Undetectable levels of serum FSH immunoactivity and bioactivity in girls with sexual precocity due to ovarian cysts.

Clinical presentation and endocrine investigations in five girls with precocious sexual development due to ovarian cysts are presented. These girls had pubertal oestradiol and suppressed gonadotrophin responsiveness to LHRH stimulation. FSH bioactivity as measured by the rat aromatase assay was undetectable in basal and LHRH-stimulated serum samples but our results cannot exclude the possibility of the presence of a species-specific follicle stimulating factor in these patients. IM injection of depot medroxyprogesterone acetate controlled pubertal development in two children.