Related Research Articles
Amenorrhea or amenorrhoea is the absence of a menstrual period in a female who has reached reproductive age. Physiological states of amenorrhoea are seen, most commonly, during pregnancy and lactation (breastfeeding). Outside the reproductive years, there is absence of menses during childhood and after menopause.
Luteinizing hormone is a hormone produced by gonadotropic cells in the anterior pituitary gland. The production of LH is regulated by gonadotropin-releasing hormone (GnRH) from the hypothalamus. In females, an acute rise of LH known as an LH surge, triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell–stimulating hormone (ICSH), it stimulates Leydig cell production of testosterone. It acts synergistically with follicle-stimulating hormone (FSH).
Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormonal signs that puberty has begun. In the United States, girls are considered to have delayed puberty if they lack breast development by age 13 or have not started menstruating by age 15. Boys are considered to have delayed puberty if they lack enlargement of the testicles by age 14. Delayed puberty affects about 2% of adolescents.
Hypogonadism means diminished functional activity of the gonads—the testicles or the ovaries—that may result in diminished production of sex hormones. Low androgen levels are referred to as hypoandrogenism and low estrogen as hypoestrogenism. These are responsible for the observed signs and symptoms in both males and females.
Gonadarche refers to the earliest gonadal changes of puberty. In response to pituitary gonadotropins, the ovaries in females and the testes in males begin to grow and increase the production of the sex steroids, especially estradiol and testosterone. The ovary and testis have receptors, follicle cells and leydig cells, respectively, where gonadotropins bind to stimulate the maturation of the gonads and secretion of estrogen and testosterone. Certain disorders can result in changes to timing or nature of these processes.
Kallmann syndrome (KS) is a genetic disorder that prevents a person from starting or fully completing puberty. Kallmann syndrome is a form of a group of conditions termed hypogonadotropic hypogonadism. To distinguish it from other forms of hypogonadotropic hypogonadism, Kallmann syndrome has the additional symptom of a total lack of sense of smell (anosmia) or a reduced sense of smell. If left untreated, people will have poorly defined secondary sexual characteristics, show signs of hypogonadism, almost invariably are infertile and are at increased risk of developing osteoporosis. A range of other physical symptoms affecting the face, hands and skeletal system can also occur.
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
The hypothalamic–pituitary–gonadal axis refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity. Because these glands often act in concert, physiologists and endocrinologists find it convenient and descriptive to speak of them as a single system.
Gonadal dysgenesis is classified as any congenital developmental disorder of the reproductive system characterized by a progressive loss of primordial germ cells on the developing gonads of an embryo. One type of gonadal dysgenesis is the development of functionless, fibrous tissue, termed streak gonads, instead of reproductive tissue. Streak gonads are a form of aplasia, resulting in hormonal failure that manifests as sexual infantism and infertility, with no initiation of puberty and secondary sex characteristics.
Estrogen insensitivity syndrome (EIS), or estrogen resistance, is a form of congenital estrogen deficiency or hypoestrogenism which is caused by a defective estrogen receptor (ER) – specifically, the estrogen receptor alpha (ERα) – that results in an inability of estrogen to mediate its biological effects in the body. Congenital estrogen deficiency can alternatively be caused by a defect in aromatase, the enzyme responsible for the biosynthesis of estrogens, a condition which is referred to as aromatase deficiency and is similar in symptomatology to EIS.
Hypergonadism is a condition where there is a hyperfunction of the gonads. It can manifest as precocious puberty, and is caused by abnormally high levels of testosterone or estrogen, crucial hormones for sexual development. In some cases, it may be caused by a tumor, which can be malignant, but is more commonly benign. Anabolic steroids may also be a major cause of high androgen and estrogen functional activity. Other possible causes include head injuries and brain inflammatory diseases. Hypergonadism may contribute to symptoms such as precocious puberty and abnormal facial hair growth in females.
