Thread by @BukuEndo

Hormones are tightly regulated🔄

For most we use a “neuroendocrine” system:

- a control centre in 🧠 (hypothalamus & pituitary) which integrate feedback & send signals (⬇️⬆️) to the

- primary endocrine glands (e.g. thyroid) re. how much “effector hormone” to make

"Tropic" hormones (e.g. corticotropin aka ACTH) signal to another endo gland.

"Effector" hormones have widespread targets throughout the body & usually affect processes e.g. growth, metabolism 👶👧👩‍🦰
They also ‘feed back’ on the control centre 🔄

Tropic hormones include ACTH, TSH, FSH, LH and GH (anterior pituitary) 🧠.

Their respective effector hormones are cortisol, thyroid hormones (T3/T4), oestradiol/testosterone & IGF-1.

The “primary” gland is the one which makes the effector hormone – problems in this gland cause PRIMARY hyper/hypo function (-ism).

The “secondary” gland is the control centre so problems with this gland cause SECONDARY hypo/hyper function (-ism).

Example:
1ry hypothyroidism: the thyroid gland doesn’t make enough T3/4 (effector) hormone.

2ry hypothyroidism: the pituitary doesn’t send enough TSH (tropic hormone) to the thyroid, so in turn it doesn’t make enough T3/4.

Outcome is the same; cause is v different! 💡