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331 results on '"Hammond, Geoffrey P."'

9. Development of the external genitalia: perspectives from the spotted hyena (Crocuta crocuta).

Author

Barcellos, Dale, Agarwal, Sanjana, Bhargava, Argun, Drea, Christine, Hammond, Geoffrey, Siiteri, Penti, Coscia, Elizabeth, McPhaul, Michael, Baskin, Laurence, Glickman, Stephen, Risbridger, Gail, Wang, Hong, Place, Ned, Grumbach, Mel, Cunha, Tristan, Weldele, Mary, Cunha, Gerald, and Conley, Alan

Subjects
Androgens, Clitoris, Estrogens, Hyena, Penis, Urogenital sinus, Androgens, Animals, Clitoris, Estrogens, Female, Genitalia, Female, Hyaenidae, Male, Ovary, Penis, Testis
Abstract

This review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. The female spotted hyena is the only extant mammal that mates and gives birth through a pendulous penis-like clitoris. Our studies indicate that early formation of the phallus in both males and females is independent of androgens; indeed the phallus forms before the fetal testes or ovaries are capable of synthesizing androgens. Likewise, pre- and postnatal growth in length of the penis and clitoris is minimally affected by androgen status. Nonetheless, several internal morphologies, as well as external surface features of the phallus, are androgen-dependent and thus account for dimorphism between the penis and clitoris. Finally, estrogens play a critical role in penile and clitoral development, specifying the position of the urethral orifice, determining elasticity of the urethral meatus, and facilitating epithelial-epithelial fusion events required for proper formation of the distal urethra/urogenital sinus and prepuce. Accordingly, prenatal inhibition of estrogen synthesis via administration of letrozole (an aromatase inhibitor) leads to malformations of the glans as well as the prepuce (hypospadias). The effects of prenatal androgens, anti-androgens and impaired estrogen synthesis correlated with the tissue expression of androgen and estrogen receptors.

Published
2014

10. Development of the external genitalia: perspectives from the spotted hyena (Crocuta crocuta).

Author

Cunha, Gerald R, Risbridger, Gail, Wang, Hong, Place, Ned J, Grumbach, Mel, Cunha, Tristan J, Weldele, Mary, Conley, Al J, Barcellos, Dale, Agarwal, Sanjana, Bhargava, Argun, Drea, Christine, Hammond, Geoffrey L, Siiteri, Penti, Coscia, Elizabeth M, McPhaul, Michael J, Baskin, Laurence S, and Glickman, Stephen E

Subjects
Genitalia, Female, Ovary, Clitoris, Penis, Testis, Animals, Hyaenidae, Androgens, Estrogens, Female, Male, Hyena, Urogenital sinus, Developmental Biology, Biochemistry and Cell Biology, Paediatrics and Reproductive Medicine
Abstract

This review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. The female spotted hyena is the only extant mammal that mates and gives birth through a pendulous penis-like clitoris. Our studies indicate that early formation of the phallus in both males and females is independent of androgens; indeed the phallus forms before the fetal testes or ovaries are capable of synthesizing androgens. Likewise, pre- and postnatal growth in length of the penis and clitoris is minimally affected by "androgen status". Nonetheless, several internal morphologies, as well as external surface features of the phallus, are androgen-dependent and thus account for dimorphism between the penis and clitoris. Finally, estrogens play a critical role in penile and clitoral development, specifying the position of the urethral orifice, determining elasticity of the urethral meatus, and facilitating epithelial-epithelial fusion events required for proper formation of the distal urethra/urogenital sinus and prepuce. Accordingly, prenatal inhibition of estrogen synthesis via administration of letrozole (an aromatase inhibitor) leads to malformations of the glans as well as the prepuce (hypospadias). The effects of prenatal androgens, anti-androgens and impaired estrogen synthesis correlated with the tissue expression of androgen and estrogen receptors.

Published
2014

19. Genetic determinants of serum testosterone concentrations in men.

Author

Ohlsson, Claes, Wallaschofski, Henri, Lunetta, Kathryn L, Stolk, Lisette, Perry, John RB, Koster, Annemarie, Petersen, Ann-Kristin, Eriksson, Joel, Lehtimäki, Terho, Huhtaniemi, Ilpo T, Hammond, Geoffrey L, Maggio, Marcello, Coviello, Andrea D, EMAS Study Group, Ferrucci, Luigi, Heier, Margit, Hofman, Albert, Holliday, Kate L, Jansson, John-Olov, Kähönen, Mika, Karasik, David, Karlsson, Magnus K, Kiel, Douglas P, Liu, Yongmei, Ljunggren, Osten, Lorentzon, Mattias, Lyytikäinen, Leo-Pekka, Meitinger, Thomas, Mellström, Dan, Melzer, David, Miljkovic, Iva, Nauck, Matthias, Nilsson, Maria, Penninx, Brenda, Pye, Stephen R, Vasan, Ramachandran S, Reincke, Martin, Rivadeneira, Fernando, Tajar, Abdelouahid, Teumer, Alexander, Uitterlinden, André G, Ulloor, Jagadish, Viikari, Jorma, Völker, Uwe, Völzke, Henry, Wichmann, H Erich, Wu, Tsung-Sheng, Zhuang, Wei Vivian, Ziv, Elad, Wu, Frederick CW, Raitakari, Olli, Eriksson, Anna, Bidlingmaier, Martin, Harris, Tamara B, Murray, Anna, de Jong, Frank H, Murabito, Joanne M, Bhasin, Shalender, Vandenput, Liesbeth, and Haring, Robin

Subjects
EMAS Study Group, Chromosomes, Human, X, Humans, Testosterone, Sex Hormone-Binding Globulin, Nuclear Proteins, Body Mass Index, Polymorphism, Single Nucleotide, Alleles, Adult, Aged, 80 and over, Middle Aged, Male, Genome-Wide Association Study, Aged, and over, Chromosomes, Human, X, Polymorphism, Single Nucleotide, Genetics, Developmental Biology
Abstract

Testosterone concentrations in men are associated with cardiovascular morbidity, osteoporosis, and mortality and are affected by age, smoking, and obesity. Because of serum testosterone's high heritability, we performed a meta-analysis of genome-wide association data in 8,938 men from seven cohorts and followed up the genome-wide significant findings in one in silico (n = 871) and two de novo replication cohorts (n = 4,620) to identify genetic loci significantly associated with serum testosterone concentration in men. All these loci were also associated with low serum testosterone concentration defined as

Published
2011

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