and molecular cloning of a fast-growing strain of human hepatitis A virus from its double-stranded replicative form
- Author
-
N del Grosso, A. M. Degener, M. G. Martiniello, Aldo Venuti, A. M. Patti, P. Pagnotti, C Di Russo, M. Midulla, P R De Stasio, and Franco Maria Ruggeri
- Subjects
viruses ,Immunology ,Biology ,Molecular cloning ,Virus Replication ,Microbiology ,Genome ,Virus ,Plasmid ,Cytopathogenic Effect, Viral ,Viral entry ,Virology ,Complementary DNA ,Viral structural protein ,Animals ,Humans ,Hepatovirus ,Cloning, Molecular ,Antigens, Viral ,RNA, Double-Stranded ,Genetics ,Base Sequence ,Insect Science ,Helper virus ,Protein Biosynthesis ,RNA, Viral ,Poly A ,Research Article - Abstract
A fast-growing strain of human hepatitis A virus was selected and characterized. The virus has the unusual property of developing a strong cytopathic effect in tissue culture in 7 to 10 days. Sequences of the viral genome were cloned into recombinant plasmids with the double-stranded replicative form as a template for the reverse transcription of cDNA. Restriction analysis and direct sequencing indicate that this strain is different from that described by Ticehurst et al. (Proc. Natl. Acad. Sci. USA 80:5885-5889, 1983) in the region that presumptively codes for the major capsid protein VP1, but both isolates have conserved large areas of homology in the untranslated 5'-terminal sequences of the genome.
- Published
- 1985
9. A sensitive method to titer interferons
- Author
-
P R, De Stasio, K, Reichenba, and M W, Taylor
- Subjects
Cytopathogenic Effect, Viral ,Virology ,Nucleic Acid Hybridization ,RNA, Viral ,Interferons ,DNA Probes - Published
- 1988
10. Evolutionary fate of duplicate genes encoding aspartic proteinases. Nothepsin case study
- Author
-
Elio Parisi, Francesca Trinchella, Rosaria Scudiero, Roberta De Stasio, Silvana Filosa, Marilisa Riggio, Lucia Borrelli, L., Borrelli, R., DE STASIO, Filosa, Silvana, E., Parisi, M., Riggio, Scudiero, Rosaria, and F., Trinchella
- Subjects
Genetics ,Concerted evolution ,Base Sequence ,Gene duplication, aspartic proteinases, cathepsin, nothepsin, molecule evolution, gene gain and loss ,Molecular Sequence Data ,Fishes ,Pair-rule gene ,Lizards ,General Medicine ,Paralogous Gene ,Biology ,Cathepsin D ,Evolution, Molecular ,Amino Acid Substitution ,Gene Duplication ,Gene duplication ,Gene cluster ,Animals ,Aspartic Acid Endopeptidases ,Gene family ,Neofunctionalization ,Amino Acid Sequence ,Phylogeny ,Functional divergence - Abstract
Gene duplication is considered an important evolutionary mechanism leading to new gene functions. According to the classical model, one gene copy arising from gene duplication retains the ancestral function, whilst the other becomes subject to directional selection for some novel functions. Hence, according to this model, long-term persistence of two paralogous genes is possible only with the acquisition of functional innovation. In the absence of neofunctionalization, one of the duplicate genes may be lost following accumulation of deleterious mutations, ultimately leading to the loss of function. Recently, new mechanisms have been proposed according to which both paralogs are maintained without apparent neofunctionalization. In this paper we describe the molecular evolution of the aspartic proteinase gene family, with particular regard for the nothepsin gene, a sex- and tissue-specific form of aspartic proteinase active in fish. The finding of nothepsin in a reptile is indicative of the presence of this gene in organisms other than fish. However, the failure to find any nothepsin-like gene in avian, murine and human genome suggests that the gene has been lost in certain lineages during evolution. At variance with piscine nothepsin expressed exclusively in female liver under the estrogens action, the reptilian counterpart lacks both tissue and sex specificity, as it is constitutively expressed in different tissues of male and female specimens. The expression of the nothepsin gene in fish and lizard is accompanied by the expression of a paralogous gene encoding for cathepsin D. Functional divergence analysis indicates that cathepsin D accumulated amino acid substitutions, whereas nothepsin retained most of the ancestral functions. Phylogenetic analysis shows a preponderance of replacement substitutions compared to silent substitutions in the branch leading to the cathepsin D clade, whilst nothepsin evolves under negative selection. To explain the loss of the nothepsin gene in certain lineages, we propose a model that takes into account the complementary degenerative mutations occurring in regulatory elements of the promoter regions of the two genes. According to this model, gene loss occurs whenever the two genes acquire the same expression pattern. The coexistence of cathepsin D and nothepsin is explained in terms of metabolic cooperation of the two enzymes.
