Romijn J A, Adriaanse R, Brabant G, Prank K, Endert E, Wiersinga W M
Department of Intensive Care, Academisch Medisch Centrum, University of Amsterdam, The Netherlands.
J Clin Endocrinol Metab. 1990 Jun;70(6):1631-6. doi: 10.1210/jcem-70-6-1631.
The effect of fasting on circadian and pulsatile TSH secretion was investigated in eight healthy subjects (four men and four women in the follicular phase). Each subject was studied twice, once during 24 h with normal food intake and once during the last 24 h of a 60-h fast. Blood was sampled every 10 min during 24 h for measurement of TSH by a sensitive immunoradiometric assay. Fasting induced a decrease in plasma T3 [1.73 +/- 0.06 vs. 1.36 +/- 0.04 nmol/L; P less than 0.01 (mean +/- SE), control period vs. fasting] and thyroglobulin (52 +/- 8 vs. 35 +/- 7 pmol/L; P less than 0.001) and an increase in plasma rT3 (0.30 +/- 0.06 vs. 0.44 +/- 0.09 nmol/L; P less than 0.02). Plasma T4, thyroid hormone binding index, and free T4 were not statistically different in both periods. The mean plasma 24-h TSH concentration was lower during fasting than in the control period (2.0 +/- 0.3 vs. 1.0 +/- 0.2 mU/L; P less than 0.005). This was associated with a decrease in mean TSH pulse amplitude during fasting (Desade program: 0.6 +/- 0.1 vs. 0.3 +/- 0.1 mU/L; P less than 0.01; Cluster program: 0.5 +/- 0.1 vs. 0.2 +/- 0.1 mU/L; P less than 0.05), whereas TSH pulse frequency during fasting was unchanged (Desade program: 8.4 +/- 0.9 vs. 9.8 +/- 0.8 pulses/24 h; Cluster program: 9.5 +/- 0.5 vs. 7.9 +/- 0.9 pulses/24 h). There was a highly significant correlation between the mean 24-h TSH concentration and the mean TSH pulse amplitude during both the control period and fasting. Although the decrease in TSH concentration during fasting was evident over 24 h, fasting especially decreased the absolute (1.3 +/- 0.3 vs. 0.4 +/- 0.1 mU/L, P less than 0.02) and the relative (101 +/- 18% vs. 40 +/- 14%; P less than 0.02) nocturnal TSH surge (mean TSH 0000-0400 h vs. mean TSH 1500-1900 h). The decreased nocturnal TSH surge during fasting was associated with a significantly decreased TSH pulse amplitude, but with an unaltered number of TSH pulses between 2000-0400 h. In conclusion, fasting decreases 24-h TSH secretion and the nocturnal TSH surge in the absence of a change in plasma T4 concentration. This is associated with a decreased TSH pulse amplitude, whereas TSH pulse frequency remains unchanged.
在8名健康受试者（4名男性和4名处于卵泡期的女性）中研究了禁食对昼夜节律性和脉冲性促甲状腺激素（TSH）分泌的影响。每位受试者接受两次研究，一次在正常进食的24小时期间，另一次在60小时禁食的最后24小时期间。在24小时内每10分钟采集一次血液，通过灵敏的免疫放射分析测定TSH。禁食导致血浆三碘甲状腺原氨酸（T3）降低[1.73±0.06 vs. 1.36±0.04 nmol/L；P<0.01（均值±标准误），对照期vs.禁食期]和甲状腺球蛋白降低（52±8 vs. 35±7 pmol/L；P<0.001），以及血浆反三碘甲状腺原氨酸（rT3）升高（0.30±0.06 vs. 0.44±0.09 nmol/L；P<0.02）。两个时期的血浆甲状腺素（T4）、甲状腺激素结合指数和游离T4无统计学差异。禁食期间24小时血浆TSH平均浓度低于对照期（2.0±0.3 vs. 1.0±0.2 mU/L；P<0.005）。这与禁食期间TSH脉冲平均幅度降低有关（德萨德程序：0.6±0.1 vs. 0.3±0.1 mU/L；P<0.01；聚类程序：0.5±0.1 vs. 0.2±0.1 mU/L；P<0.05），而禁食期间TSH脉冲频率未改变（德萨德程序：8.4±0.9 vs. 9.8±0.8次脉冲/24小时；聚类程序：9.5±0.5 vs. 7.9±0.9次脉冲/24小时）。对照期和禁食期24小时TSH平均浓度与TSH脉冲平均幅度之间存在高度显著相关性。尽管禁食期间TSH浓度在24小时内明显降低，但禁食尤其降低了夜间TSH的绝对升高幅度（1.3±0.3 vs. 0.4±0.1 mU/L，P<0.02）和相对升高幅度（101±18% vs. 40±14%；P<0.02）（00:00 - 04:00时平均TSH值vs. 15:00 - 19:00时平均TSH值）。禁食期间夜间TSH升高幅度降低与TSH脉冲幅度显著降低有关，但20:00 - 04:00时TSH脉冲数量未改变。总之，在血浆T4浓度无变化的情况下，禁食会降低24小时TSH分泌和夜间TSH升高幅度。这与TSH脉冲幅度降低有关，而TSH脉冲频率保持不变。
