MAGNESIUM AND CALCIUM GRADIENTS IN THE PREMENOPAUSAL AND POSTMENOPAUSAL HUMAN MYOMETRIUM

Magnesium and calcium, as well as sodium and postassium, have an important influence on the physiology of contraction of the uterus. The ionic concentrations in the pre- and postmenopausal myometrium were examined. We assumed, that there are differences in the electrolytic contents because of the different functions of the corpus, isthmic part and cervix uteri during pregnancy and througout labour. Small tissue samples from 37 premenopausal and 20 postmenopausal patients, who underwent an operation with different indications, were dissected after hysterectomy. Magnesium and calcium levels were determined by atomic absorption spectrophotometry and postassium and sodium by emission spectrometry in the wet tissue. In both groups, we found significant differences of the electrolytic contents of the myometrium. In the premenopausal uteri, the magnesium levels decrease significantly (p < 0.001) from the corpus (xBAR = 4.14 mmol/kg) to the cervix (xBAR = 2.14 mmol / kg). The same scenario can be observed for the potassium levels (Corpus xBAR = 56.2 mmol/kg and cervix xBAR = 25.4 mmol/kg). In contrary, the calcium levels (Corpus xBAR = 1.60 mmol/kg and cervix xBAR = 2.26 mmol/kg) and sodium levels (Corpus xBAR = 69.3 mmol/kg and cervix xBAR = 93.0 mmol/kg) increase significantly (p < 0.001). In the postmenopausal group, we found slightly elevated concentrations of magnesium, sodium and potassium. Only the calcium content of the corpus uteri rises up to three times about 20 years after the menopause (from xBAR = 1.60 mmol/kg) (p < 0.001). The electrolytic contents in the myometrium were shown to be different in the corpus, isthmus and cervix uteri. We hypothesise, that in the human myometrium the high magnesium levels and the low calcium levels in the corpus uteri, could be explained by the high level of myometrial cells and by the ability to contract. The low magnesium and high calcium levels in the cervix uteri could be explained by the ability to dilate and a low content of smooth muscle cells in the interstitium. This distribution corresponds with the physiological functions.