- Published
- 2006
11. Aspartic proteinases and vitellogenesis in oviparous vertebrates
- Author
-
SCUDIERO, ROSARIA, FILOSA, SILVANA, DE STASIO R, BORRELLI L, RIGGIO M., S.G. PANDALAI ED, Scudiero, Rosaria, R., DE STASIO, L., Borrelli, Filosa, Silvana, M., Riggio, Pandalai S.G., DE STASIO, R, Borrelli, L, and Riggio, M.
- Subjects
Aspartic proteinases ,VITELLOGENESIS - Published
- 2002
12. Crosstalk between EGFR and extranuclear steroid receptors.
- Author
-
Migliaccio A, Castoria G, Di Domenico M, Ciociola A, Lombardi M, De Falco A, Nanayakkara M, Bottero D, De Stasio R, Varricchio L, and Auricchio F
- Subjects
- Androgen Receptor Antagonists, Cell Line, Tumor, Cell Nucleus metabolism, Enzyme Activation, Epidermal Growth Factor pharmacology, ErbB Receptors agonists, Estradiol analogs & derivatives, Estradiol pharmacology, Estrogen Antagonists pharmacology, Estrogen Receptor alpha antagonists & inhibitors, Female, Fulvestrant, Humans, Male, Phosphorylation, Receptor Cross-Talk, Receptors, Steroid antagonists & inhibitors, Receptors, Steroid metabolism, Signal Transduction, Tyrosine metabolism, Up-Regulation, src-Family Kinases antagonists & inhibitors, src-Family Kinases metabolism, Breast Neoplasms metabolism, ErbB Receptors metabolism, Estrogen Receptor alpha metabolism, Prostatic Neoplasms metabolism, Receptors, Androgen metabolism
- Abstract
Epidermal growth factor (EGF) stimulates DNA synthesis and cytoskeletal rearrangement in human breast cancer (MCF-7) and human prostate cancer (LNCaP) cells. Both effects are inhibited by estrogen (ICI 182,780) and androgen (Casodex) antagonists. This supports the view that crosstalk exists between EGF and estradiol (ER) and androgen (AR) receptors and suggests that these receptors are directly involved in the EGF action. Our recent work shows that EGF stimulates ER phosphorylation on tyrosine and promotes the association of a complex between EGFR, AR/ER, and the kinase Src. The complex assembly triggers Src activity, epidermal growth factor receptor (EGFR) phosphorylation on tyrosine, and the EGF-dependent signaling pathway activation. In these cells, the AR/ER/Src complex is required for the EGF action, as the growth factor effects are abolished upon receptor silencing by specific SiRNAs and steroid antagonists or Src inhibition by the kinase inhibitor PP2.
