The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Edoardo Guastamacchia - One of the best experts on this subject based on the ideXlab platform.
-
the role of long acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism
The Journal of Sexual Medicine, 2011Co-Authors: Vito Angelo Giagulli, Vincenzo Triggiani, Maria D. Carbone, Giovanni Corona, E. Tafaro, Brunella Licchelli, Edoardo GuastamacchiaAbstract:ABSTRACT Introduction Androgens are able to induce the development of Secondary Sexual Characteristics in male patients suffering from hypogonadism. So far, the most common method of administering testosterone to induce puberty in these patients has been via the injection of testosterone ester formulations. Moreover, some evidence has showed that the length of polymorphism Cytosine‐Adenine‐Guanine (CAG) trinucleotide repeats present in androgen receptor (AR) gene might co‐regulate the effectiveness of testosterone therapy. Aim The aim of this study is to evaluate the effectiveness of a long‐acting injectable testosterone undecanoate (TU) formulation for the induction of Secondary Sexual Characteristics in young males with hypogonadotropic hypogonadism (HH). Main Outcome Measures We studied the different stages of puberty development that occur progressively according to the continuous increase in serum testosterone levels and, secondly, whether these changes might be modulated by the length of CAG repeats. Methods Nine male subjects over the age of 17 that had not undergone pubertal development because of HH were enrolled in this study and compared with 15 control males. Of these patients, 6/9 suffered from idiopathic HH and 3/9 experienced hypogonadism related to β‐thalassemia (BT). All patients underwent a clinical examination and a determination of follicle‐stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), and total testosterone (T) serum levels; the free fraction (FT) and biologically active fraction of testosterone were also determined. The number of CAG triplets present in the AR gene was obtained for each patient. For treatment, HH patients received an oral TU (Andriol, 120 mg/day) for 3 months, followed by intramuscular injection of parenteral TU (Nebid, 1,000 mg) every 14 weeks for 1 year, then every 12 weeks for a second year. Serum T and SHBG levels were assayed 3 months after the start of oral TU treatment and also in the 10th week following the start of the second round of intramuscular TU injections (e.g., the eighth month). Levels were also determined 12, 18, and 24 months after the start of the parenteral TU treatments. Results Serum levels of T, SHBG, FT, and BT increased in all of the patients receiving oral TU and parental TU treatments, and this was accompanied by a development of Secondary Sexual Characteristics. For treated patients with >24 CAG triples vs. the HH subjects with ≤24 CAG triplets, a slight delay in the appearance of the most advanced phases of puberty and a slightly reduced final penis length were observed, suggesting that AR CAG polymorphism might co‐regulate the effectiveness of T treatment. Conclusions Long‐acting parental TU was able to induce the puberty in our group of HH patients, even though additional studies are needed to elucidate the possible role of CAG repeats' length for the development of Secondary Sexual Characteristics in young men with HH. Giagulli VA, Triggiani V, Carbone MD, Corona G, Tafaro E, Licchelli B, and Guastamacchia E. The role of long‐acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism. J Sex Med **;**:**–**.
-
The Role of Long‐Acting Parenteral Testosterone Undecanoate Compound in the Induction of Secondary Sexual Characteristics in Males with Hypogonadotropic Hypogonadism
The Journal of Sexual Medicine, 2011Co-Authors: Vito Angelo Giagulli, Vincenzo Triggiani, Maria D. Carbone, Giovanni Corona, E. Tafaro, Brunella Licchelli, Edoardo GuastamacchiaAbstract:ABSTRACT Introduction Androgens are able to induce the development of Secondary Sexual Characteristics in male patients suffering from hypogonadism. So far, the most common method of administering testosterone to induce puberty in these patients has been via the injection of testosterone ester formulations. Moreover, some evidence has showed that the length of polymorphism Cytosine‐Adenine‐Guanine (CAG) trinucleotide repeats present in androgen receptor (AR) gene might co‐regulate the effectiveness of testosterone therapy. Aim The aim of this study is to evaluate the effectiveness of a long‐acting injectable testosterone undecanoate (TU) formulation for the induction of Secondary Sexual Characteristics in young males with hypogonadotropic hypogonadism (HH). Main Outcome Measures We studied the different stages of puberty development that occur progressively according to the continuous increase in serum testosterone levels and, secondly, whether these changes might be modulated by the length of CAG repeats. Methods Nine male subjects over the age of 17 that had not undergone pubertal development because of HH were enrolled in this study and compared with 15 control males. Of these patients, 6/9 suffered from idiopathic HH and 3/9 experienced hypogonadism related to β‐thalassemia (BT). All patients underwent a clinical examination and a determination