Normal Prenatal but Arrested Postnatal Sexual Development of Luteinizing Hormone Receptor Knockout (LuRKO) Mice

To study further the role of gonadotropins in reproductive functions, we generated mice with LH receptor (LHR) knockout (LuRKO) by inactivating, through homologous recombination, exon 11 on the LHR gene. LuRKO males and females were born phenotypically normal, with testes, ovaries, and genital structures indistinguishable from their wild-type (WT) littermates. Postnatally, testicular growth and descent, and external genital and accessory sex organ maturation, were blocked in LuRKO males, and their spermatogenesis was arrested at the round spermatid stage. The number and size of Leydig cells were dramatically reduced. LuRKO females also displayed underdeveloped external genitalia and uteri postnatally, and their age of vaginal opening was delayed by 5–7 days. The (−/−) ovaries were smaller, and histological analysis revealed follicles up to the early antral stage, but no preovulatory follicles or corpora lutea. Reduced gonadal sex hormone production was found in each sex, as was also reflected by the suppr...