The metabolic clearance rate, blood production, interconversion and transplacental passage of cortisol and cortisone in pregnancy near term

Inese Z. Beitins, Francis Bayard, Isadore G. Ances, Avinoam Kowarski, Claude J. Migeon

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Abstract

A constant infusion of 14C-cortisol and3H-cortisone for 4 hr was given to six pregnant women, at term, at the time of elective cesarean section. Radioactive and nonradioactive cortisol (F) and cortisone (E) concentrations were determined in maternal and cord plasma at the time when the concentration of the radioactive steroids had reached a plateau. Metabolic clearance rates (MCR), plasma levels of endogenous F and E, blood production rates (BP), conversion ratios (Cr), and transfer constants ([ρ]BB values) were calculated and compared with those obtained in eight nonpregnant women, half of whom took contraceptive medication (subjects taking “the pill”) and half of whom did not (control subjects). The MCR (F) of women near term, control subjects, and women receiving contraceptive treatment were (mean ± SD) 133 ± 47, 141 ± 37, and 62 ± 24 liters/24 hr, respectively. The latter was significantly lower than the other two. The MCR (E) were similar in all three groups of subjects and 4-7 times greater than MCR (F). The ratio of the endogenous F/E for control subjects was significantly lower (4.8 ± 0.6) than that for women on the pill (9.0 ± 1.6) or for pregnant women (7.5 ± 1.7). In contrast to their mothers, the neonates had an F/E ratio of 0.85 ± 0.34 with a mother/cord ratio for F of 4.9 ± 2.5 and for E of 0.50 ± 0.15. In eight fetuses of 3-6 months of gestational age, plasma concentrations of F (2.1 ± μg/100 ml) and E (4.7 ± 3.3 μg/100 ml) were lower than those of six neonates (6.3 db 2.9 for F and 7.2 ± 1.2 /μ/100 ml for E). For control subjects, the CrF→E was significantly higher and the CrE→F significantly lower than these ratios for pregnant women and for women on contraceptive medication. From the values of BP (F) for each subject and the corresponding transfer constant (formula presented) it was estimated that all the BP (E) for the subjects studied arose from BP (F), which suggested that, within the limits of error of the methods used, there was no E secretion.

Original languageEnglish (US)
Pages (from-to)509-519
Number of pages11
JournalPediatric research
Volume7
Issue number5
DOIs
StatePublished - May 1973

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ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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