Reconstituting & Diluting Gonadotropic Hormones

The following guidelines are recommended handling procedures, offered only to assist the user in maximizing product integrity. Scripps Laboratories makes no claims regarding product stability.

Use either borosilicate glass or polypropylene containers. Do NOT use polystyrene or polyethylene containers.

Hormones should be reconstituted in the presence of a protease-free carrier -- e.g., 0.1-1% ovalbumin, BSA, or gelatin -- and a suitable antimicrobial agent. Stock solutions should be prepared to ≥1 mg/ml or to an equivalent unit concentration, based on the unit activity and protein content of the vial. The following general guidelines may be useful:

Equilibrate the hormone to ambient room temperature before attempting to resuspend. After resuspending with buffer, allow to sit for at least 30 minutes at 2°C to 8°C to ensure complete solubilization.

  • Ovalbumin is generally used when assaying for gonadotropin.

  • If BSA is used, it must be free of gonadotropins and proteases (either crystalline or RIA grade is generally satisfactory).

  • Heat gelatin solutions to 60°C for maximum solubility (1% gelatin for ELISAs, 0.1% for solid phase assays).

  • Recommended dilution buffer for the pituitary hormones hFSH, hLH, hPRL, and hTSH: 
    10 mM Sodium Phosphate, 150 mM Sodium Chloride, 1 mg/ml BSA, 0.1% Sodium Azide, pH 7.4 is generally satisfactory for hFSH, hLH, hPRL, and hGH.

  • Recommended dilution buffer for hCG and hGH: 
    100 mM Tris, 1 mg/ml BSA, 0.05% Sodium Azide, pH 8.0 is generally satisfactory for hCG and hGH.

  • Avoid re-lyophilization, as this will cause the hormone to lose significant activity. If material is re-lyophilized, it should be assayed again prior to use.

      • Do NOT freeze-thaw reconstituted samples repeatedly. The reconstituted hormone should be subdivided into working aliquots and stored at -15°C or colder as soon as possible after resuspension.

      • Reconstituted samples are normally stable for at least 2-6 months when stored frozen; however, this depends on the hormone concentration, buffer/stock solution composition, and handling conditions.