Cagnacci A, Soldani R, Yen S S
Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla 92093-0802.
J Appl Physiol (1985). 1995 Jan;78(1):314-7. doi: 10.1152/jappl.1995.78.1.314.
In young humans, the nocturnal rise of the hypothermic hormone melatonin generates 40-50% of the circadian core body temperature (Tc) decline. The nocturnal Tc decline is reduced with aging in men. In this study we investigated whether a similar attenuation occurs in women and whether it is associated with a reduced serum concentration and/or action of melatonin. The circadian rhythms of melatonin and Tc (measured in the vagina) and the responses of both Tc (measured into the auricolar canal) and finger skin temperature to melatonin administration (100 mg at 0800) were investigated in two experiments involving young (22-32 yr) and aged (54-62 yr) women. In aged women, the nocturnal onset of the melatonin rise was phase advanced and Tc decline and Tc rhythm amplitude were reduced (P < 0.0005). The serum melatonin concentrations in aged women were similar to those of young women, but the melatonin capability to reduce Tc and increase skin temperature was markedly impaired. Our data show that, in women, an aging-associated reduction of temperature responses to melatonin is probably involved in inducing an attenuation of the nocturnal Tc decline and circadian Tc rhythm amplitude.
在年轻人群中，降温激素褪黑素的夜间升高导致昼夜核心体温（Tc）下降的40%-50%。男性的夜间Tc下降会随着年龄增长而减少。在本研究中，我们调查了女性是否也会出现类似的减弱情况，以及这是否与血清褪黑素浓度降低和/或褪黑素作用减弱有关。在两项实验中，我们研究了年轻（22-32岁）和老年（54-62岁）女性的褪黑素和Tc（在阴道测量）的昼夜节律，以及Tc（在耳道测量）和手指皮肤温度对褪黑素给药（08:00给予100毫克）的反应。在老年女性中，褪黑素升高的夜间起始相位提前，Tc下降和Tc节律幅度降低（P<0.0005）。老年女性的血清褪黑素浓度与年轻女性相似，但褪黑素降低Tc和升高皮肤温度的能力明显受损。我们的数据表明，在女性中，与衰老相关的对褪黑素温度反应的降低可能参与导致夜间Tc下降和昼夜Tc节律幅度的减弱。
