Search results for "Androstenedione"
showing 10 items of 30 documents
Evolution of yolk androgens in birds: development, coloniality and sexual dichromatism
2007
18 pages; International audience; Current theory recognizes the adaptive value of maternal effects in shaping offspring phenotypes in response to selective pressures and vindicates the value of these traits in fostering adaptation and speciation. Yolk androgens in birds are a relatively well-known maternal effect and have been linked to adaptations related to development, coloniality life, and sexual selection. We tested whether interspecific patterns of yolk androgen levels (androstenedione and testosterone) were related to interspecific variation in development, sexual selection, and coloniality. First, we found no relationship between androgen levels and duration of development as reflec…
A Dehydrogenase Dual Hydrogen Abstraction Mechanism Promotes Estrogen Biosynthesis: Can We Expand the Functional Annotation of the Aromatase Enzyme?
2018
Cytochrome P450 (CYP450) enzymes are involved in the metabolism of exogenous compounds and in the synthesis of signaling molecules. Among the latter, human aromatase (HA) promotes estrogen biosynthesis, which is a key pharmacological target against breast cancers. After decades of debate, interest in gaining a comprehensive picture of HA catalysis has been renewed by the recent discovery that compound I (Cpd I) is the reactive species of the peculiar aromatization step. Herein, for the first time, a complete atomic-level picture of all controversial steps of estrogen biosynthesis is presented. By performing cumulative quantum-classical molecular dynamics and metadynamics simulations of abou…
Increased anti-Mullerian hormone levels and ovarian size in a subgroup of women with functional hypothalamic amenorrhea: further identification of th…
2016
Functional hypothalamic amenorrhea is a disorder characterized by cessation of menstrual cycles in the absence of organic disease. In most patients, it occurs in adult life after a stressful event and may be related to a condition of mild chronic energy deprivation. The endocrine pattern is characterized by low estrogen levels with an absent response to a progestogen challenge test and low-normal gonadotropin levels. A few studies have shown that some of these women may have some features of polycystic ovary syndrome; these features include an increased androgen response to gonadotropins, increased anti-Mullerian hormone levels, and altered ovarian morphology or increased ovarian size. Thes…
Pituitary-adrenal responses to corticotropin-releasing factor in late onset 21-hydroxylase deficiency
1990
Intravenous corticotropin-releasing factor (CRF) and adrenocorticotropin hormone (ACTH) were administered in patients with adult onset 21-hydroxylase deficiency to compare their diagnostic capability as well as to investigate hypothalamic-pituitary-adrenal function in this disorder. Responses of 17-hydroxyprogesterone, which were markedly elevated compared with controls, were identical with CRF and ACTH. However, intravenous ACTH resulted in higher androstenedione levels in comparison to CRF. Adrenocorticotropin hormone also resulted in decreased cortisol responses, confirming a defect in steroidogenesis, a finding that was not evident with CRF. Plasma ACTH responses to CRF were similar in …
Ovine corticotropin-releasing factor and dexamethasone responses in hyperandrogenic women
1990
Eighteen hyperandrogenic, hirsute women received ovine corticotropin-releasing factor (CRF; 1 microgram/kg) as well as a dexamethasone (DEX) suppression test. Nine of the 18 hirsute women exhibited increased DEX sensitivity. Plasma adrenocorticotropic hormone (ACTH) responses after ovine CRF were significantly lower in the DEX-sensitive subgroup, but serum androstenedione was higher. Baseline serum androgen levels could not predict DEX responses. A significant negative correlation existed between the suppression of androgens after DEX and the increase in ACTH after ovine CRF. The suppression of androgen correlated with the ratio of the increase in androgen to the increase in ACTH after ovin…
Alterations in androgen conjugate levels in women and men with alopecia.
1994
Objective To assess levels of androgen metabolites thought to reflect, at least in part, peripheral androgen activity in women with androgenic alopecia and men with premature balding in an effort to determine if a common abnormality exists. Design Prospective study in various groups of women and men. Setting Reproductive Endocrine Clinic at our university medical center. Patients Ten normal ovulatory female controls and 50 hyperandrogenic women divided on the basis of hirsutism and alopecia as follows: [1] 8 hirsute women with androgenic alopecia; [2] 12 nonhirsute women with androgenic alopecia; [3] 18 hirsute women without androgenic alopecia; and [4] 12 nonhirsute women without androgeni…
Acute responses of comprehensive gonadosteroids and corticosteroids to resistance exercise before and after 10 weeks of supervised strength training
2019
New Findings: What is the central question of this study? Although acute responses of the principal gonadosteroid and corticosteroid hormones to resistance exercise are well documented, there is no information regarding how the key lower-concentration intermediary hormones respond and potentially influence these hormonal pathways. What is the main finding and its importance? This study provides evidence for cascading conversions of some gonadosteroids, and the data suggest that the testosterone concentration increases independently of these hormones. These findings challenge future studies to determine the exact physiological roles of the lower-concentration gonadosteroids and corticosteroi…
Responses of serum androgenic-anabolic and catabolic hormones to prolonged strength training.
1988
Endocrine and neuromuscular effects of prolonged strength training were investigated in 21 strength-trained male subjects during the course of a 24-week progressive strength training and during a subsequent detraining period of 12 weeks. Maximal isometric leg extensor force increased by 19% (P less than 0.001) during the first 20 weeks, followed by a plateau during the 4 latest weeks of training. During the course of the training period, no systematic change was found in serum testosterone concentrations, but there was a decreasing tendency in the concentrations of free testosterone (NS), 17-OH-progesterone (NS), androstenedione (P less than 0.05), dehydroepiandrosterone (P less than 0.05),…
Pituitary-adrenal responses to ovine corticotropin-releasing factor in polycystic ovary syndrome and in other hyperandrogenic patients.
1990
This study was carried out to further characterize the pituitary-adrenal androgen responses of hyperandrogenic patients with 'classic' polycystic ovary syndrome (PCO) and others who were less distinctive and have been called 'PCO-like'. PCO-like patients differed from PCO only in that serum luteinizing hormone (LH) levels were normal and anovulation was not consistent. Ovine corticotropin-releasing factor (CRF) resulted in normal responses of adrenocorticotropic hormone and cortisol in the two groups when compared to controls, while androstenedione (delta 4A) and dehydroepiandrosterone (DHEA) responses were significantly elevated. There were no differences in the responses of PCO and PCO-li…
Reassessment of adrenal androgen secretion in women with polycystic ovary syndrome
1995
Objective To reevaluate the clinical significance of elevations of adrenal androgens in polycystic ovary syndrome (PCOS). Methods Thirty women with PCOS and ten ovulatory controls were evaluated. Serum dehydroepiandrosterone (DHEA) sulfate and 11β-hydroxyandrostenedione were measured before and after 3 and 6 months of GnRH agonist (GnRH-A) therapy. All controls and 15 women with PCOS received intravenous ACTH before and after GnRH-A therapy. Results Twenty-one (70%) of the women with PCOS had elevations of DHEA sulfate, and 16 (53%) had elevations in 11/3-hydroxyandrostenedione. Only two women with PCOS had normal values of both adrenal androgens. After GnRH-A therapy, only 11 subjects (37%…