A56 year old male came to the clinic one day because he said that his "hat doesn't fit anymore". i asked what he meant and he told me that the hats felt like they were getting smaller. he was curious if wearing them in the rain would make them shrink, but for the most part, that should not happen. he was then concerned that perhaps he was gaining weight, but his chart did not show any significant weight changes. he did note that his feet hurt at the end of the day than normal. i checked his feet and found no other abnormalities. his review of systems was within normal limits, though i did notice a slight change in his facial features. his nasolabial folds, the lines that go from his nose to the corners of his mouth, seem deeper and the characteristics of his face overall seemed coarser. i told him that i needed to draw some blood to check his hormone levels. what hormone would be implicated in the sudden increase in the circumference of this patient's head?