{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T19:05:18Z","timestamp":1791918318125,"version":"4.3.4"},"reference-count":36,"publisher":"American Physiological Society","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Regulatory, Integrative and Comparative Physiology"],"published-print":{"date-parts":[[2007,1]]},"abstract":"<jats:p> The slowly maturing, long-lived rodent Octodon degus (degu) provides a unique opportunity to examine the development of the circadian system during adolescence. These studies characterize entrained and free-running activity rhythms in gonadally intact and prepubertally gonadectomized male and female degus across the first year of life to clarify the impact of sex and gonadal hormones on the circadian system during adolescence. Gonadally intact degus exhibited a delay in the phase angle of activity onset (\u03a8<jats:sub>on<\/jats:sub>) during puberty, which reversed as animals became reproductively competent. Gonadectomy before puberty prevented this phase delay. However, the effect of gonadal hormones during puberty on \u03a8<jats:sub>on<\/jats:sub> does not result from changes in the period of the underlying circadian pacemaker. A sex difference in \u03a8<jats:sub>on<\/jats:sub> and free-running period (\u03c4) emerged several months after puberty; these developmental changes are not likely to be related, since the sex difference in \u03a8<jats:sub>on<\/jats:sub> emerged before the sex difference in \u03c4. Changes in the levels of circulating hormones cannot explain the emergence of these sex differences, since there is a rather lengthy delay between the age at which degus reach sexual maturity and the age at which \u03a8<jats:sub>on<\/jats:sub> and \u03c4 become sexually dimorphic. However, postnatal exposure to gonadal hormones is required for sexual differentiation of \u03a8<jats:sub>on<\/jats:sub> and \u03c4, since these sex differences were absent in prepubertally gonadectomized degus. These data suggest that gonadal hormones modulate the circadian system during adolescent development and provide a new model for postpubertal sexual differentiation of a central nervous system structure. <\/jats:p>","DOI":"10.1152\/ajpregu.00043.2006","type":"journal-article","created":{"date-parts":[[2006,8,17]],"date-time":"2006-08-17T21:10:12Z","timestamp":1155849012000},"page":"R586-R597","source":"Crossref","is-referenced-by-count":45,"title":["Gonadal hormone effects on entrained and free-running circadian activity rhythms in the developing diurnal rodent <i>Octodon degus<\/i>"],"prefix":"10.1152","volume":"292","author":[{"given":"Daniel L.","family":"Hummer","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tammy J.","family":"Jechura","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Megan M.","family":"Mahoney","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Theresa M.","family":"Lee","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"R1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.1981.241.1.R62"},{"key":"R2","doi-asserted-by":"publisher","DOI":"10.1196\/annals.1308.032"},{"key":"R3","doi-asserted-by":"publisher","DOI":"10.1177\/074873049701200309"},{"key":"R4","doi-asserted-by":"publisher","DOI":"10.1093\/sleep\/2.4.453"},{"key":"R5","doi-asserted-by":"publisher","DOI":"10.1093\/sleep\/16.3.258"},{"key":"R6","doi-asserted-by":"publisher","DOI":"10.1093\/sleep\/21.8.871"},{"key":"R7","doi-asserted-by":"publisher","DOI":"10.1126\/science.284.5423.2177"},{"key":"R8","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3940(99)00519-4"},{"key":"R9","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3940(01)02427-2"},{"key":"R10","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2869.2002.00302.x"},{"key":"R11","unstructured":"Gill G, Frost J, and Miller K. A new formula for a half-oxidized hematoxylin solution that neither overstains nor requires differentiation. Acta Cytol 18: 300\u2013311, 1974."