Circadian rhythm of lactate dehydrogenase in rat testis.
Activity of total lactate dehydrogenase (LDH) and of the isozyme X (LDH X or C4) have been determined at 2 hr intervals during 24 hr cycles in testis of adult rats maintained since birth in a photoperiod of 14 hr light: 10 hr dark. LDH X activity of epididymal sections (caput, corpus and cauda) from the same animals was also determined. Total LDH and LDH X activities in testis exhibited circadian rhythms with different timing. LDH X in the three portions of epididymis showed diurnal variations similar to those in testis. Rats subjected to constant light or constant dark presented marked modifications of LDH X profiles, indicating that the photoperiod plays a synchronizer role. While total soluble proteins did not show variations in testis of rats exposed to the photoperiod, a circadian rhythm was demonstrated in animals maintained in constant light or dark.
D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008297:Male; D010775:Photic Stimulation; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000201:enzymology*
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase