Table. Overview of some commonly performed tests of pituitary function and remarks on practical aspects, the hormones to be measured, and the timing of blood drawing.

Test	Method of performance	Remarks	Hormones to be measured	Blood drawing
TRH test	1 amp (200 µg) TRH Duration of injection: >60 sec	Note: apoplexy occurs very rarely with large macroadenomas	TSH	0 min before
				injection
				then 30 min
GnRH test	1 amp (100 µg) LHRH Duration of injection: <30 sec	Note: apoplexy occurs very rarely with large macroadenomas	LH, FSH	0 min before
				injection,
				then 30 min
IHT	0.15 IU/kg BW regular insulin IV (in renal failure 0.1 IU/kg BW, for patients with abnormal glucose tolerance or acromegaly 0.2 IU/kg BW)	Patient fasting CI: epilepsy, CHD Secure venous access with an indwelling catheter A predrawn syringe with 20% glucose should be readily accessible in case of need Trained personnel should be near the patient at all times	GH, cortisol (- ACTH)	0 min before
				injection, then
				15 min, 30 min,
				45 min, 60 min,
				90 min, 120 min
CRH test	CRH 1 µg/kg BW IV, to be given immediately after dissolution. Duration of injection: <30 sec		Cortisol (- ACTH)	0 min before
				injection, then
				15 min, 30 min,
				45 min, 60 min
ACTH test	1 amp (250 µg) ACTH 1–24 solution for injection IV (must be shielded from light in refrigerator and in package). Shake before injection. Duration of injection: <30 sec		Cortisol	0 min before
				injection,
				then 30 min,
				60 min
GHRH/arginine test	GHRH 1µg/kg BW IV (can be stored at room temperature), use immediately after dissolution Duration of injection: <30 sec. then, infusion of 30 g arginine in 21.07% solution (7 amp = 30 g) over 30 min, diluted in normal saline. note: lower the arginine dose if bw <60 kg: give half the bw in grams, e.g., 50 kg → 25 g	Patient fasting	GH	0 min before
				injection,
				then 30 min,
				45 min, 60 min,
				90 min

There are many variations of the techniques above, particularly relating to the timing of blood draws. TRH, thyrotropin-releasing hormone; GnRH, gonadotropin-releasing hormone; IHT, insulin-hypoglycemia test; CRH, corticotropin-releasing hormone; ACTH, adrenocorticotropic hormone; GHRH, growth-hormone-releasing hormone; GH, growth hormone; CI, contraindications, CHD, coronary heart disease