[The effect of streptozotocin-induced diabetes in the neonatal period on hepatic mitochondrial bioenergetics in adult rats].
BACKGROUND
Previous experimental studies focused on the liver mitochondrial bioenergetic changes in diabetes mellitus type I induced in adult animals. Information about the effects of persisting neonataly induced diabetes mellitus type I on the mitochondrial bioenergetics are missing.


OBJECTIVE
The aim of the study was to assess the degree of diabetes mellitus compensation and parameters of oxidative phosphorylation in rats aged 3 months with DM persisting from neonatal period.


METHODS
DM was induced in male Wistar rats by repeated intraperitoneal administration of streptozotocine 45 mg/kg on 2nd and 9th day after birth. The concentrations of glucose, glycosylated haemoglobin, fructosamine were detected in the blood and the concentration of cholesterol and triacylglycerols in the blood and liver tissue, respectively. After mitochondria isolation from the liver we measured parameters of oxidative phosphorylation by polarography using Clark oxygen electrode.


RESULTS
In the group of neonataly induced DM the concentration of glucose (23.10 +/- 1.55 vs 8.3 +/- 0.56 mmol/l), glycosylated haemoglobin (6.04 +/- 1.17 vs 3.99 +/- 0.44%) and blood cholesterol concentration (2.15 +/- 0.11 vs 1.83 +/- 0.09 mmol/l) increased significantly (p < 0.001 and p < 0.005 for cholesterol) comparing to a group of healthy rats. No statistically significant differences were found in the remaining parameters when comparing these two groups. The parameters of oxidative phosphorylation were significantly (p < 0.001) decreased in the group with DM comparing to control group of healthy animals--the index of respiratory control (4.87 +/- 0.25 vs 9.57 +/- 0.34), the rate of oxygen consumption in the stage 3 in ADP presence (88.61 +/- 4.62 vs 165.08 +/- 4.5 natO.mg/protein/min) and phosphorylation rate (203.54 +/- 7.26 vs 332.87 +/- 7.39 nmolATP.mg/protein/min) with NAD substrate glutamate. Similar trend was also seen with FAD substrate succinate. The index of oxidative phosphorylation ADP:0 was not changed in both groups.


CONCLUSIONS
In 3 months old rats with neonataly induced DM the development of steatosis was not observed and uncoupling of oxidative processes from phosphorylation did not appear. Energy production was sufficient enough for normal functions of the liver and to ensure all needs of the organism. (Tab. 4, Ref. 51.)
Ulicná
O
O
Farmakobiochemické laboratórium III, Lekárskej fakulty Univerzity Komenského v Bratislave.
Zlatos
L
L
Holzerová
J
J
Kvaszová
E
E
Cársky
J
J
Gvozdjáková
A
A
Kucharská
J
J
Bada
V
V
D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D008297:Male; D008930:Mitochondria, Liver / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin
D013311:Streptozocin