This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology metabolism, Subject name: Physiology
Hyperthyroid state is characterized by - 
Select and explain. 
A. Increased protein synthesis, B. Decreased glycolysis, C. Lipolvsis, D. Increased cholesterol
C: Lipolvsis
Answer: C: Lipolvsis 
Explanation: Ans. is 'c' i.e., Lipolysiso In hyperthyroidism all effects of thyroid hormone are aggravatedCalorigenie effect Thyroid hormones enhance oxygen consumption, and hence the basal metabolic rate (BMR). This may be at least partly due to increase in the activity of membrane Na+/K+ ATPase. Thyroid hormones also increase the number and activity of mitochondria, which may be the cause or the effect of increase in oxygen consumption. By increasing the BMR, thyroid hormones raise body temperature, loss of body weight and increase urinary nitrogen loss.Growth and developmentThyroid hormones are essential for normal growth and development.iii) Carbohydrate metabolism Thyroid hormones have both hypoglycemic and hyperglycemic effects. The hypoglycemic effect is the increased glycolysis. The hyperglycemic effects are stimulation of glycogen olysis and glucoconeogenesis. The net effect is hyperglycemia and depletion of glycogen.Fat metabolism Thyroid hormone stimulates both lipogenesis and lipolysis. The lipolysis exceeds lipogenesis. Thus thyroid hormones moblize fat from adipose tissue, leading to an increase in plasma concentration of FFAs.Protein metabolism : - Thyroid hormone has a protein anabolic effect but in large doses, it has a protein catabolic effect. Thus thyroid hormone increases both protein synthesis and protein degradation.Cardiovascular effects The thyroid hormones increase the heart rate, cardiac contractility, stroke volume and cardiac output, and consequently also the systolic BP. But the diastolic BP may fall due to vasodilatation in several vascular beds with decrease in peripheral vascular resistance. The cardiovascular effects of thyroid hormones are partly mediated by potentiation of effects of catecholamines.GIT Thyroid hormones increase GI secretion, absorption and motility.Nervous system Thyroid hormones are essential for normal formation of synapses and mvelination in the developing brain.Respiratory system Thyroid hormones increase the rate and depth of respiration.About option a & do In low concentration thyroid hormone increases protein synthesis, but in high concentration (as in hyperthyroidism) it is catabolic.o Hyperthyroidism causes decrease in cholesterol due thyroxine induced increased LDL receptor synthesis in liver, and consequent increase in the removal of LDL from circulation.