Abstract
We examined the possibility that abnormalities of growth hormone (GH) release in cirrhotic patients were related to a reduction in the ratio of branched chain amino acids (BCAAs) to aromatic amino acids (AAAs) in plasma.
The intravenous infusion of 250 μg of thyrotropin-releasing hormone (TRH) caused a significant rise in plasma GH greater than 5 ng/ml and more than twice as much as the basal levels in 7 out of 15 patients (responders) but an insignificant rise in the remaining patients (non-responders). The difference in the basal GH level was not significant. The oral glucose load suppressed plasma GH in all of the normal subjects and 6 of 7 non-responders, while it was elevated in 6 of 7 responders and one of the non-responders. The ratio of BCAAs to AAAs in the plasma of cirrhotic patients was 1.21±0.38, which was significantly lower than that of normal sub jects (3.31±0.42, p<0.01). In addition, there was a significant difference between responders and non-responders in the ratios (0.96± 0.22 vs 1.42±0.36, p<0.05). An inversely significant correlation (p<0.05) between the ratios of BCAAs to AAAs in plasma and the peak levels of GH after TRH injection was observed when all subjects were combined, but no correlation was found between the ratios and the peak levels of GH after oral glucose loading. There were also significant correlations (p<0.01) between the ratios and various parameters including the serum albumin, cholinesterase and indocyanine green disappearance rate constant (KICG).
These data suggest that the derangement of the central monoaminergic mechanism related to the decreased ratio of BCAAs to AAAs might participate in the abnormal responses of GH to TRH and glucose load often observed in patients with liver cirrhosis.
