Pseudomalabsorption of levothyroxine: a case report.

A 51-year-old woman who had been treated with levothyroxine sodium because of hypothyroidism after total thyroidectomy for thyroidal cancer was admitted to our hospital for persistent hypothyroidism despite large dose administration of levothyroxine (600 microg/day). The patient complained of severe general fatigue and body weight gain. Free thyroxine, free triiodothyronine and thyrotropin levels were 0.97 ng/dl, 1.55 pg/ml and 24.51 microU/ml, respectively, under oral administration of levothyroxine. Levothyroxine loading test performed by liquid form, pulverized tablets via nasogastric tube and intravenous administration revealed no evidence of malabsorption or metabolic disorder of levothyroxine, although oral intake of tablets was ineffective due to her factitiousness. We report here a possible case of "pseudomalabsorption of levothyroxine" to emphasize the clinical recognition of this disorder in patients with resistant hypothyroidism.

Differential glomerular response to continuous infusion of vasopressin in spontaneously hypertensive rats and Wistar-Kyoto rats.

To determine the difference of glomerular response to exogenous vasopressin (VP) in vivo between normotensive and hypertensive rats, we examined the effects of 14-day continuous infusion of VP (1.0 ng/kg/min) on the physiological and histological aspects in 7-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. VP infusion did not result in significant changes in systolic blood pressure, heart rate, serum electrolytes, serum creatinine, urinary protein and N-acetyl-beta-glucosaminidase levels in both strains of rats. VP infusion significantly reduced daily urine volume associated with significant concentration of the urine in WKY rats but not SHR. Kidney and heart weights did not differ significantly after VP infusion between both strains. Glomerular mesangial expansion was significantly enhanced in VP infused SHR, but glomerular cellularity was not different between both strains following treatment. Competitive reverse transcription-polymerase chain reaction revealed that the level of glomerular transforming growth factor (TGF)-beta1 mRNA was significantly higher in SHR than WKY rats, and that this difference was significantly augmented after VP infusion in SHR. VP infusion, however, did not change the level of glomerular mRNAs of platelet-derived growth factor (PDGF) B-chain in both strains. Then, exogenous VP infusion contributes to the glomerular mesangial expansion in SHR, which involved overexpression of glomerular TGF-beta1 without any pressor effect. In contrast, the significant changes of glomerular expansion and TGF-beta1 level were not shown in WKY rats. These findings suggest that the glomerular response to the exogenous VP is preferentially enhanced in SHR.