Pituitary

The pituitary is the master endocrine gland, under hypothalamic control. It releases TSH, ACTH, growth hormone, prolactin, FSH, and LH among others, each governing a downstream gland or tissue.

TSH is not just a thyroid signal

TSH itself has direct, inflammatory effects on tissue well beyond the thyroid gland, which is part of why "normal" lab TSH is insufficient evidence of adequate tissue thyroid function:

TSH has direct actions on many cell types other than the thyroid, and probably contributes directly to edema, fibrosis, and mastocytosis.

— Ray Peat

Since TSH produces reactions in cells as different as fibroblasts and fat cells, pigment cells in the skin, mast cells and bone marrow cells...

— Ray Peat

A direct laboratory demonstration of this: in cultured orbital fibroblasts, 100 ng/mL of TSH-receptor-stimulating antibody increased hyaluronic acid production 2.1-fold, and 10 U/liter of bovine TSH itself increased it 1.9-fold, a non-thyroid tissue effect distinct from the gland-level "thyroid signal" TSH is usually treated as.

He framed adequate T3/T4 as suppressing this pro-inflammatory TSH signal, on top of thyroid hormone's own separate anti-inflammatory actions:

In the 1950s, shortly after it was identified as a distinct substance, T3 was found to be anti-inflammatory, and both T4 and T3 have a variety of anti-inflammatory actions, besides the suppression of the pro-inflammatory TSH.

— Ray Peat

Reading the whole pattern

Because TSH rises under stress and low-energy conditions independent of the thyroid gland's own health, and because prolactin similarly tracks serotonin and estrogen pressure rather than a single clean signal, this site's framework reads temperature, pulse, and symptoms alongside pituitary labs rather than any single hormone number in isolation.

See also

• Thyroid
• TSH
• Prolactin
• Stress
• Hypothalamus