Pituitary Tumors

Prolactinoma (Prolactin)

  • Bromocriptine (pergolide), and cabergoline (an ergot-derivative, is a potent dopamine receptor agonist on D2-Receptors ) are drugs acts on dopamine-receptors in lactophilic hypothalamus cells and causes thereby a suppression of the prolactin-production in pituitary gland.

Acromegaly (GH)

  • Somatostatin opposes the effects of Growth Hormone-Releasing Hormone (GHRH)
  • Octreotide and lanreotide are analogs of somatostatin (growth hormone-inhibitory hormone) that inhibit GH secretion more effectively than native somatostatin because of their greater potency and longer plasma half-life.

Cushing’s Disease (ACTH)

  • Mitotane suppresses cortisol production and lowers plasma and urine hormone levels. Treatment with mitotane alone can be successful in 30 to 40 percent of patients. Other drugs used alone or in combination to control the production of excess cortisol are aminoglutethimide, metyrapone, trilostane and ketoconazole.

Radiation Complications

  • Optic chiasm can tolerate 54 Gy in 1.8 Gy fractions (General Consensus)
  • No injuries were observed in 106 optic nerves that received a total dose of < 59 Gy in retrospective study. The 15-year actuarial risk of optic neuropathy after doses of > or = 60 Gy was 11% when treatment was administered in fraction sizes of < 1.9 Gy, compared with 47% when given in fraction sizes of > or = 1.9 Gy. (Parsons, Bova IJROBP: 1994 Nov 15;30(4):755-63. )
  • For single fraction tolerance is 8-10 Gy per institutional studies.

Functional Tolerance

Hormon Tolerance Dose Results
GH 18 Gy isolated GH deficiency
Prolatin 30-50 Gy 5-20% hyperprolactin
LH/FSH 50-70 Gy 20-50% deficiency
ACTH 50-70 Gy
TSH 50-70 Gy
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