Endocrine Abstracts

The synthesis and metabolism of bile acids and steroid hormones are conflicted at several levels. We investigated potential interactions using a feeding paradigm to stimulate bile acid secretion and salivary steroid measurements to monitor post-prandial changes.

The study followed a randomised cross over design; both cortisol and cortisone were measured by specific ELISAs to assess effects on 11 beta-hydroxysteroid dehydrogenase activity (11βHSD). At midday, groups of male and female volunteers (n=8 each, aged 18–26 years; BMI=22.77±3.58 kg/m² and systolic/diastolic BP were 122.9±7.7/70.5±8.1 mmHg) were fed isocaloric low carbohydrate/high fat or high carbohydrate/low fat meals with uniform content of protein. On a third occasion samples were collected with ad libitum feeding. On each test day, saliva was obtained immediately before feeding, 15, 30, and 90 min later and also early that morning and later in the evening. Urine samples over 24 h were collected.

Salivary cortisol and cortisone values showed expected diurnal variation. Female compared to male values were similar for cortisol, lower for cortisone and urinary bile acids levels and higher for cortisol:cortisone ratios (P<0.005). Post-prandial cortisol increases were more marked for females after a high fat meal than a low fat meal whereas in males, postprandial cortisone was greater after a high fat than a low fat meal (P<0.05). High and low fat meals did not affect urinary bile acid levels but, in males, urinary levels of bile acids correlated positively with the salivary cortisol:cortisone (r=0.64; P<0.001). Neither cortisol nor cortisone correlated with bile acid levels in females or males.

Salivary steroid measurements are a useful non-invasive method of assessing effects of food intake. We observed sex-specific effects of high and low fat diets on cortisol and cortisone levels. Contemporaneous measurements of circulating bile acids are needed to assess whether food-induced changes in bile secretion influence post-prandial steroid levels. Sex-specific differences in bile metabolism may affect 11 βHSD1 activity.