Fig 2.

Circadian rhythms of cultured cornea, pituitary, kidney, pineal, and PVN. Data were plotted as in Fig. 1 (A and B). Aging did not alter the robustness of circadian oscillations in cornea and pituitary. Shown are representative recordings from cornea of young (A) and aged (B) rats and pituitary from young (C) and aged (D) rats. Aging did alter the phase of kidney, pineal, and PVN. Shown are examples of circadian rhythms from kidney of young (E) and old (F), pineal from young (G) and old (H), and PVN from young (I) and old (J) animals. There was no difference in the robustness of these oscillations between young and old animals. Peak Per-luc activity in kidney and pineal cultures from aged rats were ≈4-h phase advanced compared with tissue from young rats. A sharp peak at the beginning of subjective day (J) was observed in most PVN from aged rats but not from young rats (see Results and Fig. 5 for details).