scholarly journals The Role of Steroid Hormones in the Adjustment of Primary Sex Ratio in Birds: Compiling the Pieces of the Puzzle

2013 ◽  
Vol 53 (6) ◽  
pp. 923-937 ◽  
Author(s):  
K. J. Navara
Keyword(s):  
Sex Ratio ◽  
Steroid Hormones ◽  
Primary Sex Ratio

scholarly journals Impact of sex in the prevalence and progression of glioblastomas: the role of gonadal steroid hormones

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Claudia Bello-Alvarez ◽  
Ignacio Camacho-Arroyo
Keyword(s):  
Cell Proliferation ◽  
Steroid Hormones ◽  
Physiological State ◽  
Migration And Invasion ◽  
Low Grade ◽  
Main Body ◽  
Protective Effects ◽  
Gonadal Steroid Hormones ◽  
Gonadal Steroid

Abstract Background As in other types of cancers, sex is an essential factor in the origin and progression of glioblastomas. Research in the field of endocrinology and cancer suggests that gonadal steroid hormones play an important role in the progression and prevalence of glioblastomas. In the present review, we aim to discuss the actions and mechanism triggered by gonadal steroid hormones in glioblastomas. Main body Glioblastoma is the most common malignant primary brain tumor. According to the epidemiological data, glioblastomas are more frequent in men than in women in a 1.6/1 proportion both in children and adults. This evidence, and the knowledge about sex influence over the prevalence of countless diseases, suggest that male gonadal steroid hormones, such as testosterone, promote glioblastomas growth. In contrast, a protective role of female gonadal steroid hormones (estradiol and progesterone) against glioblastomas has been questioned. Several pieces of evidence demonstrate a variety of effects induced by female and male gonadal steroid hormones in glioblastomas. Several studies indicate that pregnancy, a physiological state with the highest progesterone and estradiol levels, accelerates the progression of low-grade astrocytomas to glioblastomas and increases the symptoms associated with these tumors. In vitro studies have demonstrated that progesterone has a dual role in glioblastoma cells: physiological concentrations promote cell proliferation, migration, and invasion while very high doses (out physiological range) reduce cell proliferation and increases cell death. Conclusion Gonadal steroid hormones can stimulate the progression of glioblastomas through the increase in proliferation, migration, and invasion. However, the effects mentioned above depend on the concentrations of these hormones and the receptor involved in hormone actions. Estradiol and progesterone can exert promoter or protective effects while the role of testosterone has been always associated to glioblastomas progression.

scholarly journals Protein Synthesis in Human Leukocytes and Lymphocytes: 1. Effect of Steroids and Sterols

Blood ◽  
1969 ◽  
Vol 34 (3) ◽  
pp. 348-356 ◽  
Author(s):  
SEYMOUR WERTHAMER ◽  
CARL HICKS ◽  
LEONARD AMARAL
Keyword(s):  
Protein Synthesis ◽  
Steroid Hormones ◽  
Plasma Protein ◽  
Human Lymphocytes ◽  
Amino Acid Incorporation ◽  
Binding Factor ◽  
In Vitro Effects ◽  
Physiologic Role

Abstract The in vitro effects of sterols, cholesterol and 3-methyl cholanthrene and steroids, cortisol, prednisolone and testosterone on protein synthesis in separate popultions of human lymphocytes and leukocytes has been investigated. It has been shown that all agents used result in the inhibition of protein synthesis under these conditions. It has also been shown that the inhibitory mechanism of the steroid hormones requires the presence of plasma, presumably as a protein binding factor in order to achieve its effect. The sterol, cholesterol and 3-methyl cholanthrene, in the absence of plasma, still inhibit amino acid incorporation. However, in the case of cholesterol, the magnitude of inhibition is lower than that observed in the presence of plasma, perhaps indicating a partial plasma dependence. The results presented therefore support the hypothesis that the inhibition of lymphocyte protein synthesis by steroid hormones occurs only when the steroid is bound to a plasma protein. The physiologic role of the plasma protein-cortisol complex and its relation to the condition of lymphopenia in man is discussed.

