SUBSTANCE-P MODULATING EFFECT ON THE BINDING-CAPACITY OF HAMSTER LEYDIG-CELL LH RECEPTORS

The influence of Substance P was studied on the binding characteristic s of LH receptors in purified Leydig cells collected from golden hamst ers kept under natural long or short days. Substance P exerted a diffe rential effect on the binding capacity of LH receptors. A significant increase in Bmax was estimated in Leydig cells obtained from young ham sters living under long days. Tn contrast, Substance P reduced the num ber of the LH binding sites in Leydig cell cultures prepared from adul t hamsters housed under short-day conditions.