Wang D Y, Sturzaker H E, Kwa H G, Verhofstad F, Hayward J L, Bulbrook R D
Int J Cancer. 1984 May 15;33(5):629-32. doi: 10.1002/ijc.2910330513.
The amount of prolactin has been determined in serial blood samples taken over 24 h from 20 pre- and 9 postmenopausal women volunteers. All women had a large increase in prolactin at night (24.00 h-03.00 h). A much smaller rise in prolactin occurred in the evening (18.00 h-20.00 h) which was just significantly different (p less than 0.05) from levels found in the afternoon. Prolactin concentrations at any given time in the 29 women were linearly correlated with corresponding levels in either of the adjacent time intervals. This correlation was highly significant (p less than 0.001) throughout 24 h, implying that a woman with a relatively high (or low) blood prolactin in the afternoon would have a similarly high (or low) concentration in the evening or at night. Premenopausal women had higher amounts of prolactin than postmenopausal volunteers throughout the day. Parity was found to be inversely related to prolactin levels in pre- and postmenopausal women; this effect was especially marked in the night peak of prolactin. In postmenopausal women an average of 33 years had elapsed since the birth of the last child, which implies that childbirth has a life-long effect on reducing prolactin levels. Thus the protective effect of early child-bearing and multiparity against developing breast cancer could be at least partly explained by these effects on serum prolactin levels.
对20名绝经前和9名绝经后女性志愿者在24小时内采集的系列血样中的催乳素含量进行了测定。所有女性在夜间（24:00至03:00）催乳素水平均大幅升高。傍晚（18:00至20:00）催乳素水平也有升高，但幅度小得多，与下午的水平相比有显著差异（p<0.05）。29名女性在任何给定时间的催乳素浓度与相邻两个时间间隔中任意一个的相应水平呈线性相关。这种相关性在24小时内都非常显著（p<0.001），这意味着下午催乳素水平相对较高（或较低）的女性在傍晚或夜间也会有类似的高（或低）浓度。绝经前女性全天的催乳素含量高于绝经后志愿者。经产状况与绝经前和绝经后女性的催乳素水平呈负相关；这种影响在催乳素的夜间峰值时尤为明显。绝经后女性自最后一个孩子出生以来平均已过去33年，这意味着分娩对降低催乳素水平有终生影响。因此，早育和多产对预防乳腺癌的保护作用至少可以部分地用其对血清催乳素水平的这些影响来解释。
