Hormonal Pattern of Plasma LH, FSH and Prolactin in Girls with Premature Thelarche and Advanced Bone Age: A Synonym for Precocious Puberty

Summary

Three girls with premature thelarche and advanced bone age of at least 2 years are investigated before and during cyproterone-acetate treatment. To confirm the diagnosis of precocious puberty the hormonal pattern of LH, FSH and prolactin were determined at 1800 h, 2200 h, 0200 h and 0800 h, as well as the responsiveness 30 min after a LRH/TRH stimulation. Basal plasma FSH levels were elevated in comparison to those found in control females with a comparable degree of sexual maturation. In comparison, an increased gonadotropin release at sleep was found in all three girls, whereas the nocturnal increase of plasma prolactin was nearly similar to control females. An excessive gonadotropin response to LRH stimulation was demonstrable in all three girls. Plasma prolactin response to TRH was comparable to control females.

Cyproterone-acetate (CA) was administered in a dosage of 150 mg/m². During CA treatment, basal plasma LH levels were depressed to subnormal values without any signs of a nocturnal hormone rhythm. Basal plasma FSH levels were also reduced although a nocturnal increase was still existent being lower than in control females. Basal plasma prolactin levels, however, increased three- to fivefold without increasing hormone values at night. The response of elevated basal prolactin levels to TRH stimulation was minimal.

These results suggest that the hormonal pattern in girls with premature thelarche and advanced bone age are comparable to those found in girls with precocious puberty. Therefore, these patients should also be classified as “idiopathic precocious puberty”. It may be hypothesized that CA operates at hypothalamic and/or pituitary levels in stimulating prolactin release.

Key-Words

Premature Thelarche - Precocious Puberty - Cyproterone-Acetate - Hyperprolactinaemia