INS and glucose metabolism disease: Taking into account the rapid clearance rate of insulin (with a half-life of only 5 min), our findings revealed the following: (1) insulin production was not substantially diminished in any of the monkey groups, (2) exposure to brighter nocturnal lighting led to increased insulin resistance, and (3) there was a varying degree of susceptibility to glucose metabolic disorders among the monkeys, with those in the LID group being more susceptible.