Light contamination during the dark phase in "photoperiodically controlled" animal rooms: effect on tumor growth and metabolism in rats.

摘要: Enhanced neoplastic growth and metabolism have been reported in animals maintained a constant light (24L:0D) environment. Results from this laboratory indicate that tumor is directly dependent upon increased ambient blood concentrations of arachidonic linoleic acids, particularly acid. Tumor acid utilization production if its putative mitogenic metabolite, 13-hydroxyoctadecadienoic (13-HODE), are suppressed by the circadian neurohormone melatonin, which itself regulated all mammals. This study was performed to determine whether minimal contamination (0.2 lux) an animal room during otherwise normal dark phase may disrupt melatonin affect metabolism. Animals groups I (12L:12D), II (12L:12-h light-contaminated phase), III had plasma total fatty (TFA), (LA), measured prior implantation; daily cycles TFA LA values, whereas group values throughout day. The integrated mean for entire day were similar groups. Although group-I nocturnal surge (127.0 pg/ml) at 2400 h, amplitude group-II (16.0 pg/ml); variation concentration not seen group-III (7.4 pg/ml). At 12 weeks age, rats Morris hepatoma 7288CTC implanted as "tissue-isolated" tumors grown subcutaneously. Latency onset palpable mass I, II, 11, 9, 5 days respectively. rates 0.72 +/- 0.09, 1.30 0.15, 1.48 0.17 g/d (mean SD, n = 6/group) Arteriovenous difference measurements across 4.22 0.89 0.83 0.18 (group I), 8.26 0.66 1.64 0.13 II), 7.10 0.78 1.50 0.16 III)/min/g, significantly different (P < 0.05). contents 14.3 1.7 1.8 0.3 52.9 5.5 7.9 0.8 106.0 12.0 18.5 2.4 III) micrograms/g each other 0.001). Production 13-HODE hepatomas 35.5 6.3, 109.6 10.6, 196.2 34.9 ng/min/g respectively, also among results only 0.2 lux inhibits host secretion increases rate lipid uptake These data suggest great care must be taken prevent "light-leaks" rooms diurnal cycle because such adversely outcome investigations.