[Genes, hormones and the risk factors in the development of the male phenotype].
The onset of the expression of Sry and other sex-determining genes such as SF-1, DAX-1, WT-1 and SOX family initiates the testis organogenesis from the bipotential primordium. The fetal testis produces anti-Mullerian hormone and testosterone. These two hormones play essential role in the further development of the male phenotype. The bases for the activity of the sexual function and behavior are created within frames of these processes. Interindividual differences in these characters may achieve high degrees. Alleles of the sex-determining genes and the genes of the other genetic systems which participate in regulation of reproduction may be responsible for this variability. For example, the inherited variations in testosterone levels in the blood are negatively correlated to the alpha2-adrenergic receptor densities in the hypothalamus in males of mouse strains. Testosterone level in the fetal blood during critical period of sexual differentiation is one of the key points through which genetic and ontogenetic factors affect male sexual development. We have found nearly twofold interstrain differences in testosterone levels in the blood of male rat fetuses of 2 strains. The rats with higher testosterone levels during intrauterine development have higher rates of sexual maturation and sexual activity in future life. Genetic differences were also found in sensitivity of fetal testosterone to disruptive influences. These differences may be the reason for the strain-specific effects of prenatal stress or glucocorticoid treatment on the male sexual development in rats and mice. Substances and treatments which are capable of changing testosterone levels and/or interaction of these hormones with their receptors: ionizing radiation, pesticides, xenoestrogenes, drugs, alcohol, various stressors are the risk factors of the male sexual development.
Shishkina
G T
GT
Institute of Cytology and Genetics, Novosibirsk.
Dygalo
N N
NN
D000818:Animals; D014644:Genetic Variation / Q000502:physiology; D012739:Gonadal Steroid Hormones / Q000502:physiology*; D008297:Male; D051379:Mice; D010641:Phenotype; D051381:Rats; D012307:Risk Factors; D019849:Sex Determination Processes; D013737:Testis / Q000196:embryology / Q000502:physiology; D014998:Y Chromosome / Q000235:genetics / Q000502:physiology
D012739:Gonadal Steroid Hormones