Aims: 

PACAP is a neuropeptide originally isolated from the hypothalamus but later shown in the nervous system and in most peripheral organs. PACAP plays a role in numerous physiological functions. The structure of PACAP is the same in all mammalian species, including humans. Our aim is to study the presence and concentration of PACAP in different biological fluids.

Methods: 

We used radioimmunoassay and mass spectrometry measurements.

Results: 

The level of PACAP in the plasma did not show significant gender- or age-dependence. The presence of PACAP in several other fluids was revealed. Milk contained PACAP at concentrations 5–20 times higher than in the plasma. All follicular fluid samples contained PACAP, while amniotic fluid and vaginal smear did not. Spermatic fluid contained PACAP only in few samples, its clinical significance awaits further investigation. We also measured PACAP levels in ophthalmological samples: the tear fluid contained PACAP in all cases, while we could not detect the peptide in vitreous humor. Cerebrospinal fluid only contained PACAP under pathological conditions, as in patients with severe head trauma. All other biological samples were negative for the presence of PACAP, like saliva or sweat. After showing the presence of PACAP in body fluids, our future goal is to find correlations between PACAP levels and pathological conditions and use PACAP as a biomarker. The level of PACAP significantly changed in blood samples obtained from certain patients, like preeclampsia, where levels were around a thousand times higher. In patients with severe head trauma, PACAP levels showed a peak 24–48 hours in the serum and in the cerebrospinal fluid.

Conclusion: 

The measurement of PACAP is standardized and the distribution and concentration range is established in biological fluids. Further investigation is needed to draw correlations between PACAP levels and pathological conditions.

Support: 

OTKAF67830, K72592, CNK78480, T73044, Bolyai, PTE AOK Research Grant