The Effects of Oestradiol on the Skeletal Muscle and Liver of the Rat

Abstract

The chemical composition of the liver and skeletal muscle in rats which had been treated with 1\m=.\0\g=m\g. oestradiol has been investigated. The water and electrolyte content, creatine and creatinine phosphorus fractions and total nucleoproteins were studied. The changes in the water content are reciprocal to those already described for the uterus. The creatine and creatinine content and the total nucleic acid do not change significantly. There is an increase of the acid-soluble phosphorus in the first phase of the water increase in skeletal muscle which is related to some of the changes of intracellular potassium. In the liver there is an increase of the total water content between 28 and 36 hr. after injection, which is also associated with changes of acid-soluble phosphorus and cell electrolytes.Zuckerman, Palmer & Hanson [1950] showed that the changes in skeletal muscle (gastrocnemius and triceps) were, in the main, reciprocal to those in the uterus, so far as the water content was concerned. The water content reached a peak between 18 and 24 hr., and at 54 hr. after the injection of oestrogen. Little appears to be known about the effects of this treatment on the water and electrolyte balance in the liver.The changes induced by oestradiol-17 (ß) in the water and electrolyte composition of the rat uterus have been reported in an earlier paper [Cole, 1950 c]. The investiga¬ tion has now been extended to skeletal muscle and liver, without altering the experimental procedure. MATERIAL AND METHODSMature female rats were spayed under ether anaesthesia 3 weeks before use and were always allowed free access to food and water. The animals were injected with 1-0 µg. oestradiol-17 (ß) subcutaneously and were killed at intervals of 0, 8, 18, 24, 36, 54 and 72 hr. after the injection. Determinations of the intravascular space, water and electrolyte distribution, creatine and creatinine, phosphate fractions and total nucleic acids were made after each of these intervals in accordance with the methods previously described [Cole, 1950a-c]. Six animals were used for each determination, and the mean for any determination shown in the table is therefore derived from six experimental values. RESULTSThe results are given in Tables 1-4. The differences between the groups of rats killed at different times are calculated with reference to the control group at zero time. The significance of the differences have been estimated by means of the 't' test. The quantity represented by V, the relative cell volume in Conway's terminology [Boyle & Con way, 1941], is also calculated with reference to the control series [Conway & Hingerty, 1946; Cole, 1950a, 6].

The effects of stilboestrol on the renal activity of conscious dogs

“…In humans, too, neither castration nor 237 238 PAMELA DANCE, SYBIL LLOYD AND MARY PICKFORD the post-menopausal state altered the response to oestradiol (Dignam et al 1956). The time after treatment when signs of water and electrolyte retention were maximal in dogs, namely 18-48 hr, is similar to the period in rats during which there is a marked increase in the water content of the tissues (Zuckermann, Palmer & Hanson, 1950;Cole, 1952). In rats the tissue water returned to normal after 48 hr.…”

Human Body Composition

“…They do of course affect uterine size. In acute experiments on castrated female rats, Cole (1952) found that estradiol injections caused an increase in ECF volume in both muscle and liver, but a decrease in ICF volume. While there are no extant data on body composition, castrated girls tend to grow tall, and girls who have a late menarche tend to be taller than their postmenarchal age peers.…”

“…In acute experiments on castrated female rats Cole (1952) found that estradiol produced an increase in ECF volume and a decrease in intracellular fluid (ICF) volume of both muscle and liver. Preedy and Aitken (1956) gave estradiol to human subjects.…”

Some in vitro observations on water, sodium and potassium metabolism in the oestrous rat uterus

“…Calcium may thus have at least two actions in the rat uterus: the maintenance of (1) the idiomolar value and (2) the integrity of the cell membrane and of the 'sodium pump'. P. J. BENTLEY AND ALISON HOLLAND With regard to the first effect the rat uterus is known to have a larger and more labile idiomolar value than skeletal muscle (Cole, 1950(Cole, , 1951 and this is affected by oestradiol (Cole, 1950). Calcium is known to have a 'stabilizing' effect on proteins (Gurd & Wilcox, 1956), and as calcium is bound to intracellular structures forming bridges between anionic groups (Haurowitz, 1956) a loss of calcium may result in a break-down of organic molecules and increased idiomolar value.…”