Lean J M, Chow J W, Chambers T J
Department of Histopathology, St George's Hospital Medical School, London, UK.
J Endocrinol. 1994 Jul;142(1):119-25. doi: 10.1677/joe.0.1420119.
We have recently found that administration of oestradiol-17 beta (OE2) to rats stimulates trabecular bone formation. It is not known, however, whether oestrogen has a similar action on bone formation rate under physiological circumstances. Oestrogen is known to suppress bone resorption, and oestrogen-deficient states in the rat, as in humans, are associated with an increase in bone resorption that entrains an increase in bone formation. To see if the latter masks a relative reduction in bone formation, due to oestrogen deficiency, we measured bone formation very early after ovariectomy, before the resorption-induced increase in bone formation becomes established. To do this, rats were administered fluorochrome labels before and after ovariectomy, spaced at weekly intervals in the first, and 3-day intervals in the second experiment. In both experiments there was a decrease in indices of bone formation in the labelling interval immediately following ovariectomy such that, using the shorter fluorochrome intervals, the mineral apposition rate fell to 69%, the double-labelled surface to 45%, and the bone formation rate to 36% of sham-ovariectomized levels. The reduction was not sustained in the subsequent label intervals, presumably masked by the increase in bone formation attributable to increased resorption. These results suggest that if bone formation is assessed before this resorption-entrained increase in bone formation occurs, oestrogen deficiency is associated with a reduction in dynamic indices of bone formation.(ABSTRACT TRUNCATED AT 250 WORDS)
我们最近发现，给大鼠注射17β-雌二醇（OE2）可刺激小梁骨形成。然而，在生理情况下雌激素对骨形成率是否有类似作用尚不清楚。已知雌激素可抑制骨吸收，与人类一样，大鼠雌激素缺乏状态与骨吸收增加有关，而骨吸收增加会带动骨形成增加。为了探究后者是否掩盖了因雌激素缺乏导致的骨形成相对减少，我们在卵巢切除术后极早期测量骨形成，此时吸收诱导的骨形成增加尚未确立。为此，在卵巢切除术前和术后给大鼠注射荧光染料标记，在第一个实验中每隔一周注射一次，在第二个实验中每隔三天注射一次。在两个实验中，卵巢切除术后紧接着的标记间隔内骨形成指标均下降，因此，使用较短的荧光染料间隔时，矿物质沉积率降至假手术卵巢切除水平的69%，双标记表面降至45%，骨形成率降至36%。在随后的标记间隔中，这种降低并未持续，可能被因吸收增加导致的骨形成增加所掩盖。这些结果表明，如果在这种吸收带动的骨形成增加出现之前评估骨形成，雌激素缺乏与骨形成动态指标降低有关。（摘要截短于250字）
