Effect of prolactin and growth hormone on prolactin and LH receptors in the dwarf mouse

Summary. Dwarf mice (DW/J; dw/dw) which exhibit a deficiency of prolactin and GH secretion were treated for 8 days with ovine prolactin and/or human GH (10 or 20 \g=m\g/day)and the effect on hepatic and testicular prolactin receptors was investigated. In both sexes there was a significant increase in body weight after all hormone treat-ments, but an increment in testicular weight was observed only after prolactin adminis-tration. Prolactin treatment increased the specific binding % of prolactin in liver membranes in females but not males, and in testicular homogenates (together with an increase in LH receptors). The results suggest that lack of prolactin but not of GH retards sexual development in these mice. Treatment with prolactin partly coun-teracts this deficiency, and the effect may be mediated by the induction of hepatic and testicular prolactin and LH receptors