Relationships among hypothalamic releasing and inhibiting hormones, the anterior pituitary hormones controlled by hypothalamic hormones, and their respective target organs or tissues.

Its 198 amino acid, single chain peptideMW-23000Secreted by lactotroph(mammotroph) cells

Hyperprolactinaemia

Galactorrhoea-Amenorrhoea-infertility syndrome

Causes of hyperprolactinaemia

-disorders of hypothalamus removing inhibitory control over pituitary

-Antidopamenergic and DA depleting drugs

-Prl secreting tumours

-Hypothyroidism with high TRH levels- inc. Prl secretion.

Bromocriptine

-Ergot derivative, 2-bromo-α-ergocryptine-potent dopamine agonist

Action

↓ Prl release from Pituitary

↓ GI motility

↑ GH release

HypotentionStimulate D2 receptor in

CTZ

Levodopa like action in CNS

Start at low dose 1.25 mg BD

1.Hyperprolactinemia

2.Acromegaly

3.Parkinsonism

Side effectsEarly- Nausea, vomiting, constipation etcLate- behavioral alterations, mental confusion.

Anterior pituitary secrets two Gns

FSH & LH

Function- promote gametogenesis and secretion of gonadal hormones.

FSH- in female

in male

Induces follicular growthDevelopment of ovamSecretion of estrogens

Supports spermatogenesis

Ovarian and testicular atrophy

LH

In Females-

In male-

Progesteron secretion occurs only under the influence of LH.

Induces preovulatory swelling of the ripe graafian follicle and triggers ovulation

Stimulates testosterone secretion

Disturbances of Gn secretion- Delayed puberty in girls and boys

Inadequate Gn secretion – amenorrhoea & sterility in women impotence and infertility in men

Uses1.Amenorrhoea and infertility

2.Hypogonadotrophic hypogonadism in males

3.Cryptorchism

4. To aid in vitro fertilization

Adverse effects

ovarian hyperstimulation- polycystic ovary, pain in lower abdomen

It is 210 amino acid, two chain glycoproteinMW 30000

FUNCTIONS

Stimulates thyroid to synthesize and secrete thyroxin (T4) & Triiodothyronin (T3)

-Induces hyperplasia & hypertrophy of thyroid follicles

-Promotes trapping of iodide by thyroid

-Promotes organification of trapped iodine & its incorporation into T3 & T4 By increasing Peroxidase activity

-Enhances endocytotic uptake of thyroid colloid by the follicular cells

-Proteolysis of thyroglobulin to release more T3 & T4.

39 amino acid single chain peptide

MW- 4500

Derived from larger peptide pro-opio melanocortin (MW 30,000)

Function- - promotes steriodogenesis in adrenal cortex by stimulating formation in cortical cells- Increase the availability of cholesterol for conversion to pregnenolone

Excess production- Cushing’s syndrome

USES

Diagnosis of disorders of pituitary adrenal axis

Injected 25 IU i.v. causes increase in plasma cortisol if adrenals are functional.