Extreme stability of Tyr-MIF-1 in CSF.
Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2), an endogenous brain peptide, was incubated at 37 degrees C in cerebrospinal fluid (CSF) from rats and the amount remaining in intact from determined by high performance liquid chromatography (HPLC). By 3 min, a time at which Tyr-MIF-1 had been considerably degraded by rat plasma, essentially no degradation of the tetrapeptide had occurred in CSF. Tyr-MIF-1 persisted in mainly intact form for the 8 days tested, with a calculated half-time degradation of 11.4 days. The simultaneous addition to CSF of equal amounts of Tyr-MIF-1 tritiated on the Tyr and Tyr-MIF-1 tritiated on the Pro facilitated determination of whether Tyr-MIF-1 serves as a precursor of MIF-1 (Pro-Leu-Gly-NH2) in CSF. This possibility was excluded by the findings that the primary metabolite was Tyr-Pro, with minimal and equal amounts of the free amino acids Pro and Tyr being formed, but no MIF-1. The results show the extreme stability of Tyr-MIF-1 in CSF and are consistent with a role for this peptide in the CNS.
Kastin
A J
AJ
VA Medical Center, New Orleans, LA.
Banks
W A
WA
Hahn
K
K
Zadina
J E
JE
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D007456:Iodine Isotopes; D009075:MSH Release-Inhibiting Hormone / Q000031:analogs & derivatives* / Q000134:cerebrospinal fluid; D008297:Male; D008969:Molecular Sequence Data; D051381:Rats; D017207:Rats, Sprague-Dawley
D007456:Iodine Isotopes; C036930:tyrosyl-prolyl-leucyl-glycinamide; D009075:MSH Release-Inhibiting Hormone