Different patterns of central and peripheral beta EP, beta LPH and ACTH throughout life

The aim of the present study was to evaluate the relationship between central and peripheral concentrations of proopiocortin-related peptides in different periods of life. One hundred and eighty-nine plasma samples from normal subjects (18-87 years) obtained in basal conditions, and 20 cerebrospinal fluid (CSF) samples obtained by lumbar puncture from healthy volunteers (18-75 years) were studied. βLipotropin (βLPH), βendorphin (βEP) and ACTH were measured by specific RIA after silicic acid plasma extraction and gel chromatography (βLPH and βEP). No sex differences were found in the patterns of the three peptides either in the plasma or in CSF. In the plasma samples, both βLPH and βEP concentrations showed a pattern throughout life which was expressed by a paraboloid function with the lowest values found in young and old subjects and with peaks at 51.3 and 48.2 years, respectively. On the contrary, ACTH values failed to be represented by a significant linear or curvilinear regression and presented only a slight decrease in subjects over 75 years of age. CSF levels of βLPH were significantly lower in 45-76 year old subjects (18.8±12.6 fmol/ml, M±SD) than in 18-44 year old subjects (34.5±15.8; p<0.05), as were those of βEP (elderly: 41.2±19.7; young: 94.2±36.7; p<0.05), which showed a significantly linear inverse correlation with age (r=0.6062, p<0.01). These CSF samples did not show any ACTH variations connected with age. In conclusion, ACTH levels in basal conditions are not correlated to those of βLPH or βEP, either in the plasma or in CSF, while the two opioids show parallel changes. Moreover, the differences in the age-related changes of βLPH and βEP in plasma and CSF markedly sustain the existence of two different compartments in which proopiocortin-related peptides are subject to different forms of control. © 1983.