Chelsea
Department of Biochemical Endocrinology, Hospital for Women, Dovehouse Street, London S.W.3, and the Institute of Obstetrics and Gynaecology,
University
of London, London S.W.3
PLASMA 20\g=a\-DIHYDROPROGESTERONE, PROGESTERONE AND 17-HYDROXYPROGESTERONE IN NORMAL HUMAN PREGNANCY
By Emma Florensa, Robert Harrison, Michael and Ezat Youssefnejadian
Johnson
ABSTRACT The
peripheral plasma
20\g=a\-dihydroprogesterone (20\g=a\-DHP),
levels of
progesterone (P) and 17-hydroxyprogesterone (17-OHP)
were
measured
in 440 samples during normal human pregnancy between weeks 4 and 41. The levels of 20\g=a\-DHP in plasma from the 4th to the 6th week were between 6.0 and 6.6 ng/ml. From then until the 21st week the average plasma 20\g=a\-DHP concentrations remained at the same level between 4.0 and 6.3 ng/ml; they then rose significantly to and beyond term, levels reaching over 40 ng/ml. The range of mean plasma concentration of P during the first trimester of pregnancy fell to a nadir in the 9th week (170 ng/ml) then rose with increased gestation until the 39th week (190.4 ng/ml) followed by a slight and not significant drop. Single measurements of plasma 17-OHP from the 4th to the 6th week of pregnancy gave value between 2.8 and 3.6 ng/ml, but from the 7th week the mean plasma 17-OHP levels gradually declined, then from week 30 the 17-OHP concentration increased to reach a mean level of 7.63 ng/ml in the 41st week. The ratio P/20\g=a\-DHP increased from the 4th (3.5:1) to the 24th week (15.6:1) and then decreased from the 25th week (7.9:1) towards term
by radioimmuoassay techniques
(3.2:1).
The reduction of
progesterone (P)
dihydroprogesterone (20a-DHP).
at
to the formation of 20awhich is still biologically ac-
carbon-20, leads
This
compound
634
tive (though less than P) was found by Zander et al. (1958), in corpora lutea of the menstrual cycle and in the corpora lutea of pregnancy. Reduction of P at carbon-20 in the foetus and many human foetal tissues have been shown (Solomon 1966; Runnebaum et al. 1973). It has also been demonstrated that the high concentration of P in the umbilical vein is as¬ sociated with low levels of 20a-DHP (Runnebaum 8c Zander 1962; Zander 1961) whereas the situation is reversed in the umbilical artery. The reverse oxidation of 20a-DHP to P has been found to occur in the placenta and the myometrium (Zander 1963; Zander et al. 1969). Maeyama et al. (1973) found the rate of conversion of 20«-DHP to P in decidual tissue was higher in early rather than in late pregnancy. There are few data available on the concentration of 20a-DHP in human maternal peripheral blood during pregnancy (Short 1960; Greig et al. 1962; Rubin et al. 1970). These might provide additional information upon its func¬ tional role in pregnancy. The present work was therefore undertaken to study the 20«-DHP variations throughout gestation, relating this to P and 17-OHP simultaneously determined in the same aliquot of plasma.
MATERIAL AND METHODS
Peripheral venous blood was obtained good health who were between the 4th
from 420 pregnant women in apparently and 42nd week of gestation. Single samples were obtained at 4, 5, 6 and 42 weeks. Two samples at 41 and three at 23 weeks. In all other weeks, between 10 and 14 samples were estimated. The blood was col¬ lected into heparinzed tubes and immediately centrifuged to separate the plasma from cells. The plasma was stored at —15°C until assayed. 20a-DHP, P and 17-OHP were measured simultaneously in the same aliquot of plasma using radioimmunoassay techniques previously reported (Florensa 8c Sommerville 1973; Youssefnejadian et al. 1972a,o). Two-hundred «1 of plasma to which 2000 DPM of P and 2000 dpm of 17-OHP were added, extracted twice with 5 ml of ether, dried down and chromatographed on Sephadex LH 20, using a benzene:methanol (95:5) system. Two fractions were collected, one containing P and the other 17-OHP and 20«-DHP together. The fractions were dried down and made up in an appro¬ priate volume of acetone, from which aliquots were taken for radioimmunoassay and recovery measurements.
