Radioreceptor assay for cynomolgus monkey serum luteinizing hormone

Area of Science:

• Reproductive Endocrinology
• Primate Physiology
• Assay Development

Background:

• Accurate measurement of serum luteinizing hormone (LH) is crucial for understanding reproductive endocrinology in non-human primates.
• Existing methods may lack the sensitivity or specificity required for precise LH quantification in cynomolgus monkeys.

Purpose of the Study:

• To develop and validate a reliable radioreceptor assay (RRA) for quantifying serum LH in cynomolgus monkeys.
• To assess the utility of the developed RRA for monitoring hormonal changes during the menstrual cycle.

Main Methods:

• A radioreceptor assay (RRA) was established using rat testicular interstitial cells as the receptor preparation and 125I-LH (LER-960) as the radioligand.
• Assay validation included assessment of accuracy, precision, sensitivity, recovery, and intra-/inter-assay variability.
• Serum LH levels were measured in adult female cynomolgus monkeys throughout their menstrual cycle.

Main Results:

• The developed RRA demonstrated good accuracy, precision, and sensitivity (equivalent to 3.1 µg LER-907/ml serum).
• Recovery experiments showed a mean recovery of 86 ± 13% for added cynomolgus pituitary LH.
• Intra- and inter-assay coefficients of variation were 7% and 9%, respectively, indicating assay reliability.
• Cyclic changes in serum LH were successfully determined during the menstrual cycle in the studied monkeys.

Conclusions:

• The developed radioreceptor assay (RRA) provides a reliable and sensitive method for measuring serum LH in cynomolgus monkeys.
• This validated assay is suitable for investigating reproductive physiology and hormonal fluctuations in this primate model.