Radioimmunoassay for Follicle-Stimulating Hormone in the Rhesus Monkey using an Anti-Human FSH Serum and Rat FSH131I1

Abstract

A sensitive double antibody radioimmunoassay for rhesus monkey follicle-stimulating hormone (FSH) has been developed utilizing an antiserum to human FSH in combination with radioiodinated rat FSH. Correlations between FSH content, as estimated by bioassay and by radioimmunoassay, approached unity for preparations with low LH to FSH ratios. The estimate of FSH content by radioimmunoassay was considerably higher than bioassay estimates for preparations with high LH and/or TSH content. However, when these preparations were subjected to polyacrylamide gel electrophoresis, in all cases the LH, TSH and FSH activities were clearly separated from each other as indicated by radioimmunoassay. This finding strongly suggested that LH or TSH did not influence the quantitation of FSH in this radioimmunoassay system. Serum per se did not influence the radioimmunoassay since 1) inhibition curves with serum were parallel to those obtained with pituitary extract used as standard, 2) no activity was detected in serum from hypophysectomized rhesus monkeys, and 3) varying amounts of exogenous FSH in the form of a partially purified pituitary preparation could be accurately measured in the presence of serum from normal female monkeys. The sensitivity of the assay system is sufficient to allow the measurement of FSH in 200 M-l of serum throughout the menstrual cycle. (Endocrinology92: 618, 1973)