TROPIC HORMONE FEEDBACK

Paraventricular Nucleus (PVN) Produces

TRH, CRH, Somatostatin

Preoptic Area (POA) produces

GnRH

Arcuate Nucleus produces

GHRH, GnRH, Dopamine

Hypothalamus: TRH

Prolactin, TSH

Hypothalamus: CRH

ACTH

Hypothalamus: GnRH

LH, FSH

Adenohypophysis: TSH

Thyroid gland, T3, T4

Adenohypophysis: ACTH

Adrenal gland, glucocorticosteroids/cortisol

Adenohypophysis: LH, FSH

Gonads

Adenohypophysis: GH

Liver, IGF1

Adenohypophysis: Prolactin

Mammary, oxytocin

TSH regulation

T3 and T4 negatively inhibit hypothalamus/pituitary. Leptin in body fat also feeds back.

ACTH regulation

cortisol negatively feeds back hypothalamus/pituitary, but stress can override this

GnRH regulation in FEMALES

More LH/FSH causes follicle cells to grow. Follicle cells produce estradiol, which positively stimulates LH. Spike of LH causes follicle to rupture, ovulation occurs. Corpus luteum produces progesterone, to negatively inhibit LH.

GnRH regulation in MALES

more LH/FSH. Support cells produce ABP, and interstitial cells produce testosterone. More sperm is produced. testosterone negatively feeds back hypothalamus/pituitary

GH Regulation

Growth hormone stimulates the production of somatostatin, which inhibits GHRH. IGF1 also negatively inhibits Hypothalamus/pituitary

Prolactin Regulation

Prolactin is inversely regulated by dopamine. Mammary glands release oxytocin, positively stimulating prolactin.