Hormones

Abstract

Because the more definitely biochemical advances in the field of hormones are very nearly limited to those of the steroid type together with the limited space available for reviewing a very extensive litera ture, I have taken advantage of the editors' liberal policy and have limited this review to the biochemistry of the steroid hormones. ESTROGENSDistribution and forms of estrogens.-Although all of the estro gen activity in cow and hog ovaries is considered to be in the free form, only 50 to 75 per cent is free in the horse ovary or its follicular fluid (1). During pregnancy 50 to 75 per cent of the blood estrogens in women are in the free form (2). The best method of hydrolysis of the conjugated forms of estrogens in pregnancy urine is still a prob lem. One g.roup recommends boiling the pregnancy urine for ten minutes with 15 per cent concentrated hydrochloric added. Longer heating results in serious loss of estrogens (3). Others recommend that the urine from pregnant mares be allowed to stand at pH 0.4 to 0.6 at room temperature for at least four weeks (4). The writer, in studies on urine from normal men and nonpregnant women, has obtained the highest yield of estrogens by boiling the urine previously acidified to pH 1 to 1.2 with hydrochloric acid for fifteen minutes.Longer boiling at this pH also causes destruction of estrogens. The gradual increase in the urinary excretion of estrogens in women to a peak of 80,000 rat units near the termination has been confirmed, but in one case of toxemia of pregnancy, the excretion was subnormal.