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Key Event: 2415

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Precocious puberty

Short name
The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. More help
Precocious puberty
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Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help
Level of Biological Organization
Individual

Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; https://aopwiki.org/info_pages/2/info_linked_pages/7#List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling).  The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor).  Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description.  To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons.  If a desired term does not exist, a new term request may be made via Term Requests.  Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add.  Further information on Event Components and Biological Context may be viewed on the attached pdf. More help
Process Object Action
abnormal reproductive system development reproductive organ increased

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help
AOP Name Role of event in AOP Point of Contact Author Status OECD Status
Activation, ERα leads to precocious puberty via increased kisspeptin AdverseOutcome John Frisch (send email) Under development: Not open for comment. Do not cite

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help
Term Scientific Term Evidence Link
Vertebrates Vertebrates Moderate NCBI

Life Stages

An indication of the the relevant life stage(s) for this KE. More help
Life stage Evidence
Juvenile Moderate
Adult, reproductively mature Moderate

Sex Applicability

An indication of the the relevant sex for this KE. More help
Term Evidence
Unspecific High

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

Puberty occurs when reproductive organs mature and hormone levels are altered to transform an individual into capable of reproduction (for review McCormick et al. 2017).  Puberty is a process that all vertebrate species undergo in order to become sexually mature, but has been mainly studied in mammals (Ball and Wade 2013). In rodent females, puberty includes the onset of the estrus cycle (for review see Miller and Takahashi 2014; Swift et al. 2024).  Precocious puberty occurs when stressors accelerate the process of sexual maturation, with associated physiological and hormone changes.

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

Puberty is generally assessed by physiological changes in an individual.  In rodents vaginal opening in females and balanopreputial separation (separation of the foreskin from penis) in males are often used as visual indicators of onset of puberty (e.g. Engelbregt et al. 2001).  In birds there can be species-specific changes such as feather plumage, eye color, skull ossification, feather wear, and eye color (Mueller and Weise 1996; Cucco and Malacarne 2000).  Size (body weight or length) is generally a better predictor of maturity than age in reptiles (Ball and Wade 2013; Marn and Kooijman 2022), amphibians (Ryser 1996; Morrison and Hero 2003), and fish (Ryu et al. 2013; Espigares et al. 2015), with a threshold minimum size for reproduction.  Determining an individual has mature ova or sperm or changes in hormone levels from baseline (i.e. gonadotropins, testosterone, estradiol) are more invasive but alternative assessment methods, with development of mature ova or sperm ultimately a more direct assessment of the onset of puberty.

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided).  More help

Life Stage: Adult, reproductively mature, juveniles undergoing reproductive maturation.

Sex: Applies to both males and females as both sexes undergo reproductive maturation.

Taxonomic: Primarily studied in laboratory rodents and humans.  Plausible for most mammals and vertebrates due to shared reproductive physiology and hormones.  

Regulatory Significance of the Adverse Outcome

An AO is a specialised KE that represents the end (an adverse outcome of regulatory significance) of an AOP. More help

References

List of the literature that was cited for this KE description. More help

Ball GF, Wade J. 2013.  The value of comparative approaches to our understanding of puberty as illustrated by investigations in birds and reptiles. Hormones and Behavior 64(2): 211-214. 

Cucco M, Malacarne G.  2000.  Delayed maturation in passerine birds: an examination of plumage effects and some indications of a related effect in song.  Ethology Ecology and Evolution 12: 291-308.

Engelbregt MJ, van Weissenbruch MM, Popp-Snijders C, Lips P, Delemarre-van de Waal HA. 2001. Body mass index, body composition, and leptin at onset of puberty in male and female rats after intrauterine growth retardation and after early postnatal food restriction. Pediatric Research 50(4): 474-478.

Espigares F, Rocha A, Moles G, Gomez A, Carrillo M, Zanuy S. 2015. New insights into the factors mediating the onset of puberty in sea bass. General and Comparative Endocrinology 224: 176-185. 

Marn N, Kooijman SALM. 2022. The comparative energetics of the turtles and crocodiles. Ecology and Evolution 12(6): e8996.

McCormick CM, Green MR, Simone JJ. 2017.  Translational relevance of rodent models of hypothalamic-pituitary-adrenal function and stressors in adolescence. Neurobiology of Stress 6: 31-43. 

Miller, BH and Takahashi, J.  2014.  Central circadian control of female reproductive function.  Frontiers in Endocrinology 4(1): 195.

Morrison, C, Hero, J-M.  2003.  Geographic variation in life-history characteristics of amphibians: a review.  Journal of Animal Ecology 72: 270–279.

Mueller, WP, Weise, CM 1996. An assessment of age determination methods for captured passerine birds. Field Station Bulletin 29(1): 21-27.

Ryser, J. 1996.  Comparative life histories of a low- and a high-elevation population of the common frog Rana temporaria. Amphibia–Reptilia 17: 183–195.

Ryu YW, Hur SW, Hur SP, Lee CH, Lim BS, Lee YD. 2013.  Characterization of Pubertal Development Phases in Female Longtooth Grouper, Epinephelus bruneus via Classification of Bodyweight. Development and Reproduction 17(1): 55-62.

Swift, KM, Gary, NC, and Urbanczyk, PJ.  2024.  On the basis of sex and sleep: the influence of the estrous cycle and sex on sleep-wake behavior.  Frontiers in Neuroscience 18:1426189.

NOTE: Italics indicate edits from John Frisch March 2026.  A full list of updates can be found in the Change Log on the View History page.