RESULTS
values and standard deviation of 20a-DHP, P and 17-OHP which simultaneously determined in 430 plasma samples from 420 pregnant women between the 4th and 42nd week of gestation are shown graphically in Fig. 1. Statistical analysis was carried out using Student's 2 sample ¿-test.
The
mean
were
635
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 WEEKS OF PREGNANCY
Mean ±
Fig-
L
plasma concentrations of 20a-dihydroprogesterone, progesterone, and 17hydroxyprogesterone, calculated from 440 determinations of each compound in 430 patients during normal pregnancy. (Based on 13 samples per week throughout pregnancy). sd
Single determinations of plasma 20«-DHP measured from 4th to 6th week of pregnancy gave levels between 6.0 and 6.6 ng/ml. From the 7th to the 21st week the mean plasma 20a-DHP concentration remained between 4.0 and 6.3 ng/ml. This plateau was followed by an increase in the mean plasma level of this hormone. Values obtained for weeks 20 and 41 showed a highly significant difference (P < 0.001). Three apparent peaks were noted, weeks 23, 25 and 29, respectively. These peaks may therefore indicate a trend of increase rather than reflect a time of increase of hormonal activity. The average plasma P concentration in the 7th and 8th week was lower than values obtained in previous weeks from single determinations. The fall was not statistically significant because of the small numbers of samples. The lowest value was reached at the 9th week with a mean concentration of 17.0 ng/ml then the P levels were continuously increasing to reach the highest con=
636
RATIO
P: 20«-DHP
157
10
U
6 8 10 12 14 16 16 20 22 24 26 28 30 32 34 36 38 40 42
WEEKS OF PREGNANCY
Fig. 2.
The average P/20a-DHP ratio
throughout
pregnancy.
60t RATIO
P: 17-OHP
50
404
304
204
-1-1-1-1-1-1-F-1-1-1-1-1-1-1-1-1-1-1 4
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 WEEKS OF
PREGNANCY
Fig. 3. The average P/17-OH P ratio 637
throughout
pregnancy.
centration in the 39th week (190.4 ng/ml). At and beyond term the mean P concentration fell. However this drop in value was not significant (for between 39 and 41 P
Department of Biochemical Endocrinology, Hospital for Women, Dovehouse Street, London S.W.3, and the Institute of Obstetrics and Gynaecology,
University
of London, London S.W.3
PLASMA 20\g=a\-DIHYDROPROGESTERONE, PROGESTERONE AND 17-HYDROXYPROGESTERONE IN NORMAL HUMAN PREGNANCY
By Emma Florensa, Robert Harrison, Michael and Ezat Youssefnejadian
Johnson
ABSTRACT The
peripheral plasma
20\g=a\-dihydroprogesterone (20\g=a\-DHP),
levels of
progesterone (P) and 17-hydroxyprogesterone (17-OHP)
were
measured
in 440 samples during normal human pregnancy between weeks 4 and 41. The levels of 20\g=a\-DHP in plasma from the 4th to the 6th week were between 6.0 and 6.6 ng/ml. From then until the 21st week the average plasma 20\g=a\-DHP concentrations remained at the same level between 4.0 and 6.3 ng/ml; they then rose significantly to and beyond term, levels reaching over 40 ng/ml. The range of mean plasma concentration of P during the first trimester of pregnancy fell to a nadir in the 9th week (170 ng/ml) then rose with increased gestation until the 39th week (190.4 ng/ml) followed by a slight and not significant drop. Single measurements of plasma 17-OHP from the 4th to the 6th week of pregnancy gave value between 2.8 and 3.6 ng/ml, but from the 7th week the mean plasma 17-OHP levels gradually declined, then from week 30 the 17-OHP concentration increased to reach a mean level of 7.63 ng/ml in the 41st week. The ratio P/20\g=a\-DHP increased from the 4th (3.5:1) to the 24th week (15.6:1) and then decreased from the 25th week (7.9:1) towards term
by radioimmuoassay techniques
(3.2:1).