- Published
- 2006
- Full Text
- View/download PDF
13. Evolutionary fate of duplicate genes encoding aspartic proteinases. Nothepsin case study.
- Author
-
Borrelli L, De Stasio R, Filosa S, Parisi E, Riggio M, Scudiero R, and Trinchella F
- Subjects
- Amino Acid Sequence, Amino Acid Substitution, Animals, Base Sequence, Molecular Sequence Data, Phylogeny, Aspartic Acid Endopeptidases genetics, Cathepsin D genetics, Evolution, Molecular, Fishes genetics, Gene Duplication, Lizards genetics
- Abstract
Gene duplication is considered an important evolutionary mechanism leading to new gene functions. According to the classical model, one gene copy arising from gene duplication retains the ancestral function, whilst the other becomes subject to directional selection for some novel functions. Hence, according to this model, long-term persistence of two paralogous genes is possible only with the acquisition of functional innovation. In the absence of neofunctionalization, one of the duplicate genes may be lost following accumulation of deleterious mutations, ultimately leading to the loss of function. Recently, new mechanisms have been proposed according to which both paralogs are maintained without apparent neofunctionalization. In this paper we describe the molecular evolution of the aspartic proteinase gene family, with particular regard for the nothepsin gene, a sex- and tissue-specific form of aspartic proteinase active in fish. The finding of nothepsin in a reptile is indicative of the presence of this gene in organisms other than fish. However, the failure to find any nothepsin-like gene in avian, murine and human genome suggests that the gene has been lost in certain lineages during evolution. At variance with piscine nothepsin expressed exclusively in female liver under the estrogens action, the reptilian counterpart lacks both tissue and sex specificity, as it is constitutively expressed in different tissues of male and female specimens. The expression of the nothepsin gene in fish and lizard is accompanied by the expression of a paralogous gene encoding for cathepsin D. Functional divergence analysis indicates that cathepsin D accumulated amino acid substitutions, whereas nothepsin retained most of the ancestral functions. Phylogenetic analysis shows a preponderance of replacement substitutions compared to silent substitutions in the branch leading to the cathepsin D clade, whilst nothepsin evolves under negative selection. To explain the loss of the nothepsin gene in certain lineages, we propose a model that takes into account the complementary degenerative mutations occurring in regulatory elements of the promoter regions of the two genes. According to this model, gene loss occurs whenever the two genes acquire the same expression pattern. The coexistence of cathepsin D and nothepsin is explained in terms of metabolic cooperation of the two enzymes.
- Published
- 2006
- Full Text
- View/download PDF
14. Relationship between adenylate cyclase sensitivity to follitropin and FSH receptor mRNA expression in the ovary of the lizard Podarcis sicula.
- Author
-
Borrelli L, De Stasio R, Parisi E, and Filosa S
- Subjects
- Animals, Female, Follicle Stimulating Hormone pharmacology, Lizards, Ovary drug effects, Ovary enzymology, Adenylyl Cyclases metabolism, Follicle Stimulating Hormone metabolism, Gene Expression, Ovary metabolism, RNA, Messenger, Receptors, FSH genetics
- Abstract
In mammals, gonadal functions are regulated by two pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), that interact with gonadal membrane receptors to activate adenylate cyclase. In comparison to mammalian systems, in squamate reptiles a reduced amount of information exists on gonadotropins and their related receptors. This study is aimed at clarifying if, in the lizard Podarcis sicula, the ovarian sensitivity to FSH is correlated to the reproductive cycle and to the expression of membrane receptors involved in the hormone recognition. The results demonstrate that the ovarian adenylate cyclase responsiveness to FSH parallels ovarian functions, being maximal during the ovulatory period. The ovarian sensitivity to FSH is also related to oocyte growth and vitellogenesis. Northern blot analyses reveal that the FSH receptor mRNA is maximally expressed in vitellogenic oocytes during the reproductive period. These results suggest that, in lizard ovary, hormone activation of adenylate cyclase is mediated by de novo synthesis of receptors specifically involved in FSH recognition. In lizards treated in vivo with FSH during the pre-ovulatory period, adenylate cyclase becomes refractory to further FSH stimulation 2 hr after treatment, but sensitivity to the hormone is restored after 2 weeks. Nevertheless, while the restored level of activity never exceeds that observed during the nonreproductive period, the expression level of FSH receptor mRNAs is significantly enhanced in these animals. These results suggest that in lizard the processes that regulate ovarian growth, vitellogenesis, and ovulation are controlled by a complex network of signals including gonadotropin, FSH receptor expression, and adenylate cyclase., (Copyright 2002 Wiley-Liss, Inc.)
