Development of urogenital system in the Spix cavy: A model for studies on sexual differentiation

2018 ◽  
Vol 101 ◽  
pp. 25-38 ◽  
Author(s):  
Amilton Cesar dos Santos ◽  
Alan James Conley ◽  
Moacir Franco de Oliveira ◽  
Antônio Chaves de Assis Neto
Keyword(s):  
Sexual Differentiation ◽  
Urogenital System

scholarly journals Gonad Grafts in Embryonic Chicks and Their Relation to Sexual Differentiation

1925 ◽  
Vol 2 (2) ◽  
pp. 165-188
Author(s):  
A. W. GREENWOOD
Keyword(s):  
Sexual Differentiation ◽  
Physiological Activity ◽  
Histological Structure ◽  
Urogenital System ◽  
Microscopical Examination ◽  
Plumage Colour ◽  
Typical Structure ◽  
Opposite Sex ◽  
Wolffian Body ◽  
Embryo Chick

1. An experimental study on the effects of gonad grafts in the embryo chick was undertaken in an attempt to reproduce the results obtained by Minoura and to define the bearing of this experiment on Lillie's theory of the free-martin in cattle. 2. Eggs from a sex-linked cross were used so as to be able to identify the original sex of the embryos. 3. In the majority of cases the egg received the graft at the seventh day of incubation and was examined at the seventeenth day, at which stage the progress of sexual differentiation is almost as complete as at the time of hatching. 4. In all 540 embryos were operated on. Of this number 233 received testis grafts and 168 ovary grafts. Other tissues grafted were thyroid, adrenal, pancreas, spleen, gall-bladder, liver, Wolffian body, kidney, lung, lens, and heart. 5. The age of the grafted tissue varied from the fourteenth day of incubation up to ten weeks old. 6. Of the gonad grafts, 150 survived the operation, 71 ♂ and 79 ♀. 47 ♀ chicks were obtained after testis grafts, and 27 ♂ chicks were obtained after ovary grafts. Healthy active testis grafts were found in 20 ♀ and 5 ovary grafts in ♂. 7. The sex ratio in the surviving chicks showed no deviation from the normal. 8. Macroscopical examination of the urogenital system showed no deviation from the typical structure consonant with the sex of the chick as determined by its plumage colour. 9. Microscopical examination of the gonads revealed no abnormalities in histological structure. 10. These results lend no confirmation to the view that the process of sexual differentiation in the chick can be profoundly modified by the specific physiological activity of a gonad graft of the opposite sex. 11. Minoura's interpretation of his results are criticised. 12. The grafting of gonad tissue in the embryo chick does not reproduce experimentally the conditions existing in the bovine free-martin in that in the former the embryo is exposed to the specific action of the grafted gonad alone, whereas in the latter the female co-twin is exposed to the action of all the internal secretions from the male.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

Iron Metabolism in the Human Body and Setting its Hygienic Limits for Drinking Water. Review. Part 2

2020 ◽  
Vol 99 (5) ◽  
pp. 504-508
Author(s):  
Natalija A. Egorova ◽  
N. V. Kanatnikova
Keyword(s):  
Oxidative Stress ◽  
Drinking Water ◽  
Iron Overload ◽  
Iron Metabolism ◽  
Subcutaneous Tissue ◽  
Allergic Diseases ◽  
The Body ◽  
Urogenital System ◽  
High Iron Content ◽  
Labile Iron Pool

Iron is an assential element for the growth, division, differentiation and functioning of any cell in the body. Iron is virtually important for human and danger at the same time, because with excessive accumulation it causes oxidative stress with formation of highly active oxygen radicals and reactive form of nitrogen that can destroy cell membranes, proteins, nucleic acids, reduce cell viability, with, according to modern concepts, can contribute to the development of many diseases (cardiovascular, rheumatic, gastrointestinal, neurodegenerative, oncological, metabolic and others), and also accelerate the aging process. Part 1 of this review discussed the issues of iron metabolism in human, including its regulation at the cellular and systemic levels, the intake, transport, use, accumulation and export of iron in cells, the role of the labile iron pool in the cytoplasm of cells and plasma non-transferrin bound iron. Data are provided on the causes, frequency and significance of iron overload in the formation of free radicals and the development of oxidative stress. Part 2 of the review provides information on diseases associated with iron overload as well as information on ferroptosis - a new type of iron-dependent regulated cell death. Attention is paid to the works of domestic authors, where it was found that prolonged use of drinking water with a high iron content is unfavorable for the population and leads to an increase in the overall incidence, the development of the diseases of the blood, skin and subcutaneous tissue, musculoskeletal system, digestive system, urogenital system, and allergic diseases. Separate publications are cited on the possibility of a negative effect of iron at concentrations in water of 0.3 mg/l and lower. The material of the review emphasizes the preventive significance of caution attitude to regulating iron in the water in the Russian Federation, where 1/3 of the population uses iron-containing water for drinking, and substantiate the feasibility of establishing a hygienic limit for iron in water not higher than 0.3 mg/l.

Involvement of preoptic estrogen receptive GABAergic neurons in the process of sexual differentiation

1984 ◽  
Vol 104 (4_Supplb) ◽  
pp. S39-S40 ◽  
Author(s):  
G. FLÜGGE ◽  
E. FUCHS ◽  
W. WUTTKE
Keyword(s):  
Sexual Differentiation ◽  
Gabaergic Neurons
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