TABLE 31-1

Hypophysiotropic Hormones of the Human Hypothalmus

Hormone

No. AA2

(MW)

Gene

(human)

Origin1

(Prod. Site)

Functions

Mechanism of Action

Gonadotropin Releasing

Hormone GnRH (LHRH)

1 0

(U 82)

8

p

2 1

-q ll

. 2

PON, OVLT

Stimulates LHand FSH secretions

Gq a-PLCj3-Ca2+ -PKC

Corticotropin Releasing

Hormone (CRH)

41

(4,758)

8ql3

PVNparv

Stimulates POMC synthesis and

processing (ft ACTH secretion)

Gsa-AC activation

GH Releasing Hormone (GHRH)

44

(5,040)

2 0

TIDA

(Arcuate, VMN)

Stimulates GH secretion

Gsa-AC activation

Somatostatin SS (SRIH)

14

(1,638)

3q28

PeriVN,

PVN

parv,

PON

Inhibits GH secretion, also inhibits

TSH secretion

Gia-AC inhibition

Thyrotropin Releasing

Hormone (TRH)

3

(362)

PVNparv,

PeriVN

Stimulates TSH secretion, also

stimulates PRL release

GQa-PLQ3 -Ca2+-PKC

Prolactin Inhibiting Hormone

PIH (Dopamine)

na

(153)

na

TIDA

(Arcuate, VMN)

Inhibits PRL release, also indirectly

inhibits LH, FSH release

Gia-AC inhibition

(D2)

Prolactin Releasing Factor (PRF)

unknown

Stimulates PRL release

1

PeriVN = periventricular nucleus; PVN/rarv = parvicellular paraventricular nucleus; PON = preoptic nucleus; OVLT = organum vasculosum of the lamina terminalis; VMN = ventromedial nucleus;

TIDA = tuberoinfundibulardopaminergic system; 2AA = amino acid residue; MW = molecular weight; na = not applicable.