GABAergic alterations in hypothalamus during compensatory hyperplasia after
partial hepatectomy (PH), lead nitrate (LN) induced direct hyperplasia and
N-nitrosodiethylamine (NDEA) induced neoplasia in liver were investigated.
Serum GABA levels were increased in all 3 experimental groups compared wit
h the control. GABA content decreased in hypothalamus of PH and NDEA treate
d rats, while it increased in LN treated rats. GABA(A) receptor number and
affinity in hypothalamic membrane preparations of rats showed a significant
decrease in PH and NDEA treated rats, while in LN treated rats the affinit
y increased without any change in the receptor number. The GABA(B) receptor
number increased in PH and NDEA treated rats, while it decreased in LN tre
ated rats. The affinity of the receptor also increased in NDEA treated rats
. Plasma NE levels showed significant increase in PH and NDEA rats compared
with the control while it decreased in LN treated rats. The results of the
present study suggests that liver cell proliferation is influencing the hy
pothalamic GABAergic neurotransmission and these changes regulate the hepat
ic proliferation through the sympathetic stimulation.