Exogenous melatonin modifies the circadian rhythm but does not increase the level of some immune parameters in the chicken.

摘要: : The effect of daily injections the pineal hormone melatonin and naltrexone, an opioid antagonist, on circadian rhythm level immune parameters (plaque forming cell [PFC] number, serum agglutinin titer, lymphoid gland weight, total white blood cells (WBC) their fraction lysozyme [LZ] content) was examined in White Leghorn cockerels female BALB/c mice kept LD 12:12. Animals were immunized ip with sheep red (SRBC) to stimulate system. Subcutaneous melatonin, or both drugs together made 2 hr before end light, for 4 5 days, beginning day immunization. following fifth injection, chickens sacrificed over a 24 period every (experiment I) twice daily, i.e., at light dark phases II). Mice killed fourth injection splenic PFC number determined III). In experiment I, existence diurnal evaluated by cosinor analysis. Melatonin entrained anti-SRBC agglutinins, but it did not influence rhythmicity other examined. WBC fractions naltrexone treatment. affect either mean weight organs. Splenic diminished injections, whereas increased antagonized that effect. It is concluded chickens, least dose range used, immunoenhancing agent, as mice. Possible reasons this difference are discussed.