Glycerol prevents loss of immunoreactive follicle-stimulating hormone and luteinizing hormone from frozen urine

Abstract

First morning urine samples were collected from both menstruant and post-menopausal women and stored at −25 °C. Immunoreactive FSH disappeared from these samples (t½ = 30 days), ultimately stabilizing at about 20% of the initial value. The loss was more rapid at −20 °C and less rapid at −55 °C and +4°C. Immunoreactive LH was also lost from frozen urine, but more slowly than FSH. The addition of glycerol to urine (0·52 mol/l) stored at −25 °C prevented loss of immunoreactive FSH and LH for at least 105 days.