All of the following factors are involved in altered patterns of hormone release except

A patient in the intensive care unit, where the lights are on throughout the 24 hours of the day, will have a disrupted cycle of hormone release. Light plays an impoant role in generating the circadian rhythm of hormone secretion. This endogenous rhythm is generated through the interaction between the retina, the hypothalamic suprachiasmatic nucleus, and the pineal gland through the release of melatonin. Melatonin is a hormone synthesized and secreted by the pineal gland at night. Its rhythm of secretion is entrained to the light/dark cycle. Melatonin conveys information concerning the daily cycle of light and darkness to the body and paicipates in the organization of circadian rhythms. Other situations that disrupt the normal cycles of hormone release are travel across time zones, night-shift employment, and aging.