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Bernard Jégou - One of the best experts on this subject based on the ideXlab platform.
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Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.
General and Comparative Endocrinology, 1999Co-Authors: Danielle Hélène Garnier, Pascal Sourdaine, Bernard JégouAbstract:Abstract Concentrations of testosterone, progesterone, Δ4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17β, 5α-androstane, 3α, 17β-diol, and 17α-hydroxy,20β-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Δ4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn–winter for androgens and progesterone, during spring for Δ4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.
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Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.
General and comparative endocrinology, 1999Co-Authors: Danielle Hélène Garnier, Pascal Sourdaine, Bernard JégouAbstract:Concentrations of testosterone, progesterone, Delta4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17beta, 5alpha-androstane, 3alpha, 17beta-diol, and 17alpha-hydroxy, 20beta-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Delta4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn-winter for androgens and progesterone, during spring for Delta4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.
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Detection of Proto-Oncogene-Like Activity in the Testis of Scyliorhinus canicula (Elasmobranchs)
Netherlands Journal of Zoology, 1994Co-Authors: Silvia Fasano, Sergio Minucci, Paolo Chieffi, D. H. Garnier, Gilda Cobellis, Bernard Jégou, Riccardo PierantoniAbstract:C-myc, c-fos, c-jun and c-mos products were localized in testis and epigonal tissue of the elasmobranch, Scyliorhinus canicula, using immunocytochemistry and Northern and Western blottings. In contrast to the situation in other vertebrates, these oncogenes do not seem to play a significant role in spermatogenesis.
Ramón Anadón - One of the best experts on this subject based on the ideXlab platform.
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GABAergic neuronal circuits in the cerebellum of the dogfish Scyliorhinus canicula (Elasmobranchs): an immunocytochemical study.
Neuroscience letters, 1995Co-Authors: Rosa Álvarez-otero, Silvia Eva Pérez, Miguel A. Rodríguez, Fátima Adrio, Ramón AnadónAbstract:The presence of GABAergic cells and fibres in the corpus cerebelli and auricles of a dogfish, Scyliorhinus canicula, was studied with immunocytochemistry. In both locations, two types of GABA-immunoreactive (GABA-ir) neurons were observed: stellate cells in the molecular layer and Golgi cells in the granular layer. Stellate cell axons gave rise to numerous GABA-ir boutons distributed throughout the molecular layer and a smaller number of boutons which contacted Purkinje cell perikarya. No GABA-ir baskets around Purkinje cells were observed. Golgi cells of the granular layer gave rise to numerous GABA-ir boutons which were located around cerebellar glomeruli. Purkinje cell perikarya and their axon terminals in the cerebellar nucleus were not GABA-immunoreactive. These findings are discussed in terms of the phylogeny of cerebellar circuits.
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Organization of Catecholaminergic Systems in the Hypothalamus of Two Elasmobranch Species, Raja undulata and Scyliorhinus canicula. A Histofluorescence and Immunohistochemical Study
Brain behavior and evolution, 1993Co-Authors: P. Molist, Isabel Rodríguez-moldes, Ramón AnadónAbstract:We examined the organization of catecholaminergic neurons in the hypothalamus of the painted ray, Raja undulata, and the small-spotted dogfish, Scyliorhinus canicula,
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Distribution of Types of Neurons in the Optic Tectum of the Small-Spotted Dogfish, Scyliorhinus canicula L. A Golgi Study
Brain behavior and evolution, 1993Co-Authors: María Jesús Manso, Ramón AnadónAbstract:The distribution of neuronal types in the six layers of the optic tectum of the small-spotted dogfish, Scyliorhinus canicula, was studied using Golgi methods. The eight types of neurons have a variabl
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The optic tectum of the dogfish Scyliorhinus canicula L.: a Golgi study.
