Solid-Phase Assay for Luteinizing Hormone in Mouse Plasma

Abstract

A solid-phase tube assay for measuring LH levels in mouse plasma is described. The assay utilizes an antiserum to ovine LH and ovine LH standards and it measures LH levels in 20 III of plasma with a sensitivity of less than 0·6 ng/m!. Various parameters affecting the sensitivity and specificity of the assay were investigated. Serial dilutions of plasma from pregnant mice, a pituitary homogenate from mice and plasma from hypophysectomized mice, injected subcutaneously with ovine LB, ran parallel with ovine LH standards in plasma from hypophysectomized mice and plasma with low LH levels from intact mice. Ovine TSH showed about 12 % cross reaction in the assay system, whilst rat FSH and prolactin and also ovine FSH, prolactin and GH showed practically no cross reaction. Measurements of plasma LH levels have been made in hypophysectomized mice after injection with different vehicles containing 10 or 50llg LH or 50llg FSH per animal. Daily measurements of LH levels throughout pregnancy in the mouse show a rise in LH level prior to implantation and a further rise around mid-pregnancy which drops off sharply to levels which remain fairly constant until parturition when there is another rise.