1+2/2011 - Společnost pro pojivové tkáně

submits results from their own research (17). At least all these measurements are carriedout by the same measurement technique and are comparable. Therefore, we set standardOPG and RANKL levels according to data that are there referred to: [RANKL stand ] = 0.84pmol/l = 55 . 0.84 pg/ml = 46.2 pg/ml and [OPG stand ] = 1.8 pmol/l = 20 . 1.8 pg/ml = 36pg/ml and in serum (Kudlacek et al, 2003), where the knowledge of molecular weightsMW RANKL = 55 . 10 3 , MW OPG = 20 . 10 3 was used (13, 44). OPG serum levels found in humanare 12–138 pg/ml = 0.6–6.9 pmol/l and RANKL serum levels are 0–250 pg/ml = 0–4.55 pmol/lwith standard values of 0.84 pmol/l for RANKL and 1.8 pmol/l for OPG, respectively.EstradiolEttinger et al. describe standard values of estradiol in humans 40–60 pg/ml (18). Further,this study also asserts that there is a significant correlation between estradiol serum levelsand bone density which will be later used. The value 50 pg/ml was used as a standard serumlevel.PTHStandard in vivo serum level of PTH in humans were again assessed from literature.Khosla et al. state that PTH serum levels in humans are in 0–6 pmol/l (28). Further, Jorde etal. mentions that standard in vivo PTH level in non-smokers is 3.6 pmol/l = 33.84 pg/ml (25),where the fact that MW PTH = 9400 was used (Potts, 2005). Now, we need to find a study thatwould capture PTH effects on bone remodelling. Charopoulos et al. studied effects of primaryhyperparathyroidism in both calcemic and non-calcemic groups (10). They mentionnormal PTH levels to be 37.13 pg/ml with typical range 25–45 pg/ml and these data will beused. Calcitonin protects against calcium loss from skeleton during periods of calcium mobilization,such as pregnancy and, especially, lactation. In other words, calcitonin counteractsPTH. Due to its activity it can be included and consecutively, PTH levels adjusted.NONitric oxide is a small molecule that can freely diffuse across cell membrane withoutany use of channels (and thus without any control from cell). Probably this easy access isreason for its signalling function. Also, because there is no need of passive or even activetransportation across membrane it provides very fast communications. From the mentionednature of signalling molecule NO, it is evident that it plays role in many processesin body, and concretely, it influences bone remodelling. It is a very reactive agent (halflifeis 1 second) and thus it has a very localised effects; after menopause, the circulatingNO is significantly lower than before. Wimalawansa et al. studied the effect of NO donor(concretely nitroglycerin) treatment on body mass density (BMD) change in rats in a dosedependet manner. Further, they performed a pilot study of NO effects on humans (surgicallyinduced menopause women), which had promising results: nitroglycerin had similarmaintenance effects as estrogen on BMD (58). However, NO seems to have a biphasicPOHYBOVÉ ÚSTROJÍ, ročník 18, 2011, č. 1+2 31