of follicle‐stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), and total testosterone (T) serum levels; the free fraction (FT) and biologically active fraction of testosterone were also determined. The number of CAG triplets present in the AR gene was obtained for each patient. For treatment, HH patients received an oral TU (Andriol, 120 mg/day) for 3 months, followed by intramuscular injection of parenteral TU (Nebid, 1,000 mg) every 14 weeks for 1 year, then every 12 weeks for a second year. Serum T and SHBG levels were assayed 3 months after the start of oral TU treatment and also in the 10th week following the start of the second round of intramuscular TU injections (e.g., the eighth month). Levels were also determined 12, 18, and 24 months after the start of the parenteral TU treatments. Results Serum levels of T, SHBG, FT, and BT increased in all of the patients receiving oral TU and parental TU treatments, and this was accompanied by a development of Secondary Sexual Characteristics. For treated patients with >24 CAG triples vs. the HH subjects with ≤24 CAG triplets, a slight delay in the appearance of the most advanced phases of puberty and a slightly reduced final penis length were observed, suggesting that AR CAG polymorphism might co‐regulate the effectiveness of T treatment. Conclusions Long‐acting parental TU was able to induce the puberty in our group of HH patients, even though additional studies are needed to elucidate the possible role of CAG repeats' length for the development of Secondary Sexual Characteristics in young men with HH. Giagulli VA, Triggiani V, Carbone MD, Corona G, Tafaro E, Licchelli B, and Guastamacchia E. The role of long‐acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism. J Sex Med **;**:**–**.
-
The Role of Long‐Acting Parenteral Testosterone Undecanoate Compound in the Induction of Secondary Sexual Characteristics in Males with Hypogonadotropic Hypogonadism
The Journal of Sexual Medicine, 2011Co-Authors: Vito Angelo Giagulli, Vincenzo Triggiani, Maria D. Carbone, Giovanni Corona, E. Tafaro, Brunella Licchelli, Edoardo GuastamacchiaAbstract:ABSTRACT Introduction Androgens are able to induce the development of Secondary Sexual Characteristics in male patients suffering from hypogonadism. So far, the most common method of administering testosterone to induce puberty in these patients has been via the injection of testosterone ester formulations. Moreover, some evidence has showed that the length of polymorphism Cytosine‐Adenine‐Guanine (CAG) trinucleotide repeats present in androgen receptor (AR) gene might co‐regulate the effectiveness of testosterone therapy. Aim The aim of this study is to evaluate the effectiveness of a long‐acting injectable testosterone undecanoate (TU) formulation for the induction of Secondary Sexual Characteristics in young males with hypogonadotropic hypogonadism (HH). Main Outcome Measures We studied the different stages of puberty development that occur progressively according to the continuous increase in serum testosterone levels and, secondly, whether these changes might be modulated by the length of CAG repeats. Methods Nine male subjects over the age of 17 that had not undergone pubertal development because of HH were enrolled in this study and compared with 15 control males. Of these patients, 6/9 suffered from idiopathic HH and 3/9 experienced hypogonadism related to β‐thalassemia (BT). All patients underwent a clinical examination and a determination of follicle‐stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), and total testosterone (T) serum levels; the free fraction (FT) and biologically active fraction of testosterone were also determined. The number of CAG triplets present in the AR gene was obtained for each patient. For treatment, HH patients received an oral TU (Andriol, 120 mg/day) for 3 months, followed by intramuscular injection of parenteral TU (Nebid, 1,000 mg) every 14 weeks for 1 year, then every 12 weeks for a second year. Serum T and SHBG levels were assayed 3 months after the start of oral TU treatment and also in the 10th week following the start of the second round of intramuscular TU injections (e.g., the eighth month). Levels were also determined 12, 18, and 24 months after the start of the parenteral TU treatments. Results Serum levels of T, SHBG, FT, and BT increased in all of the patients receiving oral TU and parental TU treatments, and this was accompanied by a development of Secondary Sexual Characteristics. For treated patients with >24 CAG triples vs. the HH subjects with ≤24 CAG triplets, a slight delay in the appearance of the most advanced phases of puberty and a slightly reduced final penis length were observed, suggesting that AR CAG polymorphism might co‐regulate the effectiveness of T treatment. Conclusions Long‐acting parental TU was able to induce the puberty in our group of HH patients, even though additional studies are needed to elucidate the possible role of CAG repeats' length for the development of Secondary Sexual Characteristics in young men with HH. Giagulli VA, Triggiani V, Carbone MD, Corona G, Tafaro E, Licchelli B, and Guastamacchia E. The role of long‐acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism. J Sex Med **;**:**–**.
