Endo 1: Hyposecretion of Anterior Pituitary Hormones

Year 2 Endocrinology

Lecture 1: Hyposecretion of Anterior Pituitary Hormones

·         Primary endocrine gland disease – disorder of an endocrine gland (e.g. thyroid, gonads, adrenal cortex), resulting in deficiency/excess of the primary hormone.

·         Secondary endocrine gland disease – disorder of the anterior pituitary, so the stimulating anterior pituitary hormone is deficient/in excess.

·         Tertiary endocrine gland disease – disorder of the hypothalamus, so the releasing/inhibiting hormone is deficient/in excess.

Hypopituitarism – decreased production of all anterior pituitary hormones (pan-hypopituitarism) or of specific hormones.

Panhypopituitarism:

·         Congenital (developmental defects) and gene mutations (e.g. PROP1 Mutations) are both rare causes.

·         In adults, progressive loss of pituitary secretion often (but not invariably)  in the following order:

o   Gonadotrophins  (LH and FSH)

o   GH

o   Thyrotrophin

o   Corticotrophin

o   (Prolactin deficiency is uncommon, unrecognised?)

·         Includes Simmond’s disease, Sheehan’s syndrome and pituitary apoplexy.

Simmond’s disease:

·         Insidious in onset

·         Causes:

o   Various

o   Infiltrative processes (e.g. lymphocytic)

o   Pituitary adenomas

o   Craniopharyngiomas

o   Cranial injury

o   Following surgery

·         Symptoms, due to decreased thyroidal, adrenal and gonadal function:

o   Secondary amenorrhoea or oligomenorrhoea (in women)

o   Impotence (in men)

o   Loss of libido

o   Tiredness

o   Waxy skin

o   Loss of body hair

o   Hypotension, etc.

·         Diagnosis:

o   basal plasma values of pituitary or target endocrine gland hormones.

o   Particularly useful of measured after a ‘stimulation’ (or ‘provocation’) test. E.g. combined function tests, involving rapid sequential IV administration of GHRH, CRH, GnRH, and TRH.

o   Specific tests can…