},{"key":"R12","doi-asserted-by":"publisher","DOI":"10.1530\/jrf.0.0390337"},{"key":"R13","doi-asserted-by":"publisher","DOI":"10.1093\/cercor\/11.8.717"},{"key":"R14","doi-asserted-by":"publisher","DOI":"10.1016\/S0306-4522(01)00201-9"},{"key":"R15","doi-asserted-by":"publisher","DOI":"10.1016\/0165-3806(91)90125-3"},{"key":"R16","unstructured":"Jechura TJ. Sex Differences in Circadian Rhythms: Effects of Gonadal Hormones in Octodon degus (Ph.D. thesis). Ann Arbor: University of Michigan, 2002."},{"key":"R17","doi-asserted-by":"publisher","DOI":"10.1006\/hbeh.2000.1624"},{"key":"R18","doi-asserted-by":"publisher","DOI":"10.1016\/0031-9384(95)00096-2"},{"key":"R19","doi-asserted-by":"publisher","DOI":"10.1677\/joe.0.0950137"},{"key":"R20","doi-asserted-by":"publisher","DOI":"10.1093\/ilar.45.1.14"},{"key":"R21","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.1997.273.1.R278"},{"key":"R22","unstructured":"Miller RG. Simultaneous Statistical Inference. New York: McGraw-Hill, 1966."},{"key":"R23","unstructured":"Monk TH and Zee PC. Circadian rhythms, aging and dementia. In: Handbook of Behavioral Neurobiology, edited by Takahashi JS, Turek FW, and Moore RY. New York: Kluwer Academic\/Plenum, 2001, p. 603\u2013623."},{"key":"R24","doi-asserted-by":"publisher","DOI":"10.1126\/science.557840"},{"key":"R25","doi-asserted-by":"publisher","DOI":"10.1016\/S0306-4522(01)00059-8"},{"key":"R26","doi-asserted-by":"publisher","DOI":"10.1016\/S0306-4522(00)00190-1"},{"key":"R27","doi-asserted-by":"publisher","DOI":"10.1016\/S0306-4522(02)00751-0"},{"key":"R28","doi-asserted-by":"publisher","DOI":"10.1002\/neu.20070"},{"key":"R29","doi-asserted-by":"publisher","DOI":"10.1016\/j.cub.2004.11.039"},{"key":"R30","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.1997.272.4.R1219"},{"key":"R31","doi-asserted-by":"publisher","DOI":"10.1016\/j.yhbeh.2003.12.007"},{"key":"R32","unstructured":"Tate BA, Richardson GS, and Carskadon MA. Maturational changes in sleep-wake timing: longitudinal studies of the circadian activity rhythm of a diurnal rodent. In: Adolescent Sleep Patterns: Biological, Social, and Psychological Influences, edited by Carskadon MA. New York: Cambridge University Press, 2002, p. 40\u201349."},{"key":"R33","unstructured":"Turek FW, Scarbrough K, Penev P, Labyak S, Valentinuzzi VS, and Van Reeth O. Aging of the mammalian circadian system. In: Handbook of Behavioral Neurobiology, edited by Takahashi JS, Turek FW, and Moore RY. New York: Kluwer Academic\/Plenum, 2001, p. 291\u2013317."},{"key":"R34","unstructured":"Weir BJ. Reproductive characteristics of hystricomorph rodents. Symp Zool Soc Lond 34: 265\u2013301, 1974."},{"key":"R35","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.1992.263.5.R1099"},{"key":"R36","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.1980.238.1.R97"}],"container-title":["American Journal of Physiology-Regulatory, Integrative and Comparative Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.physiology.org\/doi\/pdf\/10.1152\/ajpregu.00043.2006","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,9,8]],"date-time":"2019-09-08T11:36:39Z","timestamp":1567942599000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.physiology.org\/doi\/10.1152\/ajpregu.00043.2006"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,1]]},"references-count":36,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2007,1]]}},"alternative-id":["10.1152\/ajpregu.00043.2006"],"URL":"https:\/\/doi.org\/10.1152\/ajpregu.00043.2006","relation":{},"ISSN":["0363-6119","1522-1490"],"issn-type":[{"value":"0363-6119","type":"print"},{"value":"1522-1490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,1]]}}}