THE INFLUENCE OF OESTROGEN AND PROGESTERONE ON THE ELECTROLYTES OF THE HUMAN UTERUS

THE present report concerns the effects of oestrogen and of progesterone on the electrolytes of human myometrium. We have used the same methods as in previous studies (Hawkins and Nixon, 1958; Hawkins, Nixon and Whyley, 1958) to estimate extracellular and intracellular levels, employing chloride to measure the extracellular space. The assumptions involved and possible sources of error in this approach have been discussed in the previous reports. In the previous studies we investigated the changes in electrolyte composition which the myometrium of the human uterus undergoes in pregnancy. In particular, it was found that the myornetrial cells become progressively more hydrated as pregnancy proceeds and that the sodium content of the cells increases. In early pregnancy there is also an increase in extracellular water but by the end of pregnancy the myometrial composition alters in such a way that the normal proportion of extracellular water is restored. We also found that, when pregnancy is complicated by pre-eclampsia, a pathological increase of extracellular water and electrolytes occurs in late pregnancy, and myometrial intracellular sodium levels are increased. In order to deduce the mechanism of thc changes in myometrial electrolytes occurring in pregnancy and the possible causation of pathological modifications of electrolyte composition, it is necessary to know what are the effects of oestrogen and progesterone on uterine electrolytes. Such data as are available (Talbot, Lowry and Astwood, 1940; Horvath, 1954; Daniel and Daniel, 1957; Bitman el al., 1959) have been obtained with rats, rabbits and cats, and are partly contradictory. In order to interpret the changes in the electrolyte content of the human myometrium during pregnancy, it i s essential to obtain information, using the same methods, on the effects of oestrogen and progesterone on the human uterus. Electrolyte analyses of small biopsies of myometrium from non-pregnant and pregnant patients undergoing various operativc procedures after treatment with oestrogen or progesterone have therefore been undertaken. The doses of hormones which we have employed may well be small in relation to the endogenous production during pregnancy. Although only limited numbers of suitable cooperating patients were available, the results of this work gave information on the action of oestrogen and progesterone on myometrial electrolytes which is of assistance in the interpretation of the changes occurring in pregnancy.