The subject who was diagnosed with secondary hypothyroidism was given levothyroxine (synthetic T 4 ). After 6 weeks of treatment, her TSH values did not change and her T 4 levels increased by 778.62...

The subject who was diagnosed with secondary hypothyroidism was given levothyroxine (synthetic T₄). After 6 weeks of treatment, her TSH values did not change and her T₄ levels increased by 778.62 %. Explain the why TSH did not change and why T₄ increased.