CRH (CORTICOTROPIN RELEASING HORMONE) TEST

Purpose

To investigate corticotropic function using CRH or CRF (Corticotropin Releasing Factor) or corticoliberin.

Subject preparation

Subject fasting for 12 hours and lying down for 30 minutes.

Product

CRH

Dose

1 µg/kg body weight (do not exceed 75 µg).

Protocol

• The challenge must be administered at 8 a.m.
• Commence the perfusion of normal saline 30 minutes before the challenge.
• Samples (dry tubes for the cortisol and EDTA + aprotinin tubes for the ACTH) at time intervals: - 15 min (T-15) and 0 (T0).
• IV injection of the correct dose of CRH over one minute.
• Samples at time intervals T+15, T+30, T+60 and T+120 min.

Samples

After centrifugation, draw off serum and plasma. Freeze plasma (to be used to assay ACTH) immediately and store serum (to be used to assay cortisol) at +4°C.

Assays

ACTH and cortisol.