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a female, the testicles in a male. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Before puberty, the external sex organs, known as primary sexual characteristics, are sex characteristics that distinguish males and females. Puberty leads to sexual dimorphism through the development of the secondary sex characteristics, which further distinguish the sexes.
Xenohormones or environmental hormones are compounds produced outside of the human body which exhibit endocrine hormone-like properties. They may be either of natural origin, such as phytoestrogens, which are derived from plants, or of synthetic origin. These compounds can cause endocrine disruption by multiple mechanisms including acting directly on hormone receptors, affecting the levels of natural hormones in the body, and by altering the expression of hormone receptors. The most commonly occurring xenohormones are xenoestrogens, which mimic the effects of estrogen. Other xenohormones include xenoandrogens and xenoprogesterones. Xenohormones are used for a variety of purposes including contraceptive & hormonal therapies, and agriculture. However, exposure to certain xenohormones early in childhood development can lead to a host of developmental issues including infertility, thyroid complications, and early onset of puberty. Exposure to others later in life has been linked to increased risks of testicular, prostate, ovarian, and uterine cancers.
Hypergonadotropic hypogonadism (HH), also known as primary or peripheral/gonadal hypogonadism or primary gonadal failure, is a condition which is characterized by hypogonadism which is due to an impaired response of the gonads to the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), and in turn a lack of sex steroid production. As compensation and the lack of negative feedback, gonadotropin levels are elevated. Individuals with HH have an intact and functioning hypothalamus and pituitary glands so they are still able to produce FSH and LH. HH may present as either congenital or acquired, but the majority of cases are of the former nature. HH can be treated with hormone replacement therapy.
Gonadotropin-releasing hormone (GnRH) insensitivity also known as Isolated gonadotropin-releasing hormone (GnRH)deficiency (IGD) is a rare autosomal recessive genetic and endocrine syndrome which is characterized by inactivating mutations of the gonadotropin-releasing hormone receptor (GnRHR) and thus an insensitivity of the receptor to gonadotropin-releasing hormone (GnRH), resulting in a partial or complete loss of the ability of the gonads to synthesize the sex hormones. The condition manifests itself as isolated hypogonadotropic hypogonadism (IHH), presenting with symptoms such as delayed, reduced, or absent puberty, low or complete lack of libido, and infertility, and is the predominant cause of IHH when it does not present alongside anosmia.
Hypogonadotropic hypogonadism (HH), is due to problems with either the hypothalamus or pituitary gland affecting the hypothalamic-pituitary-gonadal axis. Hypothalamic disorders result from a deficiency in the release of gonadotropic releasing hormone (GnRH), while pituitary gland disorders are due to a deficiency in the release of gonadotropins from the anterior pituitary. GnRH is the central regulator in reproductive function and sexual development via the HPG axis. GnRH is released by GnRH neurons, which are hypothalamic neuroendocrine cells, into the hypophyseal portal system acting on gonadotrophs in the anterior pituitary. The release of gonadotropins, LH and FSH, act on the gonads for the development and maintenance of proper adult reproductive physiology. LH acts on Leydig cells in the male testes and theca cells in the female. FSH acts on Sertoli cells in the male and follicular cells in the female. Combined this causes the secretion of gonadal sex steroids and the initiation of folliculogenesis and spermatogenesis. The production of sex steroids forms a negative feedback loop acting on both the anterior pituitary and hypothalamus causing a pulsatile secretion of GnRH. GnRH neurons lack sex steroid receptors and mediators such as kisspeptin stimulate GnRH neurons for pulsatile secretion of GnRH.
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, reduced or absent puberty, amenorrhea, and infertility in females, whereas males present merely with varying degrees of infertility and associated symptoms.
Premature thelarche (PT) is a medical condition, characterised by isolated breast development in female infants. It occurs in females younger than 8 years, with the highest occurrence before the age of 2. PT is rare, occurring in 2.2-4.7% of females aged 0 to 2 years old. The exact cause of the condition is still unknown, but it has been linked to a variety of genetic, dietary and physiological factors.