- Published
- 2002
- Full Text
- View/download PDF
15. Molecular cloning, sequence and expression of follicle-stimulating hormone receptor in the lizard Podarcis sicula.
- Author
-
Borrelli L, De Stasio R, Parisi E, and Filosa S
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Blotting, Northern, Cloning, Molecular, DNA, Complementary chemistry, DNA, Complementary genetics, Female, Gene Expression, In Situ Hybridization, Molecular Sequence Data, Ovary metabolism, Phylogeny, RNA genetics, RNA metabolism, Sequence Analysis, DNA, Tissue Distribution, Lizards genetics, Receptors, FSH genetics
- Abstract
The present paper reports the full nucleotide sequence of a cloned cDNA prepared from RNA of lizard ovaries. The open reading frame consists of 2019 nucleotides, which encodes a protein of 673 amino acids belonging to the G protein-coupled receptor superfamily with a large extracellular N-terminal domain involved in hormone recognition. The transmembrane domain ends with a short intracytoplasmic COOH-terminal domain involved in effector activation. Phylogenetic analysis showed that the lizard receptor belongs to the family of follicle-stimulating hormone (FSH) receptors. The hydrophobicity profile is similar to that observed for mammalian and avian FSH receptors. Northern blot analysis of total RNA revealed that the FSH receptor is expressed at high levels in the ovary. In situ hybridization experiments demonstrate that FSH receptor mRNA is specifically localized within the small cells of the follicular epithelium surrounding the oocyte.
- Published
- 2001
- Full Text
- View/download PDF
16. Seasonal-dependent effect of temperature on the response of adenylate cyclase to FSH stimulation in the oviparous lizard, Podarcis sicula.
- Author
-
Borrelli L, De Stasio R, Motta CM, Parisi E, and Filosa S
- Subjects
- Analysis of Variance, Animals, Female, Follicle Stimulating Hormone pharmacology, Lizards metabolism, Oocytes drug effects, Oocytes growth & development, Ovary drug effects, Reproduction physiology, Adenylyl Cyclases metabolism, Lizards physiology, Ovary enzymology, Seasons, Temperature
- Abstract
The study of environmental factors affecting vertebrate reproduction has long interested both developmental and evolutionary biologists. Although photoperiod has been considered to be an important environmental parameter for vertebrates such as birds, temperature is probably a primary external factor responsible for reproductive cyclicity in reptiles. In spite of the progress made in the understanding of reptilian reproductive strategies and adaptations, much remains to be learned about the interplay between endocrine physiological factors, such as hormones, and environmental parameters. In this report, we have examined the effects of in vivo administered FSH on oocyte recruitment during the most significant periods of the reproductive cycle of the lizard, Podarcis sicula. The results show that when FSH is administered in proximity to the reproductive period, it stimulates oocyte growth and ovulation; when the hormone is administered at the beginning of the winter stasis it affects ovarian activity without inducing ovulation. Ovarian adenylate cyclase activity is moderately sensitive to in vitro FSH stimulation during the pre- and post-reproductive periods. The sensitivity to hormone stimulation increases significantly during the reproductive period and winter stasis. We have also tested the hypothesis that environmental temperature affects the responsiveness of ovarian adenylate cyclase to FSH stimulation. For such a purpose, we exposed animals to 28 degrees C or 4 degrees C in different periods of the ovarian cycle. The results show that, whenever the temperature applied mimics the thermal regime of the coming season, adenylate cyclase sensitivity to FSH shifts towards levels that anticipate the natural responsiveness.
- Published
- 2000
- Full Text
- View/download PDF
17. Isolation, characterization and molecular cloning of cathepsin D from lizard ovary: changes in enzyme activity and mRNA expression throughout ovarian cycle.
