A 35 year old woman presents with heat intolerance and menstrual abnormalities. On examination, a diffusely enlarged thyroid gland is present. Which of the following features will not be present in her?
High-Yield Explanation
This woman has hypehyroidism. Thyroid hormone causes increased protein breakdown. Hence, she will not have decreased protein breakdown. Physiological effects of Thyroid hormone: Target Tissue Effect Mechanism Hea Chronotrophic and ionotrophic Increased number of b-adrenergic receptors Enhanced responses to circulating catecholamines Increased propoion of a-myosin heavy chain (with higher ATPase activity) Adipose Tissue Catabolic Stimulated lipolysis Muscle Catabolic Increased protein breakdown Bone Developmental Promote normal growth and skeletal development Nervous system Developmental Promote normal brain development Gut Metabolic Increased rate of carbohydrate absorption Lipoprotein Metabolic Formation of LDL receptors Other Calorigenic Stimulated oxygen comsumption by metabolically active tissues (exception: testes, uterus, lymph nodes, spleen, anterior pituitary) Increased metabolic rate Ref: Guyton and Hall 13th edition Pgno: 955, 957