The hydrocortisone production in late pregnancy

The effect of gestational parity on FEV1 in a group of healthy volunteer women

In the past, studies utilizing within-subject comparisons of small groups of pregnant women showed that forced expiratory volume in 1 s (FEV1) remained essentially unchanged during pregnancy. However, one of the findings from an epidemiological study was that women with greater number of children experienced a faster decline of FEV1. The aim of this study was to examine the effect of parity on FEV1 in a group of healthy volunteer women. To this end, cross-sectional multiple regression analyses of data from 397 healthy women participants in the Baltimore Longitudinal Study of Aging (BLSA) with a mean (range) age of 47.7 (18-92) years were performed. Similar analyses were done using the younger (50 years or less) and the older (> 50 years) subgroups. After controlling for age, height, weight, and smoking, parity as a dichotomous variable was associated with a higher FEV1 in women of child-bearing age (0.139 1; P = 0.02) but not in the older women. There was a modest link with the number of children (P = 0.05), with the first child possibly having the greatest effect on FEV1. We could not account for the effect of parity on FEV1 by the educational level, occupation, health status of the women, or by the presence of a cohort effect. Thus the nulliparous state is associated with lower FEV1 in this group of healthy adult women of child-bearing age.

CLINICAL VALUE OF THE CORTISOL SECRETION RATE

The isotopic estimation of the cortisol secretion rate in man is now an accepted and reliable method of assaying adrenal cortical function.Seven years' experience with its clinical use is reviewed and some practical aspects of technique are considered. The mean normal resting cortisol secretion rate is 16.2 +/- 5.7 mg. daily. In all of 14 cases of hypopituitarism studied secretion has been less than 2.1 mg. daily. In all of 26 cases of established Cushing's syndrome, the cortisol secretion was above 36 mg. The method can be used to follow day-by-day changes in adrenal cortisol activity and examples of such use are given. The urinary 17-ketogenic steroid excretion frequently gives results which conflict with secretion rate estimates, and can lead to erroneous clinical conclusions.

Adrenocortical failure in diabetic pregnancy

A Caucasian class F diabetic developed features suggestive of adrenocortical insufficiency during the second half of pregnancy. Serial biochemical and hormonal studies confirmed a diagnosis of progressive primary adrenal failure. Replacement therapy was introduced at 31 weeks' gestation and the pregnancy ended successfully 6 weeks later. Addison's disease is another autoimmune disorder that may occur in association with diabetic pregnancy.

Ventilatory function in pregancy

In this investigation 60 pregnant patients underwent serial estimation of forced vital capacity (FVC) and forced expiratory volume (FEV1) throughout pregnancy and after delivery. No significant change occurred in the group mean figures of these measurements of ventilatory function. When patients were divided into those who were non-smokers and those who smoked more than 10 cigarettes daily it appeared that both FVC and FEV1 during the last 8 weeks of pregnancy were slightly reduced in the smokers.

Previous studies on the effects of pregnancy upon ventilatory function are reviewed. In this report individual patients had greater variation in both amount and direction of serial recordings than was shown by control subjects. This individual variation may have been responsible for the conflict in some earlier reports which studied smaller numbers of patients.

It is suggested that the maintenance of FEV1 and FVC during pregnancy in spite of increasing uterine size and increasing blood volume is the result of hormonal action upon the brain stem, chest wall and lung.

Increased exposure of tissues to cortisol in late pregnancy

In late normal pregnancy the mean day-night variation of non-protein-bound cortisol in plasma was found to be reduced to 52%, from a mean of 82% in non-pregnant subjects. Levels of unbound cortisol at midnight and at 9 a.m. in late pregnancy were raised above the non-pregnant normal. These levels led to increased urinary free cortisol excretion in pregnancy.This "tissue exposure" in late pregnancy is two to three times normal, as judged by both plasma unbound and urinary free cortisol measurements. The well-known increase in urinary free cortisol excretion in pregnancy is explained by the reduced day-night rhythm.

The effect of cortisol on the haematocrit values and serum electrolytes of the adult and foetal rat

1. The serum sodium, potassium and chloride levels of the non-pregnant rat, pregnant rat and foetus were estimated under normal circumstances and following the administration of 3 mg/kg cortisol to the non-pregnant and pregnant rat.2. Normally, the electrolytes and haematocrit value of the non-pregnant rat and the electrolytes of the foetus were higher than those occurring in the pregnant rat.3. After treatment with cortisol, the sodium, potassium and chloride content of the serum, and the haematocrit value of the non-pregnant rat dropped significantly. There was no change in these values in the pregnant animals, but the foetus showed a significant decrease in sodium, potassium and chloride levels after maternal treatment.