Measurement of Cortisol, Cortisone, 11-Deoxycortisol and Corticosterone in Foetal Sheep Plasma During the Perinatal Period

Abstract

A method is described for the resolution and individual quantitation of cortisol, cortisone, 11-deoxycortisol and corticosterone in foetal sheep plasma. The steroids were extracted by solvent partition and separated by LH-20 Sephadex column chromatography. Radioimmunoassay was used for the measurement of 11-deoxycortisol and cortisone and competitive protein-binding for corticosterone and cortisol. The relative levels of these steroids in the plasma of chronically catheterized sheep foetuses from 12 days before birth to term and then in the newborn lamb until 2 days of age are recorded. Cortisol gradually increased from a basal concentration of between 0 - 5 and 3 - 0 mug/100 ml plasma between days 12 and 5 pre partum, and then rose rapidly to 10 mug/100 ml plasma during the last 5 days of pregnancy to reach a maximum during or just after birth. Two days post partum the levels had fallen to approximately 3 mug/100 ml plasma. The mean value for 11-deoxycortisol between days 8 and 3 pre partum was 0 - 4 mug/100 ml plasma and increased in the final days before delivery to 1 - 0 mug/100 ml. Corticosterone initially showed slightly higher levels (approximately 1 - 5 mug/100 ml) in the earlier period of investigation but then fell during the immediate pre-partum period to 0 - 8 mug/100 ml. Cortisone was not detected at any stage of the investigations. The relationship between levels of cortisol and 11-deoxycortisol in foetal plasma and myometrial contractility is shown. An increase in uterine activity was seen to occur at the time that cortisol levels were at their maximum. The 11-deoxycortisol values throughout this particular study remained low. The results are discussed in relation to recorded levels in the adult and to previous studies in vitro with regard to changing steroid biosynthetic enzyme activity.

Cortisone and Cortisol in Maternal and Fetal Blood and in Amniotic Fluid during the Final Ten Days of Gestation in the Rabbit

“…Smith (20) reported that the concentration of 11-dehydrocorticosterone ex ceeded that of corticosterone in the fetal rat over the last 5 days of gestation, but as these values were obtained by extracting whole fe tuses, little can be concluded as to the levels in blood. Surprisingly, Thomas et al (23) could not detect E in the plasma of fetal sheep despite the presence of substantial amounts of F. Nothing has been reported on the activity of 110-hydroxysteroid dehydrogenase in tissues of this species. In the fetal rabbit we have found that the F/E ratio in blood remains close to unity apart from at day 25, when it increases sharply; this is primarily due to a sixfold in crease in the concentration of F. The increase coincides, perhaps fortuitously, with an in crease in the concentration of E and F maternal plasma.…”

The development of the ovine fetal adrenal gland and its regulation

“…They then increase progressively up to G140 to enhance dramatically just before birth when they can reach 100 ng/mL (see fig 1 In the newborn lamb, they decrease within a few days to levels similar to those found in the adult (around 4 ng/mL) (Alexander et al, 1968;Brown et al, 1978;Magyar et al, 1980). From G100 on, fetal ovine plasma contains aldosterone, corticosterone, cortisol, 11-deoxycortisol and 11-deoxycorticosterone (Wintour et al, 1975;Thomas et al, 1976;Brown et al, 1978).…”

“…It is only from G120 onwards that the fetus starts producing cortisol (Wintour et al, 1980 (Cathiard et al, 1985). The cortisol/corticosterone ratio varies throughout gestation (Thomas et al, 1976;Brown et al, 1978 (Thomas et al, 1976;Brown et al, 1978;Wintour et al, 1995).…”

Adrenocorticotrophic Hormone in the Anterior and Neurointermediate Lobes of the Rat during the Perinatal Period: Polymorphism, Biological and Immunological Activities of ACTH

“…However, as the main hormones released by the fetus and newborn adrenals were reported to change during development in several species in cluding rat [25], sheep [46] and rabbit [19], one could speculate that these drastic changes in adrenal activity are related to the evolu tion of the different molecular forms of ACTH during the perinatal period. Such a hypothesis needs further investigations.…”