Might the cause of severe and chronic constipation be related to something within the htp axis even with normal tsh, t3, (liothyronine) and t4 levels?

Constipation: More than likely your constipation is diet related. Add more fiber to your diet in form of fruits and vegetables, nuts, figs prunes, dates, dried apricots and raisins. Add high fibered cereal to your diet and cut down on milk and milk products.

"Pop" diagnosis: You're already on prednisone. "hypothalamic-pituitary axis" disorders as a popular notion somewhere at the borderland between alternative-complimentary and mainstream. I trust you drink water ; have already looked at the habit, diet, fitness and medication angles. Porphyria, lead poisoning, iron / calcium supplements, and chagas's are only a few of the causes that may be overlooked in the workup.