[Growth hormone, insulin, IGF-1 and estradiol levels during maturation of internal sex organs before and at menarche].

INTRODUCTION

The growth hormone (GH) is the main activator of growth, exerting its biological effects through IGF-1 and IGF-2 growth factors. Secretion of GH is partly controlled by steroid sex hormones.

MATERIAL AND METHODS

Body mass, height, BMI, and body composition were recorded every three months in 45 healthy girls 8 years of age. Tertiary sex features according to Tanner were determined. Transabdominal ultrasound of the uterus and ovaries was done. GH, insulin, and IGF-1 levels in serum were measured radioimmunologically with commercial test kits. E2 levels were determined with an immunoenzymatic method.

RESULTS

GH levels increased until stage M3 of breast maturation and gradually decreased during stage M4 (12 girls with menarche). IGF-1 and insulin levels continued to increase until stage M4. Uterine and ovarian dimensions correlated with levels of hormones studied.

CONCLUSION

High levels of GH and IGF-1 during the early and central stages of puberty seem to affect the maturation of internal sex organs.