Vito Angelo Giagulli - One of the best experts on this subject based on the ideXlab platform.
-
the role of long acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism
The Journal of Sexual Medicine, 2011Co-Authors: Vito Angelo Giagulli, Vincenzo Triggiani, Maria D. Carbone, Giovanni Corona, E. Tafaro, Brunella Licchelli, Edoardo GuastamacchiaAbstract:ABSTRACT Introduction Androgens are able to induce the development of Secondary Sexual Characteristics in male patients suffering from hypogonadism. So far, the most common method of administering testosterone to induce puberty in these patients has been via the injection of testosterone ester formulations. Moreover, some evidence has showed that the length of polymorphism Cytosine‐Adenine‐Guanine (CAG) trinucleotide repeats present in androgen receptor (AR) gene might co‐regulate the effectiveness of testosterone therapy. Aim The aim of this study is to evaluate the effectiveness of a long‐acting injectable testosterone undecanoate (TU) formulation for the induction of Secondary Sexual Characteristics in young males with hypogonadotropic hypogonadism (HH). Main Outcome Measures We studied the different stages of puberty development that occur progressively according to the continuous increase in serum testosterone levels and, secondly, whether these changes might be modulated by the length of CAG repeats. Methods Nine male subjects over the age of 17 that had not undergone pubertal development because of HH were enrolled in this study and compared with 15 control males. Of these patients, 6/9 suffered from idiopathic HH and 3/9 experienced hypogonadism related to β‐thalassemia (BT). All patients underwent a clinical examination and a determination of follicle‐stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), and total testosterone (T) serum levels; the free fraction (FT) and biologically active fraction of testosterone were also determined. The number of CAG triplets present in the AR gene was obtained for each patient. For treatment, HH patients received an oral TU (Andriol, 120 mg/day) for 3 months, followed by intramuscular injection of parenteral TU (Nebid, 1,000 mg) every 14 weeks for 1 year, then every 12 weeks for a second year. Serum T and SHBG levels were assayed 3 months after the start of oral TU treatment and also in the 10th week following the start of the second round of intramuscular TU injections (e.g., the eighth month). Levels were also determined 12, 18, and 24 months after the start of the parenteral TU treatments. Results Serum levels of T, SHBG, FT, and BT increased in all of the patients receiving oral TU and parental TU treatments, and this was accompanied by a development of Secondary Sexual Characteristics. For treated patients with >24 CAG triples vs. the HH subjects with ≤24 CAG triplets, a slight delay in the appearance of the most advanced phases of puberty and a slightly reduced final penis length were observed, suggesting that AR CAG polymorphism might co‐regulate the effectiveness of T treatment. Conclusions Long‐acting parental TU was able to induce the puberty in our group of HH patients, even though additional studies are needed to elucidate the possible role of CAG repeats' length for the development of Secondary Sexual Characteristics in young men with HH. Giagulli VA, Triggiani V, Carbone MD, Corona G, Tafaro E, Licchelli B, and Guastamacchia E. The role of long‐acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism. J Sex Med **;**:**–**.
