|
Follicle-stimulating Hormone Insensitivity
Follicle-stimulating hormone (FSH) insensitivity, or ovarian insensitivity to FSH in females, also referable to as ovarian follicle hypoplasia or granulosa cell hypoplasia in females, is a rare autosomal recessive genetic and endocrine syndrome affecting both females and males, with the former presenting with much greater severity of symptomatology. It is characterized by a resistance or complete insensitivity to the effects of follicle-stimulating hormone (FSH), a gonadotropin which is normally responsible for the stimulation of estrogen production by the ovaries in females and maintenance of fertility in both sexes. The condition manifests itself as hypergonadotropic hypogonadism (decreased or lack of production of sex steroids by the gonads despite high circulating levels of gonadotropins), reduced or absent puberty (lack of development of secondary sexual characteristics, resulting in sexual infantilism if left untreated), amenorrhea (lack of menstruation), and infertility ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Recessive
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomplete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infertility
Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state of a human child or other young offspring, because they have not undergone puberty, which is the body's start of reproductive capacity. In humans, infertility is the inability to become pregnant after one year of unprotected and regular sexual intercourse involving a male and female partner.Chowdhury SH, Cozma AI, Chowdhury JH. Infertility. Essentials for the Canadian Medical Licensing Exam: Review and Prep for MCCQE Part I. 2nd edition. Wolters Kluwer. Hong Kong. 2017. There are many causes of infertility, including some that medical intervention can treat. Estimates from 1997 suggest that worldwide about five percent of all heterosexual couples have an unresolved problem with infertility. Many more couples, however, experience involu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estradiol
Estradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Estradiol is responsible for the development of female secondary sexual characteristics such as the breasts, widening of the hips and a female-associated pattern of fat distribution. It is also important in the development and maintenance of female reproductive tissues such as the mammary glands, uterus and vagina during puberty, adulthood and pregnancy. It also has important effects in many other tissues including bone, fat, skin, liver, and the brain. Though estradiol levels in males are much lower than in females, estradiol has important roles in males as well. Apart from humans and other mammals, estradiol is also found in most vertebrates and crustaceans, insects, fish, and other animal species. Estradiol is produced especially within the follicles of the ovaries, but also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androstenedione
Androstenedione, or 4-androstenedione (abbreviated as A4 or Δ4-dione), also known as androst-4-ene-3,17-dione, is an endogenous weak androgen steroid hormone and intermediate in the biosynthesis of estrone and of testosterone from dehydroepiandrosterone (DHEA). It is closely related to androstenediol (androst-5-ene-3β,17β-diol). Biological function Androstenedione is a precursor of testosterone and other androgens, as well as of estrogens like estrone, in the body. In addition to functioning as an endogenous prohormone, androstenedione also has weak androgenic activity in its own right. Androstenedione has been found to possess some estrogenic activity, similarly to other DHEA metabolites. However, in contrast to androstenediol, its affinity for the estrogen receptors is very low, with less than 0.01% of the affinity of estradiol for both the ERα and ERβ. Adrenarche In children aged 6 to 8 years old, there is a rise in androstenedione secretion along with DHEA during ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracrine Signalling
Paracrine signaling is a form of cell signaling, a type of cellular communication in which a cell produces a signal to induce changes in nearby cells, altering the behaviour of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to cell signaling by endocrine factors, hormones which travel considerably longer distances via the circulatory system; juxtacrine interactions; and autocrine signaling. Cells that produce paracrine factors secrete them into the immediate extracellular environment. Factors then travel to nearby cells in which the gradient of factor received determines the outcome. However, the exact distance that paracrine factors can travel is not certain. Although paracrine signaling elicits a diverse array of responses in the induced cells, most paracrine factors utilize a relatively streamlined set of receptors and pathways. In fact, different organs in the body - even between different sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperandrogenism
Hyperandrogenism is a medical condition characterized by high levels of androgens. It is more common in women than men. Symptoms of hyperandrogenism may include acne, seborrhea (inflamed skin), hair loss on the scalp, increased body or facial hair, and infrequent or absent menstruation. Complications may include high blood cholesterol and diabetes. It occurs in approximately 5% of women of reproductive age. Polycystic ovary syndrome accounts for about 70% of hyperandrogenism cases. Other causes include adrenal hyperplasia, hirsutism, insulin resistance, hyperprolactinemia, Cushing's disease, certain types of cancers, and certain medications. Diagnosis often involves blood tests for testosterone, 17-hydroxyprogesterone, and prolactin, as well as a pelvic ultrasound. Treatment depends on the underlying cause. Symptoms of hyperandrogenism can be treated with birth control pills or antiandrogens, such as cyproterone acetate or spironolactone. Other palliative measures may in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromatase
