Abstracts
2000 Digestive Disease Week

# 2225 Hepatic Clearance Is Reduced in Patients with Clinical Hypothyroidism.
Johanna M. Inkinen, Juhani A. Sand, Jorma Salmi, Vaino Turjanmaa, Pentti Vehkalahti, Isto H. Nordback, Tampere, Finland

Background: Previously we have shown that there is an increased prevalence of diagnosed hypothyroidism in common bile duct stone (CBD) patients, compared to gall bladder (GB) stone patients or age, sex and hospital admission adjusted controls. We have also shown that thyroxine (T4) has a strong inhibitory effect on sphincter of Oddi (SO) contractility in an ex vivo preparation. This inhibitory effect is similar between T4 and triiodothyronine, but is weak or lacks in the steroid hormones, and is mediated via K+- channels (Gastroenterology 1998; vol 114, G2135). In hypothyroidism SO may not relax properly, which can cause biliary stasis and thus favour the forming of CBD stones. The present study was done to test whether changes in the thyroid function affect biliary function. Material and methods: Six female patients, age mean 48 (range 35-62) years, with diagnosed untreated hypothyroidism (one patient) or total thyreoidectomy performed due to thyroid cancer (five patients) were taken into the study. They all had GB in situ. Quantitative 99mTc HIDA dynamic isotope biligraphy, biliary ultrasonography, and serum laboratory analyses were performed in two stages in each patient: 1) in hypothyroidism before the beginning of thyroxine therapy and 2) in euthyroidism. Results: In euthyroidism (serum unbound T4 17.3±1,3 pmol/l, S-TSH 1,7±0,4 mU/l and in hypothyroidism (serum unbound T4 4,6±0,4 pmol/l, S-TSH 84,4±12,7 mU/l) (mean±sem) no changes were seen in GB or bile ducts in ultrasonography. In 99mTc HIDA the hepatic maximal uptake (22±2 vs. 22±3 min) and appearance to the large bile ducts at the hilum (8±1 vs. 7±1 min) was similar in euthyroidism and hypothyroidism. Hepatic clearance at 60 min was decreased (67±2 vs. 54±7 %; p=0.05) and the hilum duodenum time increased from 13±2 min by 31 % in hypothyroidism. Conclusion: We conclude that hypothyroidism has an effect on the biliary dynamics. This might be explained by delayed biliary emptying. Such a finding is in accordance with our previous findings of inhibitory T4 effect on SO contractility.