-
The Role of Long‐Acting Parenteral Testosterone Undecanoate Compound in the Induction of Secondary Sexual Characteristics in Males with Hypogonadotropic Hypogonadism
The Journal of Sexual Medicine, 2011Co-Authors: Vito Angelo Giagulli, Vincenzo Triggiani, Maria D. Carbone, Giovanni Corona, E. Tafaro, Brunella Licchelli, Edoardo GuastamacchiaAbstract:ABSTRACT Introduction Androgens are able to induce the development of Secondary Sexual Characteristics in male patients suffering from hypogonadism. So far, the most common method of administering testosterone to induce puberty in these patients has been via the injection of testosterone ester formulations. Moreover, some evidence has showed that the length of polymorphism Cytosine‐Adenine‐Guanine (CAG) trinucleotide repeats present in androgen receptor (AR) gene might co‐regulate the effectiveness of testosterone therapy. Aim The aim of this study is to evaluate the effectiveness of a long‐acting injectable testosterone undecanoate (TU) formulation for the induction of Secondary Sexual Characteristics in young males with hypogonadotropic hypogonadism (HH). Main Outcome Measures We studied the different stages of puberty development that occur progressively according to the continuous increase in serum testosterone levels and, secondly, whether these changes might be modulated by the length of CAG repeats. Methods Nine male subjects over the age of 17 that had not undergone pubertal development because of HH were enrolled in this study and compared with 15 control males. Of these patients, 6/9 suffered from idiopathic HH and 3/9 experienced hypogonadism related to β‐thalassemia (BT). All patients underwent a clinical examination and a determination of follicle‐stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), and total testosterone (T) serum levels; the free fraction (FT) and biologically active fraction of testosterone were also determined. The number of CAG triplets present in the AR gene was obtained for each patient. For treatment, HH patients received an oral TU (Andriol, 120 mg/day) for 3 months, followed by intramuscular injection of parenteral TU (Nebid, 1,000 mg) every 14 weeks for 1 year, then every 12 weeks for a second year. Serum T and SHBG levels were assayed 3 months after the start of oral TU treatment and also in the 10th week following the start of the second round of intramuscular TU injections (e.g., the eighth month). Levels were also determined 12, 18, and 24 months after the start of the parenteral TU treatments. Results Serum levels of T, SHBG, FT, and BT increased in all of the patients receiving oral TU and parental TU treatments, and this was accompanied by a development of Secondary Sexual Characteristics. For treated patients with >24 CAG triples vs. the HH subjects with ≤24 CAG triplets, a slight delay in the appearance of the most advanced phases of puberty and a slightly reduced final penis length were observed, suggesting that AR CAG polymorphism might co‐regulate the effectiveness of T treatment. Conclusions Long‐acting parental TU was able to induce the puberty in our group of HH patients, even though additional studies are needed to elucidate the possible role of CAG repeats' length for the development of Secondary Sexual Characteristics in young men with HH. Giagulli VA, Triggiani V, Carbone MD, Corona G, Tafaro E, Licchelli B, and Guastamacchia E. The role of long‐acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism. J Sex Med **;**:**–**.
-
The Role of Long‐Acting Parenteral Testosterone Undecanoate Compound in the Induction of Secondary Sexual Characteristics in Males with Hypogonadotropic Hypogonadism
The Journal of Sexual Medicine, 2011Co-Authors: Vito Angelo Giagulli, Vincenzo Triggiani, Maria D. Carbone, Giovanni Corona, E. Tafaro, Brunella Licchelli, Edoardo GuastamacchiaAbstract:ABSTRACT Introduction Androgens are able to induce the development of Secondary Sexual Characteristics in male patients suffering from hypogonadism. So far, the most common method of administering testosterone to induce puberty in these patients has been via the injection of testosterone ester formulations. Moreover, some evidence has showed that the length of polymorphism Cytosine‐Adenine‐Guanine (CAG) trinucleotide repeats present in androgen receptor (AR) gene might co‐regulate the effectiveness of testosterone therapy. Aim The aim of this study is to evaluate the effectiveness of a long‐acting injectable testosterone undecanoate (TU) formulation for the induction of Secondary Sexual Characteristics in young males with hypogonadotropic hypogonadism (HH). Main Outcome Measures We studied the different stages of puberty development that occur progressively according to the continuous increase in serum testosterone levels and, secondly, whether these changes might be modulated by the length of CAG repeats. Methods Nine male subjects over the age of 17 that had not undergone pubertal development because of HH were enrolled in this study and compared with 15 control males. Of these patients, 6/9 suffered from idiopathic HH and 3/9 experienced hypogonadism related to β‐thalassemia (BT). All patients underwent a clinical examination and a determination of follicle‐stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), and total testosterone (T) serum levels; the free fraction (FT) and biologically active fraction of testosterone were also determined. The number of CAG triplets present in the AR gene was obtained for each patient. For treatment, HH patients received an oral TU (Andriol, 120 mg/day) for 3 months, followed by intramuscular injection of parenteral TU (Nebid, 1,000 mg) every 14 weeks for 1 year, then every 12 weeks for a second year. Serum T and SHBG levels were assayed 3 months after the start of oral TU treatment and also in the 10th week following the start of the second round of intramuscular TU injections (e.g., the eighth month). Levels were also determined 12, 18, and 24 months after the start of the parenteral TU treatments. Results Serum levels of T, SHBG, FT, and BT increased in all of the patients receiving oral TU and parental TU treatments, and this was accompanied by a development of Secondary Sexual Characteristics. For treated patients with >24 CAG triples vs. the HH subjects with ≤24 CAG triplets, a slight delay in the appearance of the most advanced phases of puberty and a slightly reduced final penis length were observed, suggesting that AR CAG polymorphism might co‐regulate the effectiveness of T treatment. Conclusions Long‐acting parental TU was able to induce the puberty in our group of HH patients, even though additional studies are needed to elucidate the possible role of CAG repeats' length for the development of Secondary Sexual Characteristics in young men with HH. Giagulli VA, Triggiani V, Carbone MD, Corona G, Tafaro E, Licchelli B, and Guastamacchia E. The role of long‐acting parenteral testosterone undecanoate compound in the induction of Secondary Sexual Characteristics in males with hypogonadotropic hypogonadism. J Sex Med **;**:**–**.
