Age, reproductive and menopausal factors, body mass index (BMI), alcohol consumption, smoking history, night shift work were significantly related to lower levels of melatonin, whereas parity was significantly associated with higher aMT6s levels.

Exposure to magnetic fields is associated with decressed nocturnalmelatonin levels, but does not support the hypothesis that such exposure results in increased urinary levels of estrogens, LH, or FSH.

Melatonin (0.125, 0.25, 0.50 or 1.0 mg melatonin/ day/rat subcutaneously at 17:30-18:00 hr.) inhibits the proliferation and induces apoptosis of rat pituitary prolactin-secreting tumor via perturbation of mitochondria physiology.

RAS in pineal gland is modified in rats with breast cancer induced by NMU (N-methyl nitrosourea) through the inhibition of AspAP (Aspartyl aminopeptidase) activity, which may lead to increased levels of Ang II (angiotensin II).

No abstract available.

No abstract available.

Nocturnal rodents are frequently used as models in C human breast cancer research, the circadian systems of nocturnal rodents are approximately 10,000 times moresensitive toopticalradiation than that ofhumans.

Circadian disruption could lead to alterations in melatonin production and can increase breast tumorigenesis in experimental animals. Exogenous administration of melatonin has been shown to phase shift humans depending on the time of day it's given.

The circadian rhythm for pineal melatonin secretion is regulated by the hypothalamic suprachiasmatic nucleus (SCN).Action spectra of melatonin suppression by light have shown that light in the 446-477 nm range,higher risk of breast cancer in industrialized countries is partly due to increased exposure to light at night.