INTRODUCTION A disturbed regulation mechanism of arginine vasopressin secretion in response to plasma osmolality and volaemia changes occurs in hypothyroidism. The aim of this study was to determine plasma arginine vasopressin concentration in hypothyroid women under conditions of a low sodium diet and in an upright position. MATERIAL AND METHODS Twenty-six women with primary hypothyroidism a...

Lipoprotein lipase (LPL) is an important enzyme in lipid metabolism, and adipose LPL activity is increased in rats that are deficient in thyroid hormone. To examine the mechanism of thyroid hormone's effect on LPL, LPL gene expression was assessed in the epididymal fat pads of hypothyroid rats. When compared to control rats, LPL activity, mass, and synthetic rate in hypothyroid rats were increa...

BACKGROUND There is substantial evidence both in humans and in animals that a prolonged reduction in plasma thyroid hormone concentration leads to reproductive problems, including disturbed folliculogenesis, impaired ovulation and fertilization rates, miscarriage and pregnancy complications. The objective of the present study is to examine the consequences of chronic hypothyroidism, induced in ...

Lack of thyroid hormones may affect the composition and structure of the interstitium. Hypothyrosis was induced in rats by thyroidectomy 4-12 wk before the experiments. In hypothyroid rats (n = 16), interstitial fluid pressure measured with micropipettes in hindlimb skin and muscle averaged +0.1 +/- 0.2 and +0.5 +/- 0.2 mmHg, respectively, with corresponding pressures in control rats (n = 16) o...

Collagen biosynthesis is a multistep process that starts with the transcription and translation of the individual collagen gene. It is characterized by the presence of a large number of co- and posttranslational modifications. Hydroxylysine is found only in animal proteins and mostly in collagens. Procollagen lysyl hydroxylation is the first step in collagen biosynthetic pathway and lysyl hydro...

Changes in enzymatic and structural properties of ventricular myosin in thyrotoxic rabbit hearts have been investigated extensively. However, there is little information regarding the effect of thyroid hormone on the atrial myosin. In this study, we have compared enzymatic and structural changes of ventricular and atrial myosin from euthyroid, hypothyroid, and hyperthyroid rabbits. In euthyroid...

OBJECTIVE Prolonged cardiac contraction and relaxation in hypothyroidism are in part related to diminished expression of the gene coding for the calcium pump of the sarcoplasmic reticulum (SERCA2a). Therefore, we examined whether or not transgenic SERCA2a gene expression in mice may compensate for the cardiac effects of hypothyroidism. METHODS SERCA2a mRNA and protein were analyzed from heart...

Evidence is presented that modulation of the maximum velocity of a particulate low K,,, cyclic adenosine 3’:5’-monophosphate (cyclic AMP) phosphodiesterase by thyroid hormones is one mechanism for the regulation of the responsiveness of rat epididymal adipocytes to lipolytic agents such as epinephrine and glucagon. Fat cells of propylthiouracil-induced hypothyroid rats are unresponsive to lipol...