scholarly journals The role of steroid hormones in breast cancer stem cells

2015 ◽  
Vol 22 (6) ◽  
pp. T177-T186 ◽  
Author(s):  
Bruno M Simões ◽  
Denis G Alferez ◽  
Sacha J Howell ◽  
Robert B Clarke
Keyword(s):  
Breast Cancer ◽  
Stem Cells ◽  
Cancer Stem Cells ◽  
Steroid Hormones ◽  
Normal Mammary Gland ◽  
Breast Cancer Stem Cells ◽  
Tumor Initiating Cells ◽  
Unit Of Selection ◽  
Selection For

Breast cancer stem cells (BCSCs) are potent tumor-initiating cells in breast cancer, the most common cancer among women. BCSCs have been suggested to play a key role in tumor initiation which can lead to disease progression and formation of metastases. Moreover, BCSCs are thought to be the unit of selection for therapy-resistant clones since they survive conventional treatments, such as chemotherapy, irradiation, and hormonal therapy. The importance of the role of hormones for both normal mammary gland and breast cancer development is well established, but it was not until recently that the effects of hormones on BCSCs have been investigated. This review will discuss recent studies highlighting how ovarian steroid hormones estrogen and progesterone, as well as therapies against them, can regulate BCSC activity.

The Life-History of Badumna-Candida (Araneae, Amaurobioidea)

1993 ◽  
Vol 41 (5) ◽  
pp. 441 ◽  
Author(s):  
MF Downes
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Production Cycle ◽  
Social Spider ◽  
Social Spiders ◽  
Primary Sex Ratio ◽  
The Social ◽  
The Status ◽  
History Of ◽  
Changes Over Time

A two-year study of the social spider Badumna candida at Townsville, Queensland, provided information on colony size and changes over time, maturation synchrony, temperature effects on development, sex ratio, dispersal, colony foundation, fecundity and oviposition. Key findings were that B. candida outbred, had an iteroparous egg-production cycle between March and October, had an even primary sex ratio and achieved maturation synchrony by retarding the development of males, which matured faster than females at constant temperature. There was no overlap of generations, the cohort of young from a nest founded by a solitary female in summer dispersing the following summer as subadults (females) or subadults and adults (males). These findings confirm the status of B. candida as a periodic-social spider (an annual outbreeder), in contrast to the few known permanent-social spider species whose generations overlap. Cannibalism, normally rare in social spiders, rose to 48% when spiders were reared at a high temperature. This may be evidence that volatile recognition pheromones suppress predatory instincts in social spiders.

Behavioral Endocrinology: Integrating Mind and Body

2020 ◽  
Vol 4 (2) ◽  
pp. 97-110
Author(s):  
Peter T. Ellison
Keyword(s):  
Nervous System ◽  
Steroid Hormones ◽  
Behavioral Ecology ◽  
Endocrine System ◽  
Behavioral Endocrinology ◽  
Paternal Behavior ◽  
Mind And Body ◽  
The Central Nervous System ◽  
Primary Focus

Abstract The nervous system and the endocrine system interact to integrate behavior and physiology. Hormones play an important role in this interaction, particularly steroid hormones. Other molecules, notably oxytocin, can serve both as hormones in the soma and neuromodulators in the central nervous system. Understanding the influence of the endocrine system on human behavior, both individual and social, has been a primary focus of behavioral endocrinology for many decades, though technical and methodological challenges have been formidable. The recent enthusiasm for enzyme-linked immunoassay kits for measuring steroid hormones in saliva has been found to be largely unsound, for example. Despite these difficulties, advances in many areas have been made and new areas, such as the endocrinology of paternal behavior and the role of oxytocin in social interactions, have emerged. Reproductive ecology provides a theoretical framework for integrating the diverse content of human behavioral ecology.

scholarly journals Primary sex ratio adjustment to experimentally reduced male UV attractiveness in blue tits

2006 ◽  
Vol 17 (4) ◽  
pp. 539-546 ◽  
Author(s):  
Peter Korsten ◽  
C. (Kate) M. Lessells ◽  
A. Christa Mateman ◽  
Marco van der Velde ◽  
Jan Komdeur
Keyword(s):  
Sex Ratio ◽  
Primary Sex Ratio ◽  
Sex Ratio Adjustment ◽  
Blue Tits
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