Table 1.
A delay in circadian phase has been observed around the time of puberty in six mammalian species
Species |
||||||
---|---|---|---|---|---|---|
human (Homo sapiens) | rhesus monkey (Macaca mulatta) | degu (Octodon degus) | laboratory rat (Rattus norvegicus) | laboratory mouse (Mus musculus) | fat sand rat (Psammomys obesus) | |
Magnitude of delay | 1–3 h | 2 h | 3–5 h | 1–4 h | 1 h? | 0–3 h under a long photoperiod∗, 10–14 h under a short photoperiod |
Sex difference | males > females | only females examined | males > females | males > females | only females examined | sex unspecified |
Rhythms delayed | sleep, melatonin | activity | activity, sleep? | activity | activity, corticosterone, temperature?∗ | oxygen consumption, temperature |
No. of experiments | >20 | 1 | 6 | 4 | 2 | 1 |
Age of peak delay | 15–21 years | 39 months | 80–100 days | 30–40 days | unknown, but delay evident at 35–45 days | unknown, but delay evident at 35–42 days |
Age of establishing overt cyclicity in females | menarche: 12–13 years regular ovulation: 13–16 years [21] | menarche: 30–33 months first ovulation: 42–45 months [12] | cycles in vaginal opening: 35–150 days [13, 16] | first ovulation: 35–45 days [22] | first ovulation: 27–40 days regular ovulation: 30–80 days [23, 24] | unknown |
Age of establishing spermatogenesis | 12–16 years [21] | n/a | 60–120 days [13] | 45–65 days [22] | n/a | 28–56 days [25] |
Gonadal dependent | maybe | unknown | maybe | maybe | unknown | unknown |
Circadian citations | reviewed in [4, 8] | [12] | [13, 14, 15, 16] | [16, 17] | [18, 19] | [20] |