Prolactin responses to thyrotrophin releasing hormone do not distinguish patients with isolated gonadotrophin deficiency from normals.

Prolactin secretion in response to TRH has been assessed in six patients with isolated gonadotrophin deficiency (IGD) and in eight normal controls. In all six subjects with IGD, serum oestradiol was below the detection limit of the method. There was no statistical difference between either the basal or maximum increment of serum prolactin between the two groups. Recent claims that prolactin responses to TRH distinguish constitutional delay of puberty from IGD have therefore not been supported.