Peptide histidine isoleucine- and vasoactive intestinal polypeptide-like immunoreactivity coexist in rat hypophysial portal blood.
Plasma immunoreactive peptide histidine isoleucine (PHI) and vasoactive intestinal polypeptide (VIP) levels were measured by specific radioimmunoassays in urethane-anesthetized rats. Basal levels of plasma PHI-like immunoreactivity (PHI-LI) in the hypophysial portal blood were 414 +/- 180 pmol/l (means +/- S.E.), about 7 times higher than in the peripheral blood. VIP-like immunoreactivity (VIP-LI) was also high in the portal blood (399 +/- 139 pmol/l). The correlation coefficient between PHI-LI and VIP-LI was 0.76. These findings suggest that PHI and VIP are co-released from the median eminence into the hypophysial portal blood in rats.
D000818:Animals; D008297:Male; D008473:Median Eminence / Q000378:metabolism; D010451:Peptide PHI; D010455:Peptides / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000097:blood*
D010451:Peptide PHI; D010455:Peptides; D014660:Vasoactive Intestinal Peptide