Endocrine Abstracts

Introduction

The secretion of multiple hormones occurs in both a circadian and an ultradian manner. Both animal and human studies have shown that cortisol has an ultradian rhythm. Variations in ultradian cortisol secretion may explain inter-individual variation in the stress response.

Objective

We have developed an automated blood sampling system (ABS) that allows undisturbed sampling of blood, thus reducing stress and allowing measurements during sleep.

Methods

After local ethical approval, preliminary studies were conducted in healthy volunteers. The ABS is trolley based allowing subjects to move. An intravenous cannula is sited and connected through long microbore sampling tubing to a programmable pump. This collects blood under the control of a computer. A separate pump infuses saline to flush the cannula and collection line. Specific software allows programming of the timing and frequency of blood sampling.

Results

We have demonstrated that we can safely carry out automated undisturbed blood sampling.

Conclusion

The ABS system has great potential for future studies of hormone pulsatility and their relationship to physiological and pathological changes.