Ørjan Karlsen - One of the best experts on this subject based on the ideXlab platform.
-
The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)
Ices Journal of Marine Science, 2008Co-Authors: Jon Egil Skjæraasen, Justin J. Meager, Ørjan KarlsenAbstract:Skjaeraasen, J. E., Meager, J. J., and Karlsen, O. 2008. The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua). - ICES Journal of Marine Science, 65: 1710-1716.We examined the expression of the two known Secondary Sexual Characteristics of Atlantic cod, the pelvic fin and the drumming muscle, in farmed and wild cod stemming from the same population. Farmed and wild males had longer pelvic fins and larger drumming muscles than females, but wild cod had longer fins than farmed cod. The size of the drumming muscle of males was similar among wild and farmed cod, but farmed females had smaller muscles than their wild counterparts. Repeat-spawning wild males tended to invest less in drumming-muscle mass and more in pelvic-fin growth than recruit-spawning fish, whereas the reverse was true for farmed males. Males use pelvic fins to embrace females during ventral mounts, a key mating behaviour, and display them to other males during agonistic interactions. The drumming muscle is used by males to produce sound during courtship and aggressive displays, whereas females only use sound outside the spawning season, for agonistic and defensive behaviours that are unlikely to be as important in the farming environment. The results are discussed in the context of the reproductive success of farmed escapees in the wild.
-
The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)
Ices Journal of Marine Science, 2008Co-Authors: Jon Egil Skjæraasen, Justin J. Meager, Ørjan KarlsenAbstract:Skjaeraasen, J. E., Meager, J. J., and Karlsen, O. 2008. The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua). - ICES Journal of Marine Science, 65: 1710-1716.We examined the expression of the two known Secondary Sexual Characteristics of Atlantic cod, the pelvic fin and the drumming muscle, in farmed and wild cod stemming from the same population. Farmed and wild males had longer pelvic fins and larger drumming muscles than females, but wild cod had longer fins than farmed cod. The size of the drumming muscle of males was similar among wild and farmed cod, but farmed females had smaller muscles than their wild counterparts. Repeat-spawning wild males tended to invest less in drumming-muscle mass and more in pelvic-fin growth than recruit-spawning fish, whereas the reverse was true for farmed males. Males use pelvic fins to embrace females during ventral mounts, a key mating behaviour, and display them to other males during agonistic interactions. The drumming muscle is used by males to produce sound during courtship and aggressive displays, whereas females only use sound outside the spawning season, for agonistic and defensive behaviours that are unlikely to be as important in the farming environment. The results are discussed in the context of the reproductive success of farmed escapees in the wild.
Jon Egil Skjæraasen - One of the best experts on this subject based on the ideXlab platform.
-
Secondary Sexual Characteristics in codfishes (Gadidae) in relation to sound production, habitat use and social behaviour
Marine Biology Research, 2012Co-Authors: Jon Egil Skjæraasen, Justin J. Meager, Mikko HeinoAbstract:Abstract Little is known about the reproductive biology of the codfishes (Gadidae). Lacking direct observations, the study of Secondary Sexual Characteristics can provide cues to their reproductive biology and behaviour. We reviewed here published accounts on Sexual dimorphisms in 25 gadids in light of their general lifestyle, i.e. pelagic or demersal, and social behaviour. In addition, complementary data on fin lengths and drumming muscle size in haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), blue whiting (Micromesistius poutassou) and cod (Gadus morhua) are presented. Capacity for sound production occurred in almost half of the studied species, but was most prevalent in demersal species, where it is probably used in resource contests and to attract mates. For semi-pelagic gadids, we postulate that sound production may be linked to the formation of male-biased spawning shoals and the attraction of females towards such shoals; we identify candidate species to further test this hypothesis....