The reduction of
progesterone (P)
dihydroprogesterone (20a-DHP).
at
to the formation of 20awhich is still biologically ac-
carbon-20, leads
This
compound
634
tive (though less than P) was found by Zander et al. (1958), in corpora lutea of the menstrual cycle and in the corpora lutea of pregnancy. Reduction of P at carbon-20 in the foetus and many human foetal tissues have been shown (Solomon 1966; Runnebaum et al. 1973). It has also been demonstrated that the high concentration of P in the umbilical vein is as¬ sociated with low levels of 20a-DHP (Runnebaum 8c Zander 1962; Zander 1961) whereas the situation is reversed in the umbilical artery. The reverse oxidation of 20a-DHP to P has been found to occur in the placenta and the myometrium (Zander 1963; Zander et al. 1969). Maeyama et al. (1973) found the rate of conversion of 20«-DHP to P in decidual tissue was higher in early rather than in late pregnancy. There are few data available on the concentration of 20a-DHP in human maternal peripheral blood during pregnancy (Short 1960; Greig et al. 1962; Rubin et al. 1970). These might provide additional information upon its func¬ tional role in pregnancy. The present work was therefore undertaken to study the 20«-DHP variations throughout gestation, relating this to P and 17-OHP simultaneously determined in the same aliquot of plasma.
MATERIAL AND METHODS
Peripheral venous blood was obtained good health who were between the 4th
from 420 pregnant women in apparently and 42nd week of gestation. Single samples were obtained at 4, 5, 6 and 42 weeks. Two samples at 41 and three at 23 weeks. In all other weeks, between 10 and 14 samples were estimated. The blood was col¬ lected into heparinzed tubes and immediately centrifuged to separate the plasma from cells. The plasma was stored at —15°C until assayed. 20a-DHP, P and 17-OHP were measured simultaneously in the same aliquot of plasma using radioimmunoassay techniques previously reported (Florensa 8c Sommerville 1973; Youssefnejadian et al. 1972a,o). Two-hundred «1 of plasma to which 2000 DPM of P and 2000 dpm of 17-OHP were added, extracted twice with 5 ml of ether, dried down and chromatographed on Sephadex LH 20, using a benzene:methanol (95:5) system. Two fractions were collected, one containing P and the other 17-OHP and 20«-DHP together. The fractions were dried down and made up in an appro¬ priate volume of acetone, from which aliquots were taken for radioimmunoassay and recovery measurements.
RESULTS
values and standard deviation of 20a-DHP, P and 17-OHP which simultaneously determined in 430 plasma samples from 420 pregnant women between the 4th and 42nd week of gestation are shown graphically in Fig. 1. Statistical analysis was carried out using Student's 2 sample ¿-test.
The
mean
were
635
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 WEEKS OF PREGNANCY
Mean ±
Fig-
L
plasma concentrations of 20a-dihydroprogesterone, progesterone, and 17hydroxyprogesterone, calculated from 440 determinations of each compound in 430 patients during normal pregnancy. (Based on 13 samples per week throughout pregnancy). sd
Single determinations of plasma 20«-DHP measured from 4th to 6th week of pregnancy gave levels between 6.0 and 6.6 ng/ml. From the 7th to the 21st week the mean plasma 20a-DHP concentration remained between 4.0 and 6.3 ng/ml. This plateau was followed by an increase in the mean plasma level of this hormone. Values obtained for weeks 20 and 41 showed a highly significant difference (P < 0.001). Three apparent peaks were noted, weeks 23, 25 and 29, respectively. These peaks may therefore indicate a trend of increase rather than reflect a time of increase of hormonal activity. The average plasma P concentration in the 7th and 8th week was lower than values obtained in previous weeks from single determinations. The fall was not statistically significant because of the small numbers of samples. The lowest value was reached at the 9th week with a mean concentration of 17.0 ng/ml then the P levels were continuously increasing to reach the highest con=
636
RATIO
P: 20«-DHP
157
10
U
6 8 10 12 14 16 16 20 22 24 26 28 30 32 34 36 38 40 42
WEEKS OF PREGNANCY
Fig. 2.
The average P/20a-DHP ratio
throughout
pregnancy.
60t RATIO
P: 17-OHP
50
404
304
204
-1-1-1-1-1-1-F-1-1-1-1-1-1-1-1-1-1-1 4
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 WEEKS OF
PREGNANCY
Fig. 3. The average P/17-OH P ratio 637
throughout
pregnancy.
centration in the 39th week (190.4 ng/ml). At and beyond term the mean P concentration fell. However this drop in value was not significant (for between 39 and 41 P
