Related Experiment Video

Updated: Jul 16, 2026

Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies
06:24

Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies

Published on: January 10, 2025

Thyroid outcome during long-term gonadotropin-releasing hormone agonist treatments for idiopathic precocious puberty

Francesco Massart1, Joshua Chuck Harrell, Giovanni Federico

  • 1Pediatric Endocrine Center/Department of Pediatrics, University of Pisa, Pisa, Italy. massart@med.unipi.it

The Journal of Adolescent Health : Official Publication of the Society for Adolescent Medicine
|February 27, 2007
PubMed

Insights

Long-term gonadotropin-releasing hormone agonist (GnRHa) treatment for central precocious puberty (CPP) in girls showed no thyroid dysfunction. Thyroid hormone levels changed, but monitoring is not required.

Area of Science:

  • Pediatric Endocrinology
  • Reproductive Endocrinology
  • Thyroidology

Background:

  • Central precocious puberty (CPP) is a condition where puberty begins unusually early.
  • Gonadotropin-releasing hormone agonists (GnRHa) are used to suppress puberty in children with CPP.
  • The long-term effects of GnRHa on thyroid function require further investigation.

Purpose of the Study:

  • To assess the impact of long-term GnRHa administration on thyroid hormone levels in girls with idiopathic CPP.
  • To compare the effects of two different GnRHa formulations, leuprorelin acetate (LA) and triptorelin (TR), on thyroid function.

Main Methods:

  • A retrospective study of 73 girls with idiopathic CPP treated with GnRHa (LA or TR).
  • Thyroid hormones (TSH, FT3, FT4) and antibodies were measured at baseline and over 40 months of treatment.
  • Statistical analysis was performed to compare hormone levels between treatment groups and over time.

Main Results:

  • Free triiodothyronine (FT3) levels significantly declined during both LA and TR treatments.
  • The FT3/thyroxine (FT4) ratio showed significant differences between the LA and TR groups.
  • Thyroid-stimulating hormone (TSH) secretion was not affected overall, but LA induced lower TSH values than TR.

Conclusions:

  • Long-term GnRHa treatment for CPP in girls does not lead to evidence of thyroid dysfunction.
  • While changes in TSH, FT3, and FT3/FT4 ratios were observed, they do not necessitate routine thyroid monitoring.
  • The study suggests that thyroid activity monitoring is not required during GnRHa administration for CPP.
Abstract

Related Concept Videos

Synthesis and Regulation of Thyroid Hormones01:20

Synthesis and Regulation of Thyroid Hormones

Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the thyrotropin-releasing hormone (TRH). TRH then reaches the pituitary gland and stimulates the release of thyroid-stimulating hormone(TSH) into the bloodstream.
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Hyperthyroidism I: Introduction01:25

Hyperthyroidism I: Introduction

Hyperthyroidism is a type of thyrotoxicosis characterized by the thyroid gland's overproduction of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). This hormone excess increases the basal metabolic rate and enhances sensitivity to catecholamines.DiagnosisDiagnosis is based on clinical features and biochemical testing. It typically shows suppressed thyroid-stimulating hormone (TSH) levels below 0.4 mIU/L, with elevated free T3 and/or T4. Additional tests, including thyroid...
Functions of Thyroid Hormones01:18

Functions of Thyroid Hormones

The thyroid hormone (TH) plays a pivotal role in the intricate orchestration of physiological processes, exerting profound effects on development, metabolism, and homeostasis throughout different life stages.
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
Signs of Puberty01:27

Signs of Puberty

Puberty is a critical phase, typically beginning between the ages of 8 and 13 in girls and 9 and 14 in boys, though timing can vary based on genetics, environmental factors, and overall health. This period is characterized by the development of secondary sexual characteristics and the attainment of reproductive potential. Endocrine changes underpin puberty, with hormonal surges of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) instigated by Gonadotropin-Releasing Hormone (GnRH)...
Hyperthyroidism II: Pathophysiology01:27

Hyperthyroidism II: Pathophysiology

Hyperthyroidism is a hypermetabolic state caused by elevated levels of thyroid hormones, triiodothyronine (T3) and thyroxine (T4). It results from dysregulation at the thyroid, pituitary, or immune system level and affects multiple organ systems.PathophysiologyThe most common cause of hyperthyroidism is Graves’ disease, an autoimmune disorder in which antibodies, specifically thyroid-stimulating antibodies (TSAb), a subtype of TSH receptor antibodies (TRAb), bind to and activate TSH receptors...
Goiter01:27

Goiter

Goiter refers to an abnormal enlargement of the thyroid gland that may appear as a diffuse goiter (uniform enlargement) or nodular (single or multiple nodules). Functionally, it is classified as nontoxic (normal/low hormone levels) or toxic (excess hormone production).PathophysiologyDiffuse thyroid enlargement typically results from prolonged stimulation by thyroid-stimulating hormone (TSH) or TSH-like agents, commonly seen in hypothyroidism or iodine deficiency. In contrast, in hyperthyroid...