AGE-DEPENDENT DIFFERENCES IN THE BINDING OF [131] LH BY RAT TESTIS HOMOGENATES

Abstract

The specific binding of radioiodinated HCG and LH by homogenates of adult rat testes in vitro has been demonstrated by Catt, Dufau & Tsuruhara (1972). The binding sites were of high affinity and the uptake of HCG was greatest at 24° C, maximum uptake occurring by 24 hr of incubation under these conditions (Catt, Tsuruhara & Dufau, 1972). There have been no reports of comparable work on the binding of LH by the testes of immature rats, but Means & Vaitukaitis (1972) have demonstrated a greater uptake of [3H]FSH in vitro by immature than by mature rat testes. Changes in the characteristics of the gonadal receptors for LH could be a factor in the control of sexual maturation. The binding of 131I-labelled human LH ([131I]hLH) by testicular homogenates from immature and mature Porton rats was therefore compared using the methods of Catt, Dufau & Tsuruhara (1972) and