Polypeptide & AA derived hormones
- Prominent RER and Golgi
- Secretory granules
- bind surface receptors
- Stain w/:
- -Synaptophysin
- -Chromogranin
- -PGP 9.5
Steroid hormones
- Cytoplasmic lipid bodies
- SER
- mitochondria
- Continuous Sythesis
- Bind nuclear receptors
- Stain w/ Melan A
Corticotroph adenoma (Hormone / Lesion / Clinical sign)
- ACTH –> cortisol secretion
- anterior pituitary neoplasia & Diffuse Bilateral Hyperplasia of adrenal cortex
-
Somatotroph adenoma (Hormone / Lesion / Clinical sign)
- GH and Insulin-like hormone
- anterior pituitary neoplasia, acromegaly
- PU/PD (insulin resistant)
Adrenocortical adenoma
–
Thyroid follicular cell adenoma
–
Thyroid C-cell adenoma
–
Parathryroid adenoma
–
Pancreatic islet cell adenoma
–
What cells are in the pars distalis
- mixed cell type
1. Acidophils
- GH, PRL
2. Chromophobes- ACTH
- Basophils
- ACTH, TSH, FSH, LH
- ACTH
- little stroma
- highly vascular
Pituitary disorders
- non-functional pituitary –> mass effect on hypothalamus
- Suprasellar neoplasms
- Pituitary adenomas (intermedia/distalis)
- Diabetes insipidus (neurohypophysis)
Dz’s of Pituitary gland
- Developmental disorders
- Postnatal disturbances of growth most common
- Degeneration /necrosis
- Inflammation
Developmental disorders
- Aplasia
- Failure of adenohypophyseal development (Cystic Rathke’s pouch)
- Cyst
Cystic Rathke’s Pouch
Oropharyngeal ECTOderm fails to differentiate to adenohypophysis
- -> fail to produce any trophic hormones
- -> Panhypopituitarism
-German shepherd dogs
Postnatal disturbances of pituitary
- Physiologic atrophy
- Proliferation
- hyperplasia
- neoplasia
- Microadenoma /Macroadenoma
Adenomas associated with Pars distalis
- Corticotroph adenoma –> ACTH
2. Somatotroph adenoma –> GH and Insulin-like hormone
Adenomas associated with Pars intermedia
- Corticotroph adenoma -DOGS
2. Melanotroph adeoma -HORSE
Pituitary Pars intermedia dysfunction(PPID) in horse (Hormone / Lesion / Clinical sign)
- CLIP, MSH, Endorphines
- Enlarged pituitary gland (intermedia)-can cause damage to dopaminergic neurons of Pars nervosa
Clinical signs (due to mass effect)
- long, matted hair coat
- lack of temp regulation
- adipose deposits
- NORMAL adrenal gland
Why is PPID, not a true cushing’s?
ACTH measures high in horses with PPID
- CLIP is structurally similar to ACTH, so it is detected by laboratory as ACTH
- However, adrenal glands are normal. Suggesting CLIP does not act like ACTH to secrete excess cortisol. –THEREFORE, it cannot be considered Cushings
Define hirsutism –whats its significance
Excessive hairy-ness
-horses with PPID will present with this.
2 suprasellar tumors
- Craniopharyngioma
2. Germ cell tumor
Main cause of Degeneration/ necrosis of pituitary
Compression via pituitary mass
-infarcts are rare
Inflammation in pituitary
- Immune mediated hypophysitis
- Systemic infection–hematogenous
- Adjacent inflammation
What hormones are produced in the Pars Intermedia? and whats special about the dog?
MSH and CLIP
-Dogs: ACTH
