Sažeci 2. Hrvatskog kongresa medicinske biokemije - Klinički zavod ...

Sažeci 2. Hrvatskog kongresa medicinske biokemije
POSTERSKI RADOVI
na dan početka estrusa (dan 0), ali ta promjena nije bila značajna. U
isto vrijeme, izmjerena je najniža koncentracija P (0,42 ± 0,02 ng/ml)
i značajno (p < 0,001) niža koncentracija 17(3-E (28,0 ±1,1 pg/ml) u
odnosu na koncentraciju tog hormona 24 sata prije početka estrusa
(112,0 ± 15,6 pg/ml), što ukazuje na početak estrusa ispitivanih
životinja.
03/P5
BRAIN LIPIDS AND PROTEIN KINASES A AND C IN
THE HUMAN BRAIN DURING AGING
D. Mikačić, I. Kračun, S. Šale, T. Ariga, R.K. Yu
Croatian Institute for Brain Research, Zagreb University School of Medicine;
University of Virginia, Richmond, USA
According to our knowledge there is no study on the distribution
of different species of gangliosides and protein kinases A (PKA) and
C (PKC) in different brain regions in the adult human brain and
aging. Since the gangliosides or ceramide/sphingosine serve as pool
generating modulators of PKC and PKA in neuronal membranes, we
analvsed "a" and "b" series of gangliosides and protein kinases system
in distinct brain regions of the adult human brain and during
aging. We determined the distribution of gangliosides and activities
of PKA and PKC in 10 different regions of adult human brain (50
years of age, n = 3) and during age range 20 - 80 years (n = 20). Our
results demonstrated that PKC activity is differentially distributed
in the adult human brain showing the highest values in frontal cortex
(300 cpm/mg protein/h) and the lowest in mesencephalon, thalamus
and stratium (50 cpm/mg protein/h), similar to gangliosides concentration.
However, PKA activities were the highest in mesencephalon,
stratium and hippocampus but lowest in frontal cortex. During
human aging, gangliosides concentration and PKA activity in cortical
regions (frontal, visual and cerebellar cortex) increased until 40 years
and decreased until 80 years of age. We suppose that decreased concentration
of total gangliosides during aging might decrease PKC activity
in senescent cortical regions. Moreover, it seems that switch
from "a" series of gangliosides which are decreasing after 40 years of
age to "b" series of gangliosides which are increasing, might be a trigger
for decreased PKC activity in senescent human cerebral cortex in
Alzheimer's disease.
106 BIOCHEMIA MEDICA god. 6, br. 1, 1996