The hypogonadal mouse pituitary contains bioactive LH

Saline extracts of pituitary glands from normal and hpg male mice were assayed for LH by the testosterone production assay. The extract of hpg pituitary tissue stimulated testosterone production by mouse Leydig cells in a dose-dependent manner which paralleled that of normal mouse pituitary. The normal mouse pituitary was about 20 times as potent as hpg pituitary which is similar to the relative potency obtained by radioimmunoassay. These results show that differentiation of the gonadotrophs and the synthesis of some biologically active LH can occur in the absence of LHRH.