-
The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)
Ices Journal of Marine Science, 2008Co-Authors: Jon Egil Skjæraasen, Justin J. Meager, Ørjan KarlsenAbstract:Skjaeraasen, J. E., Meager, J. J., and Karlsen, O. 2008. The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua). - ICES Journal of Marine Science, 65: 1710-1716.We examined the expression of the two known Secondary Sexual Characteristics of Atlantic cod, the pelvic fin and the drumming muscle, in farmed and wild cod stemming from the same population. Farmed and wild males had longer pelvic fins and larger drumming muscles than females, but wild cod had longer fins than farmed cod. The size of the drumming muscle of males was similar among wild and farmed cod, but farmed females had smaller muscles than their wild counterparts. Repeat-spawning wild males tended to invest less in drumming-muscle mass and more in pelvic-fin growth than recruit-spawning fish, whereas the reverse was true for farmed males. Males use pelvic fins to embrace females during ventral mounts, a key mating behaviour, and display them to other males during agonistic interactions. The drumming muscle is used by males to produce sound during courtship and aggressive displays, whereas females only use sound outside the spawning season, for agonistic and defensive behaviours that are unlikely to be as important in the farming environment. The results are discussed in the context of the reproductive success of farmed escapees in the wild.
-
The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)
Ices Journal of Marine Science, 2008Co-Authors: Jon Egil Skjæraasen, Justin J. Meager, Ørjan KarlsenAbstract:Skjaeraasen, J. E., Meager, J. J., and Karlsen, O. 2008. The expression of Secondary Sexual Characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua). - ICES Journal of Marine Science, 65: 1710-1716.We examined the expression of the two known Secondary Sexual Characteristics of Atlantic cod, the pelvic fin and the drumming muscle, in farmed and wild cod stemming from the same population. Farmed and wild males had longer pelvic fins and larger drumming muscles than females, but wild cod had longer fins than farmed cod. The size of the drumming muscle of males was similar among wild and farmed cod, but farmed females had smaller muscles than their wild counterparts. Repeat-spawning wild males tended to invest less in drumming-muscle mass and more in pelvic-fin growth than recruit-spawning fish, whereas the reverse was true for farmed males. Males use pelvic fins to embrace females during ventral mounts, a key mating behaviour, and display them to other males during agonistic interactions. The drumming muscle is used by males to produce sound during courtship and aggressive displays, whereas females only use sound outside the spawning season, for agonistic and defensive behaviours that are unlikely to be as important in the farming environment. The results are discussed in the context of the reproductive success of farmed escapees in the wild.
Sharon B. Emerson - One of the best experts on this subject based on the ideXlab platform.
-
Vertebrate Secondary Sexual Characteristics-Physiological Mechanisms and Evolutionary Patterns.
The American Naturalist, 2000Co-Authors: Sharon B. EmersonAbstract:abstract: As most commonly presented, the organization‐activation theory of Sexual differentiation emphasizes the importance of the relative age of the organism for understanding steroid hormone effects. However, considering the actual physiological mechanisms of tissue enlargement (hyperplasia/hypertrophy) provides an additional perspective for interpreting patterns of evolutionary change in Sexual dimorphism. Using that focus, it is possible to suggest mechanistic explanations for patterns of allometry and the size of some Secondary Sexual Characteristics produced by “runaway” selection. It can also lead to the formulation of testable hypotheses regarding the type of Sexually dimorphic characters that might evolve through “good genes” models; the relationship between intraSexual competition, polygyny, and the development and size of male weapons; and the control and type of Secondary Sexual Characteristics that will be present in males with associated and disassociated reproductive patterns.
