Daily cycles of putrescine, sperrnidine, and spermine in the liver, pineal gland, Harderian gland, anterior pituitary, and testes of rats kept in LD 12:12

A circadian rhythm in cellular polyamine levels was detected in the liver, pineal gland, anterior pituitary gland, Harderian gland, and testicular seminiferous tubules of male rats fed ad libitum and maintained in a light:dark cycle of LD 12:12 (lights on at 07:00). Liver putrescine content was highest at 24:00, showing a sixfold increase over 12:00 levels. Pineal spermidine and spermine contents reached a maximum at 06:00, late in the dark phase. A similar pattern was also detected in the Harderian gland. In the anterior pituitary, the polyamines putrescine, spermidine and spermine were highest at 18:00, late in the light phase. However, the increase in putrescine was not statistically significant. The three polyamine contents decreased late in the dark phase. In testicular seminiferous tubules putrescine, on the contrary, was highest (about a twofold increase) late in the dark phase.