Aromatase (), also called estrogen synthetase or estrogen synthase, is an enzyme responsible for a key step in the biosynthesis of estrogens. It is CYP19A1, a member of the cytochrome P450 superfamily, which are monooxygenases that catalyze many reactions involved in steroidogenesis. In particular, aromatase is responsible for the aromatization of androgens into estrogens. The enzyme aromatase can be found in many tissues including gonads (granulosa cells), brain, adipose tissue, placenta, blood vessels, skin, and bone, as well as in tissue of endometriosis, uterine fibroids, breast cancer, and endometrial cancer. It is an important factor in sexual development. Function Aromatase is localized in the endoplasmic reticulum where it is regulated by tissue-specific promoters that are in turn controlled by hormones, cytokines, and other factors. It catalyzes the last steps of estrogen biosynthesis from androgens (specifically, it transforms androstenedione to estrone and testo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theca Cell
The theca folliculi comprise a layer of the ovarian follicles. They appear as the follicles become secondary follicles. The theca are divided into two layers, the theca interna and the theca externa. Theca cells are a group of endocrine cells in the ovary made up of connective tissue surrounding the follicle. They have many diverse functions, including promoting folliculogenesis and recruitment of a single follicle during ovulation. Theca cells and granulosa cells together form the stroma of the ovary. Androgen synthesis Theca cells are responsible for synthesizing androgens, providing signal transduction between granulosa cells and oocytes during development by the establishment of a vascular system, providing nutrients, and providing structure and support to the follicle as it matures. Theca cells are responsible for the production of androstenedione, and indirectly the production of 17β estradiol, also called E2, by supplying the neighboring granulosa cells with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testosterone
Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. In addition, testosterone in both sexes is involved in health and well-being, including moods, behaviour, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss. Testosterone is a steroid from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites. It exerts its action through binding to and activation of the androgen receptor. In humans and most other vertebrates, testosterone is secreted primarily by the testicles of male ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhibin B
Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. Identified in 1986, activin enhances FSH biosynthesis and secretion, and participates in the regulation of the menstrual cycle. Many other functions have been found to be exerted by activin, including roles in cell proliferation, differentiation, apoptosis, metabolism, homeostasis, immune response, wound repair, and endocrine function. Conversely, inhibin downregulates FSH synthesis and inhibits FSH secretion. The existence of inhibin was hypothesized as early as 1916; however, it was not demonstrated to exist until Neena Schwartz and Cornelia Channing's work in the mid-1970s, after which both proteins were molecularly characterized ten years later. Activin is a dimer composed of two identical or very similar beta subunits. Inhibin is also a dimer wherein the first component is a beta subunit similar or identical to the beta subunit in activin. However, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudohermaphroditism
Pseudohermaphroditism is a condition in which an individual has a matching chromosomal and gonadal tissue (ovary or testis) sex, but mismatching external genitalia. Female pseudohermaphroditism refers to an individual with ovaries and external genitalia resembling those of a male. Male pseudohermaphroditism refers to an individual with testes and external genitalia resembling those of a female. In some cases, external sex organs associated with pseudohermaphroditism appear intermediate between a typical clitoris and penis. Thus, pseudohermaphroditism is sometimes not identified until puberty or adulthood. The term contrasts with true hermaphroditism, a condition describing an individual with both female and male reproductive organs. Associated conditions include 5-α-reductase deficiency and androgen insensitivity syndrome. Mechanism Sex is determined by chromosomes during fertilization. In the early stages of human development, a human embryo has the precursors of female (p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambiguous Genitalia
Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical binary notions of male or female bodies". Sex assignment at birth usually aligns with a child's anatomical sex and phenotype. The number of births with ambiguous genitals is in the range of 1:2000–1:4500 (0.022%–0.05%). Other conditions involve atypical chromosomes, gonads, or hormones. Some persons may be assigned and raised as a girl or boy but then identify with another gender later in life, while most continue to identify with their assigned sex. The number of births where the baby is intersex has been reported differently depending on who reports and which definition of intersex is used. Anne Fausto-Sterling and her co-authors suggest that the prevalence of "nondimorphic sexual development" might be as high as 1.7%. A study publishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
