Thyroid and pituitary hormone responses to TRH in advanced nonalcoholic liver disease

Pituitary hormone circadian rhythm alterations in cirrhosis patients with subclinical hepatic encephalopathy

AIM: To analyze pituitary hormone and melatonin circadian rhythms, and to correlate hormonal alterations with clinical performance, hepatic disease severity and diagnostic tests used for the detection of hepatic encephalopathy in cirrhosis.

METHODS: Twenty-six patients with cirrhosis were enrolled in the study. Thirteen patients hospitalized for systemic diseases not affecting the liver were included as controls. Liver disease severity was assessed by the Child-Pugh score. All patients underwent detailed neurological assessment, electroencephalogram (EEG), brain magnetic resonance imaging (MRI), assays of pituitary hormone, cortisol and melatonin, and complete blood chemistry evaluation.

RESULTS: Pituitary hormone and melatonin circadian patterns were altered in cirrhosis patients without clinical encephalopathy. Circadian hormone alterations were different in cirrhosis patients compared with controls. Although cortisol secretion was not altered in any patient with cirrhosis, the basal cortisol levels were low and correlated with EEG and brain MRI abnormalities. Melatonin was the only hormone associated with the severity of liver insufficiency.

CONCLUSION: Abnormal pituitary hormone and melatonin circadian patterns are present in cirrhosis before the development of hepatic encephalopathy. These abnormalities may be early indicators of impending hepatic encephalopathy. Factors affecting the human biologic clock at the early stages of liver insufficiency require further study.

Hypothalamic-pituitary-thyroid (HPT) axis in chronic alcoholism. I. HPT axis in chronic alcoholics during withdrawal and after 3 weeks of abstinence

Thyroxine (T4), free T4 (fT4), triiodothyronine (T3), free T3 (fT3), reverse T3 (rT3), thyrotropin (TSH), thyroxine binding globulin (TBG), and T3 uptake were measured in 14 chronic alcoholics during withdrawal and after 21 days of abstinence. Results were compared with those of 16 healthy volunteers. During withdrawal, the fT4 and fT3 concentrations were subnormal, whereas the respective protein-bound fractions were normal. T4, T3, and TBG increased during the abstinence period, T3 and TBG being significantly higher than in normals at the second measuring time. T3 uptake values fell, but remained well within the normal range at both measuring times. During abstinence, the fT3 levels remained significantly lower than in healthy subjects. rT3 concentrations decreased, but not significantly. The TSH values were normal throughout. These results showed numerous abnormalities in the hypothalamic-pituitary-thyroid axis in alcoholics, the reasons for which are as yet unclear. The following possible interpretations are suggested: 1. The abnormally low serum fT3 and fT4 levels during withdrawal might reflect an increase in tissue uptake. 2. The increases in T4--and partly those in T3--during abstinence seem to reflect increased binding by TBG, the level of which rose markedly for reasons as yet unknown. 3. If increases in TBG during abstinence are taken into account, the decreases in rT3 concentrations may reach the level of statistical significance. These falls in rT3 concentrations may reflect an increase in rT3 metabolization (deiodination) in various tissues, including the CNS, leading to a reduction in serum rT3 bioavailability. 4. Factors such as liver disease, protein caloric malnutrition, and "psychological stress" do not fully explain all these abnormalities. A direct effect of ethanol on intracellular thyroid hormone metabolism and/or function seems conceivable.

Urinary growth hormone (U-GH) excretion and serum insulin-like growth factor 1 (IGF-1) in patients with alcoholic cirrhosis

Basal serum growth hormone (GH) levels are elevated and insulin-like growth factor 1 (IGF-1) concentrations in serum are suppressed in patients with chronic liver disease. The aim of this study was to measure the urinary GH (U-GH) excretion and IGF-1 concentrations in patients with cirrhosis and to correlate these both to clinical and biochemical characteristics and survival rate. Urinary GH excretion, IGF-1, and other biochemical parameters were measured in 36 patients with alcoholic cirrhosis, while in the control group of 34 healthy individuals only U-GH excretion was measured. U-GH excretion was significantly higher in patients than in the healthy controls (p < 0.00001), and increased with deteriorating liver function assessed by modified Child-Turcotte score (p < 0.01). The highest U-GH excretions were found in patients with hepatic encephalopathy (p < 0.003). IGF-1 levels were reduced in cirrhosis and correlated with liver function (p < 0.001). Serum IGF-1 concentrations below 3.1 nmol/l were associated with a poor prognosis (p < 0.004). The elevated U-GH in patients with alcoholic cirrhosis may reflect high serum levels of GH due to increased pituitary secretion or decreased hepatic degradation of GH. In addition, the IGF-1 levels reflect the degree of hepatic insufficiency and, thus, seem to provide new prognostic information.