Diurnal rhythm

Diurnal rhythms, both in P450 levels and in the susceptibility to toxicants, have been described, especially in rodents. Although such changes appear to be related to the light cycle, they may in fact be activity dependent because feeding and other activities in rodents are themselves markedly diurnal. 

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Bruinink A., Lichtensteiger W., Schlumpf M. (1983). Ontogeny of diurnal rhythms of central dopamine, serotonin and spirodecanone binding sites and of motor activity in the rat. Life Sci. 33(1), 31-8. 

Evans H. L., Ghiselli W. B., Patton R. A. (1973). Diurnal rhythm in behavioral effects of methamphetamine, p-chloramethamphetamine and scopolamine. J. 

Freeman A., Morales J., Beck J. et al. (2006). In vivo diurnal rhythm of dopamine measured in the putamen of non-human primates. Sleep 29(Abstr. Suppl.), A69. 

Lemmer B., Berger T. (1978). Diurnal rhythm in the central dopamine turnover in the rat. Naunyn Schmiedebergs Arch. Pharmacol 303(3), 257-61. 

Murillo-Rodriguez E., Bianco-Centurion C., Gerashchenko D., Salin-Pascual R. J., Shiromani P. J. (2004). The diurnal rhythm of adenosine levels in the basal forebrain of young and old rats. Neuroscience 123, 361-70. 

Suprachiasmatic nucleus A hypothalamic nucleus involved in the maintenance of circadian (diurnal) rhythms. 

Zhang F., Romheld V., Marschner H. Diurnal rhythm of release of phytosiderophores and uptake rate of zinc in iron-deficient wheat. Soil Sci Plant Nutri 1991 37 671-678. 

Hydrocortisone, cortisone, and prednisone are the glucocorticoids of choice, administered twice daily at the lowest effective dose while mimicking the normal diurnal rhythm of cortisol production. 

P7. Pincus, G., Diurnal rhythm in excretion of urinary ketosteroids by young men. J. Clin. Endocrinol. 3, 195-199 (1943). 

Site of alkaloid formation, transport, and accumulation. QA are formed in the aerial green parts of legumes, especially in the leaves (.9) In lupin leaves we succeeded in localizing the key enzymes of QA biosynthesis in the chloroplast (10, 11), where the formation of the precursor lysine also takes place. Like most of the processes that are located in the chloroplast, QA biosynthesis is regulated by light (.8) and QA formation fol lows a light-dependent diurnal rhythm (, 13). The alkaloids formed in the leaves are translocated via the phloem (13, 14) all over a lupin plant, so that all plant parts contain alkaloids. QA are accumulated and stored preferentially in epidermal and subepidermal tissues of stems and leaves (15, 16). Especially rich in alkaloids are the seeds, which may contain up to 5% (dry weight) alkaloid (equivalent to 200 mmol/ kg). ... 

Adverse environmental conditions or stimuli, which create stress in an animal, may influence drug metabolism and disposition. Cold stress, for instance, increases aromatic hydroxylation, as does stress due to excessive noise. It should be noted that the microsomal monooxygenases show a diurnal rhythm in both rats and mice, with the greatest activity at the beginning of the dark phase. 

Most of the luminescent systems mentioned appear to be. under some nerve control. Normally, a luminous flash is observed after mechanical or electrical stimulation of most of the aforementioned species. A number of these also exhibit a diurnal rhythm of luminescence. 

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