Kisspeptin, neurokinin B, and dynorphin (KNDy) neurons are neurons in the hypothalamus of the brain that are central to the hormonal control of reproduction.
The estrogen provocation test, also known as the estrogen stimulation test or estrogen challenge test, is a diagnostic procedure used to evaluate the function of the hypothalamic–pituitary–gonadal axis. It involves the administration of a large amount of estrogen, resulting in estrogenic exposure similar to or greater than normal preovulatory estradiol levels, in an attempt to induce a positive feedback surge in levels of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Estrogens that have been used in the estrogen provocation test include estradiol benzoate, estradiol valerate, ethinylestradiol, and high-dose transdermal estradiol patches. The test involves sustained estrogenic exposure equivalent to estradiol levels of 200 to 300 pg/mL or more for at least 50 hours and results in a surge in gonadotropin levels about 32 to 72 hours following initiation of estrogenic exposure. Levels of LH and FSH increase during the gonadotropin surge by about 10-fold and 4-fold, respectively.
References
- 1 2 3 4 5 6 7 8 Lucaccioni, Laura; Trevisani, Viola; Boncompagni, Alessandra; Marrozzini, Lucia; Berardi, Alberto; Iughetti, Lorenzo (2021-01-18). "Minipuberty: Looking Back to Understand Moving Forward". Frontiers in Pediatrics. 8. doi: 10.3389/fped.2020.612235 . ISSN 2296-2360. PMC 7848193 . PMID 33537266.
- 1 2 3 4 5 6 Becker, Marianne; Hesse, Volker (2020-06-29). "Minipuberty: Why Does it Happen?". Hormone Research in Paediatrics. 93 (2): 76–84. doi:10.1159/000508329. ISSN 1663-2818. PMID 32599600.
- ↑ Nordenström, Anna (2022-08-01). "Potential impact of mini-puberty on fertility". Annales d'Endocrinologie. 83 (4): 250–253. doi:10.1016/j.ando.2022.06.002. ISSN 0003-4266. PMID 35728696.
- ↑ Grumbach, Melvin M. (May 2005). "A Window of Opportunity: The Diagnosis of Gonadotropin Deficiency in the Male Infant 1". The Journal of Clinical Endocrinology & Metabolism. 90 (5): 3122–3127. doi:10.1210/jc.2004-2465. ISSN 0021-972X. PMID 15728198.
- ↑ Quinton, Richard; Mamoojee, Yaasir; Jayasena, Channa N.; Young, Jacques; Howard, Sasha; Dunkel, Leo; Cheetham, Tim; Smith, Neil; Dwyer, Andrew A. (February 2017). "Society for Endocrinology UK guidance on the evaluation of suspected disorders of sexual development: emphasizing the opportunity to predict adolescent pubertal failure through a neonatal diagnosis of absent minipuberty". Clinical Endocrinology. 86 (2): 305–306. doi:10.1111/cen.13257. ISSN 0300-0664. PMID 27749014.
- ↑ Rohayem, Julia; Alexander, Emma C; Heger, Sabine; Nordenström, Anna; Howard, Sasha R (2024-03-04). "Mini-Puberty, Physiological and Disordered: Consequences, and Potential for Therapeutic Replacement". Endocrine Reviews. 45 (4): 460–492. doi:10.1210/endrev/bnae003. ISSN 0163-769X. PMC 11244267 . PMID 38436980.
- ↑ Dwyer, Andrew A. (January 2020). "Minipuberty: A Primer for Pediatric Nurses". Journal of Pediatric Nursing. 50: 138–139. doi:10.1016/j.pedn.2019.10.012. ISSN 0882-5963. PMID 31874718.
- ↑ Ünüvar, Tolga; Büyükgebiz, Atilla (2012-04-15). "Fetal and Neonatal Endocrine Disruptors" (PDF). Journal of Clinical Research in Pediatric Endocrinology. 4 (2): 51–60. doi:10.4274/Jcrpe.569. PMC 3386773 . PMID 22672860.
- 1 2 Winneke, Gerhard; Ranft, Ulrich; Wittsiepe, Jürgen; Kasper-Sonnenberg, Monika; Fürst, Peter; Krämer, Ursula; Seitner, Gabriele; Wilhelm, Michael (March 2014). "Behavioral Sexual Dimorphism in School-Age Children and Early Developmental Exposure to Dioxins and PCBs: A Follow-Up Study of the Duisburg Cohort". Environmental Health Perspectives. 122 (3): 292–298. doi:10.1289/ehp.1306533. ISSN 0091-6765. PMC 3948031 . PMID 24273228.
- ↑ Sun, Xiaowei; Li, Dekun; Liang, Hong; Miao, Maohua; Song, Xiuxia; Wang, Ziliang; Zhou, Zhijun; Yuan, Wei (December 2018). "Maternal exposure to bisphenol A and anogenital distance throughout infancy: A longitudinal study from Shanghai, China". Environment International. 121 (Pt 1): 269–275. Bibcode:2018EnInt.121..269S. doi: 10.1016/j.envint.2018.08.055 . PMID 30223203.
- ↑ Muerköster, Anna-Patricia; Frederiksen, Hanne; Juul, Anders; Andersson, Anna-Maria; Jensen, Richard Christian; Glintborg, Dorte; Kyhl, Henriette Boye; Andersen, Marianne Skovsager; Timmermann, Clara Amalie Gade; Jensen, Tina Kold (November 2020). "Maternal phthalate exposure associated with decreased testosterone/LH ratio in male offspring during mini-puberty. Odense Child Cohort". Environment International. 144: 106025. Bibcode:2020EnInt.14406025M. doi:10.1016/j.envint.2020.106025. PMID 32798799.
- ↑ Lærkeholm Müller, Matilde; Busch, Alexander Siegfried; Ljubicic, Marie Lindhardt; Upners, Emmie N.; Fischer, Margit B.; Hagen, Casper P.; Albrethsen, Jakob; Frederiksen, Hanne; Juul, Anders; Andersson, Anna-Maria (2023-05-01). "Urinary concentration of phthalates and bisphenol A during minipuberty is associated with reproductive hormone concentrations in infant boys". International Journal of Hygiene and Environmental Health. 250: 114166. Bibcode:2023IJHEH.25014166L. doi: 10.1016/j.ijheh.2023.114166 . ISSN 1438-4639. PMID 37058994.
- ↑ Palioura, Eleni; Diamanti-Kandarakis, Evanthia (December 2015). "Polycystic ovary syndrome (PCOS) and endocrine disrupting chemicals (EDCs)". Reviews in Endocrine and Metabolic Disorders. 16 (4): 365–371. doi:10.1007/s11154-016-9326-7. ISSN 1389-9155. PMID 26825073.
- ↑ Burks, Hope; Pashos, Nicholas; Martin, Elizabeth; Mclachlan, John; Bunnell, Bruce; Burow, Matthew (December 2017). "Endocrine disruptors and the tumor microenvironment: A new paradigm in breast cancer biology". Molecular and Cellular Endocrinology. 457: 13–19. doi:10.1016/j.mce.2016.12.010. PMID 28012841.
- ↑ Avril, Tristan; Hennocq, Quentin; Lambert, Anne-Sophie; Leger, Juliane; Simon, Dominique; Martinerie, Laetitia; Bouvattier, Claire (2023-04-01). "Gonadotropin administration to mimic mini-puberty in hypogonadotropic males: pump or injections?". Endocrine Connections. 12 (4). doi:10.1530/EC-22-0252. ISSN 2049-3614. PMC 10083662 . PMID 36724045.