Pregnenolone levels have been shown to remain in the normal range in patients with Cushing syndrome and hyperaldosteronism. Levels can be suppressed with dexamethasone inhibition and increased with exogenous ACTH stimulation. Pregnenolone levels have been shown to be elevated in patients with idiopathic hirsutism. Since the various forms of congenital adrenal hyperplasia (CAH) result from enzymatic defects in the adrenal steroidogenic pathways, measurement of pregnenolone levels can be useful in diagnosis. Pregnenolone levels tend to be elevated in several forms of CAH, particularly in 17α-H deficiency and 3β-HSD deficiency since these enzymes catalyze steps immediately after pregnenolone in the steroidogenic pathways.

Gold serum separator (SST) tube

Immediately following collection, thoroughly mix sample by gently inverting 5 times

1. Allow sample to clot for a minimum of 30 minutes
2. Spin within one (1) hours of sample collection
3. Transfer serum to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as serum
4. Freeze

Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)

Red serum vial/tube - 5 mL

Lavender (EDTA), 4mL

Dk green heparin (Li or Na), no gel

Lavender/Dk green:

Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times to prevent clotting

Lavender/Dk green:

1. Spin within one (1) hour of specimen collection
2. Transfer plasma to a  Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as the appropriate plasma type
3. Freeze

Red:

1. Allow sample to clot
2. Spin within one (1) hour of specimen collection
3. Transfer serum to a  Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as serum
4. Freeze

Frozen (preferred) - 2 years

Freeze/thaw cycle: Stable x 3

Liquid chromatography/tandem mass spectrometry (LCMS-MS)

Adults: < 151

In humans, steroid hormones are produced by the adrenal glands and the gonads. The formation of pregnenolone from cholesterol is the first step in steroidogenesis and is mediated by the proteolytic enzyme, single cholesterol side-chain cleavage enzyme (P450 scc). Steroidogenesis continues along two paths from pregnenolone. 17-Hydroxypregnenolone is produced from pregnenolone through the enzymatic action of 17α-hydroxylase (17α-H).

Alternatively, pregnenolone is converted to progesterone through the enzymatic action of 3β-hydroxysteroid dehydrogenase (3β-HSD).  Pregnenolone levels have been shown to remain in the normal range in patients with Cushing syndrome and hyperaldosteronism. Levels can be suppressed with dexamethasone inhibition and increased with exogenous ACTH stimulation.

Pregnenolone levels have been shown to be elevated in patients with idiopathic hirsutism.  Since the various forms of congenital adrenal hyperplasia (CAH) result from enzymatic defects in the adrenal steroidogenic pathways, measurement of pregnenolone levels can be useful in diagnosis. Pregnenolone levels tend to be elevated in several forms of CAH, particularly in 17α-H deficiency and 3β-HSD deficiency since these enzymes catalyze steps immediately after pregnenolone in the steroidogenic pathways.