- Author
-
De Stasio R, Borrelli L, Kille P, Parisi E, and Filosa S
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cathepsin D isolation & purification, Cathepsin D metabolism, Cloning, Molecular, DNA, Complementary, Female, Gene Expression, Gonads, Humans, Molecular Sequence Data, RNA, Messenger, Reproduction, Sequence Homology, Amino Acid, Cathepsin D genetics, Lizards, Ovary enzymology
- Abstract
During vitellogenesis, the oocytes of oviparous species accumulate in the cytoplasm a large amount of proteic nutrients synthetized in the liver. Once incorporated into the oocytes, these nutrients, especially represented by vitellogenin (VTG) and very low-density lipoprotein (VLDL), are cleaved into a characteristic set of polypeptides forming yolk platelets. We have studied the molecular mechanisms involved in yolk formation in a reptilian species Podarcis sicula, a lizard characterized by a seasonal reproductive cycle. Our results demonstrate the existence in the lizard ovary of an aspartic proteinase having a maximal activity at acidic pH and a molecular mass of 40 kDa. The full-length aspartic proteinase cDNA produced from total RNA by RT-PCR is 1,442 base pairs long and encodes a protein of 403 amino acids. A comparison of the proteic sequence with aspartic proteinases from various sources demonstrates that the lizard enzyme is a cathepsin D. Lizard ovarian cathepsin D activity is maximal in June, in coincidence with vitellogenesis and ovulation, and is especially abundant in vitellogenic follicles and in eggs. Ovarian cathepsin D activity can be enhanced during the resting period by treatment with FSH in vivo. Northern blot analysis shows that cathepsin D mRNA is exceedingly abundant during the reproductive period, and accumulates preferentially in previtellogenic oocytes.
- Published
- 1999
- Full Text
- View/download PDF
18. Responsiveness of adenylate cyclase to pituitary gonadotropins and evidence of a hormone-induced desensitization in the lizard ovary.
- Author
-
Borrelli L, De Stasio R, Bovenzi V, Parisi E, and Filosa S
- Subjects
- Animals, Autoradiography, Blotting, Southern, Cell Membrane drug effects, Cell Membrane metabolism, Cyclic AMP metabolism, DNA analysis, DNA Probes chemistry, Female, Follicle Stimulating Hormone genetics, Follicle Stimulating Hormone pharmacology, Intracellular Fluid metabolism, Luteinizing Hormone genetics, Luteinizing Hormone pharmacology, Male, Ovary cytology, Ovary drug effects, Testis metabolism, Adenylyl Cyclases metabolism, Fertility Agents, Female pharmacology, Gonadotropins, Pituitary pharmacology, Lizards, Ovary enzymology
- Abstract
Gonadotropins (FSH and LH) affect several mammalian gonadal functions. In particular, FSH stimulates oogonial proliferation and oocyte growth, while LH regulates ovulation and progesterone secretion. In lacertilian reptiles, gonadal function is also regulated by pituitary gonadotropins, but which hormone controls ovarian activities and the mechanisms of action are unknown. The present study aimed to clarify mechanisms of action of pituitary gonadotropins on the ovary of Podarcis sicula (Lacertilia). The data demonstrate that mammalian gonadotropins FSH and LH produce a threefold stimulation of adenylate cyclase activity in follicular membranes, while hCG and TSH are less effective, causing a twofold increase in adenylate cyclase activity. Neurotransmitters such as dopamine, serotonin, and catecholamines have no effect on enzyme activity. The action of mammalian FSH and LH on the ovary mimics the effect of homologous hormones: in lizard ovaries incubated in vitro in the presence of isolated homologous pituitary glands, the intracellular cAMP level increased by 50% with respect to control ovaries. Mammalian gonadotropins appear homologous to lizard gonadotropin(s): Southern blot analyses show that the lizard genome contains nucleotide sequences homologous to those encoding for mammalian beta FSH and beta LH. Both homologous and heterologous desensitization of adenylate cyclase activity occurs in the lizard ovary. In fact, responsiveness of adenylate cyclase to gonadotropin stimulation is abolished in animals 2 hr after in vivo treatment with FSH. Sensitivity to gonadotropin stimulation is restored 2 weeks after the beginning of the in vivo treatment. Desensitization was also observed in ovaries incubated in vitro with mammalian FSH or with isolated pituitary glands.
- Published
- 1997
- Full Text
- View/download PDF
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