{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T12:26:42Z","timestamp":1782995202253,"version":"3.54.5"},"reference-count":55,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,7,14]],"date-time":"2022-07-14T00:00:00Z","timestamp":1657756800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000289","name":"Cancer Research UK","doi-asserted-by":"publisher","award":["C19767\/A27145"],"award-info":[{"award-number":["C19767\/A27145"]}],"id":[{"id":"10.13039\/501100000289","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:p>Every menstrual cycle, many follicles begin to develop but only a specific number ovulate. This ovulation number determines how many offspring are produced per litter, and differs between species. The physiological mechanism that controls ovulation number is unknown; a class of mathematical models can explain it, but these models have no physiological basis. Here, we suggest a physiological mechanism for ovulation number control, which enables selection of a specific number of follicles out of many, and analyze it in a mathematical model of follicular growth. The mechanism is based on a signal, intra-follicular androgen concentration, that measures follicle size relative to the other follicles. This signal has a biphasic effect, suppressing follicles that are too large or too small compared to others. The ovulation number is determined by the androgen inhibitory thresholds. The model has a scaling symmetry that explains why the dominant follicles grow linearly with time, as observed in human ultrasound data. This approach also explains how chronic hyperandrogenism disrupts ovulation in polycystic ovary syndrome (PCOS), a leading cause of infertility. We propose specific experiments for testing the proposed mechanism.<\/jats:p>","DOI":"10.3389\/fendo.2022.816967","type":"journal-article","created":{"date-parts":[[2022,7,14]],"date-time":"2022-07-14T06:47:48Z","timestamp":1657781268000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":8,"title":["A Mechanism for Ovulation Number Control"],"prefix":"10.3389","volume":"13","author":[{"given":"Michal","family":"Shilo","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Avi","family":"Mayo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Uri","family":"Alon","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,7,14]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1016\/S0015-0282(03)00544-2","article-title":"A New Model for Ovarian Follicular Development During the Human Menstrual Cycle","volume":"80","author":"Baerwald","year":"2003","journal-title":"Fert Steril"},{"key":"B2","doi-asserted-by":"publisher","first-page":"2014","DOI":"10.1186\/s13048-014-0102-6","article-title":"Ultrastructural Changes in Oocytes During Folliculogenesis in Domestic Mammals","volume":"7","author":"Paulini","year":"","journal-title":"J Ovarian Res"},{"key":"B3","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/B978-0-323-47912-7.00008-1","article-title":"\u201cChapter 8 - Ovarian Life Cycle,\u201d","volume-title":"Yen and Jaffe\u2019s Reproductive Endocrinology (Eighth Edition)","author":"Strauss","year":"2019"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1016\/S0006-3495(81)84800-X","article-title":"Regulation of Ovulation Number in Mammals. 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