Fig. 7.

Diurnal changes in retinoic acid signaling genes, Rarg and Rdh12, persist in constant darkness in the rat pineal gland. qPCR analysis of expression of retinoic acid signaling genes in pineal glands of Sprague Dawley rats maintained in constant darkness for 2 days. Pineal glands were collected at different circadian times (CT) throughout a 24 h cycle; CT0 and CT12 correspond to subjective light on and light off, respectively; horizontal black bar and grey shading indicate the dark period. Values represent mean mRNA expression relative to Gapdh, ± SEM. N = 5 glands per time-point. **P < 0.01; ***P < 0.001