-
Male Secondary Sexual Characteristics, Sexual selection, and molecular divergence in fanged ranid frogs of Southeast Asia
Zoological Journal of the Linnean Society, 1998Co-Authors: Sharon B. Emerson, Ryk WardAbstract:Abstract A group of Southeast Asian frogs of the family Ranidae are characterized by a suite of unusual Secondary Sexual Characteristics. Males are larger than females, possess bony odontoid processes (fangs) and have enlarged heads. While all members of this clade are Sexually dimorphic in this suite of characters, the degree of development of the Secondary Sexual Characteristics in males varies widely across species. One of the most common species, Rana blythii Boulenger, has an extremely broad geographical range. This frog lacks an advertisement call in Borneo but calling has been reported in populations from peninsular Malaysia and Vietnam. This study examines the relationship between the expression of male Secondary Sexual Characteristics, molecular divergence and number of speciation events in widely separated populations of R. blythii , and between R. blythii and other species of closely related fanged frogs belonging to the grunniens species group. Results from morphometric and sequence data indicate that (1) there is no correlation between morphological and molecular distance in these frogs and (2) there is no correlation between morphological distance and the number of speciation events separating taxa. Systematic analysis demonstrates that R. blythii , as currently recognized, is not a single species nor is it monophyletic.
-
Hormonal induction of thumb pads and the evolution of Secondary Sexual Characteristics of the Southeast Asian fanged frog, Rana blythii
Journal of Experimental Zoology, 1997Co-Authors: Sharon B. Emerson, Lara S. Carroll, David L. HessAbstract:The fanged frogs of Southeast Asia do not express most of the hormone-dependent Secondary Sexual Characteristics such as thumb pads that are common to other ranid frogs. At the same point in the evolutionary history of the group that these androgen-mediated Characteristics are lost, male parental care first evolves. This behavior is often correlated with low androgen levels. Prior work indicates that in one of the fanged frogs, Rana blythii, adult males have low androgen levels compared to North Temperate species of Rana. This leads to the question of whether these low androgen levels are related to the unusual male parental care and the lack of expression of the thumb pad and other hormone-dependent Secondary Sexual Characteristics in this species. We tested that hypothesis by examining the effects of exogenous dihydrotestosterone supplements on the expression of thumb pads in Rana blythii. Dihydrotestosterone injections appear to stimulate the expression of the thumb pad in R. blythii. These results support the hypothesis that low androgen levels are involved in the loss of the thumb pad in R. blythii. This work provides an example of how mapping characters on phylogenies can be a powerful approach for gaining insights into proximate physiological mechanisms of selection at the evolutionary level. J. Exp. Zool. 279:587–596, 1997. © 1997 Wiley-Liss, Inc.
-
Phylogenies and Physiological Processes—The Evolution of Sexual Dimorphism in Southeast Asian Frogs
Systematic Biology, 1996Co-Authors: Sharon B. EmersonAbstract:There are a number of species of Southeast Asian Rana that are characterized by an unusual suite of Sexually dimorphic features and derived reproductive modes. These frogs lack the usual Secondary Sexual Characteristics of ranid frogs: nuptial pads, vocal sacs, and enlarged flexor muscles. Secondary Sexual Characteristics in frogs are under androgenic control. Phyloge- netic analyses using morphological and molecular data indicate that a drop in androgen level and/or a shift in androgen sensitivity may have been involved in the evolution of male parental care and the loss of the common suite of Secondary Sexual Characteristics in these Asian frogs. Phylogenetic analyses also provide important information on experimental design by indicating the most appropriate taxa to use in the exploration of physiological processes controlling the expression of Sexual dimorphism. This work is an example of how emergent properties from phylogenetic analyses can be used to formulate and test hypotheses of process and pattern of evolutionary change. (Frog; Rana; hormone; Sexual dimorphism; parental care.)
-
TESTING PATTERN PREDICTIONS OF Sexual SELECTION: A FROG EXAMPLE
The American Naturalist, 1994Co-Authors: Sharon B. EmersonAbstract:Some Southeast Asian species of the genus Rana possess an unusual suite of Secondary Sexual Characteristics: fangs, hypertrophied jaw muscles, enlarged heads, and males larger than females. Phylogenetic analysis indicates that these frogs form a monophyletic group. Historical transformation analysis and comparative performance tests suggest that this functional complex evolved as a result of Sexual selection. Patterns of dimorphism within the clade were used to test a series of predictions from the Sexual selection literature. As predicted, closely related species differed most in their Secondary Sexual Characteristics and Sexual selection is likely to produce novelties. Contrary to predictions, more derived taxa did not show a greater degree of Sexual dimorphism, Sexual dimorphism did not increase with body size, and the evolution of new Secondary Sexual Characteristics did not precede and therefore contribute to the loss of old Characteristics.