The Journal of comparative neurology, 1991Co-Authors: M. Jesús Manso, Ramón AnadónAbstract:The optic tectum of the dogfish Scyliorhinus canicula L. was studied by using the methods of Nissl, reduced silver nitrate, Golgi-aldehyde, and Golgi-Cox. Six layers and eight types of neurons were recognized. These cell types are not restricted to one layer; in fact some are found in all six tectal layers. The types of cells found are A) monopolar, B) triangular, C) radial bipolar, D) horizontal fusiform, E) large tectal, F) small tectal, G) pyriform, and H) stellate cells. In at least six of the cell types a series of dendritic specializations can be observed, such as spines in the form of "drumsticks" and thin varicose appendages, similar to those reported previously in the optic tecta of amphibians and teleosts. The optic tectum of the dogfish shows a degree of complexity comparable to that of amphibians and teleosts.
Danielle Hélène Garnier - One of the best experts on this subject based on the ideXlab platform.
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Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.
General and Comparative Endocrinology, 1999Co-Authors: Danielle Hélène Garnier, Pascal Sourdaine, Bernard JégouAbstract:Abstract Concentrations of testosterone, progesterone, Δ4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17β, 5α-androstane, 3α, 17β-diol, and 17α-hydroxy,20β-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Δ4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn–winter for androgens and progesterone, during spring for Δ4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.
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Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.
General and comparative endocrinology, 1999Co-Authors: Danielle Hélène Garnier, Pascal Sourdaine, Bernard JégouAbstract:Concentrations of testosterone, progesterone, Delta4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17beta, 5alpha-androstane, 3alpha, 17beta-diol, and 17alpha-hydroxy, 20beta-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Delta4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn-winter for androgens and progesterone, during spring for Delta4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.
Pascal Sourdaine - One of the best experts on this subject based on the ideXlab platform.
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Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.
General and Comparative Endocrinology, 1999Co-Authors: Danielle Hélène Garnier, Pascal Sourdaine, Bernard JégouAbstract:Abstract Concentrations of testosterone, progesterone, Δ4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17β, 5α-androstane, 3α, 17β-diol, and 17α-hydroxy,20β-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Δ4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn–winter for androgens and progesterone, during spring for Δ4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.
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Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.
General and comparative endocrinology, 1999Co-Authors: Danielle Hélène Garnier, Pascal Sourdaine, Bernard JégouAbstract:Concentrations of testosterone, progesterone, Delta4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17beta, 5alpha-androstane, 3alpha, 17beta-diol, and 17alpha-hydroxy, 20beta-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Delta4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn-winter for androgens and progesterone, during spring for Delta4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.
C. J. Secombes - One of the best experts on this subject based on the ideXlab platform.
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Cloning of iNOS in the small spotted catshark (Scyliorhinus canicula).
Developmental and comparative immunology, 2001Co-Authors: Jennifer I. Reddick, Anna Goostrey, C. J. SecombesAbstract:Abstract The first cartilaginous fish iNOS gene has been cloned in the small spotted catshark, Scyliorhinus canicula . The cDNA was 4568 bp long, with a 3375 bp open reading frame encoding a protein of 1125 amino acids and a predicted molecular mass of 127.8 kDa. The catshark translation had 77% amino acid similarity with chicken iNOS and 70–73% similarity with known teleost iNOS molecules. The various co-factor binding sites were well conserved, with the calmodulin site hydrophobicity profile noticeably more similar to tetrapod molecules than teleost molecules. The catshark iNOS transcript was not typically expressed constitutively, with the exception of the gills. Clear induction of the gene was seen in splenocytes after exposure to Vibrio anguillarum in vivo, and after stimulation with LPS in vitro. iNOS message was first seen 2 h after in vitro stimulation, and was still apparent at 24 h post-stimulation, the last timing studied. Poly I:C was also able to induce iNOS transcript expression in splenocytes, albeit at a later timing (i.e.24 h). Such findings suggest a role for this molecule in the non-specific defences of cartilaginous fish as seen in other vertebrate groups.