Download - Prolactin hormone
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.