Splanchnic and renal vasoconstrictor and metabolic responses to neuropeptide Y in resting and exercising man.

The local clearance of neuropeptide Y (NPY) and whether NPY influences splanchnic and renal metabolism in man have not been investigated previously. The influence of NPY on splanchnic and renal blood flows at physiologically elevated levels has also not been investigated. The effects of a 40-min constant NPY infusion (3 pmol kg-1 min-1) at rest and during 130 min of exercise (50% of VO2max) were studied in six healthy subjects and compared with resting and exercising subjects receiving no NPY.

Splanchnic and renal vasoconstriction during neuropeptide Y infusion in healthy humans.

To assess whether neuropeptide Y (NPY) causes vasoconstriction in human splanchnic and renal tissues, six healthy subjects were given NPY intravenously in the basal resting state for 15 min. The NPY dose of 10, 25, and 50 pmol kg-1 min-1 was increased every 5 min. The infusion was accompanied by elevated arterial plasma levels of NPY-like immunoreactivity (Li) which were 15, 40, and 85 times higher than the basal value.

Long-lasting vasoconstriction and efficient regional extraction of endothelin-1 in human splanchnic and renal tissues.

Six healthy subjects were given endothelin-1, intravenously in a dose of 4 pmol.kg-1.min-1 for 20 min.

Elevated plasma levels of endothelin in patients with sepsis syndrome.

The levels of the recently isolated endothelial-derived peptide, endothelin, which has potent vasoconstrictor properties, were analyzed by radioimmunoassay in plasma from six patients with sepsis syndrome. For comparison endothelin levels were also measured in plasma from ten healthy volunteers. In the septic group plasma endothelin-like immunoreactivity was five-fold higher (11.

Evidence for release of endothelin-1 in pigs and humans.

The release and pharmacokinetics of endothelin-1 (ET-1) in plasma were studied in pigs and humans in vivo. Between 50-90% of plasma ET-1-like immunoreactivity (LI) was cleared by the pig and human kidney, splanchnic circulation, and skeletal muscle. The precursor big ET-1 was only cleared to a moderate extent (34%) by the kidney with progressive formation of ET-1-LI in the pig.