Puberty is the transitional period from childhood to adulthood. At puberty onset, a change in the set point (sensitivity) of the so-called ”gonadostat”, which is located in the hypothalamus, occurs. During childhood, small amounts of sex hormones produced in steroid hormone secreting and metabolizing organs suppress the activity in those central regions of the brain (hypothalamus and pituitary), which then, at puberty onset, begin to control the puberty-characteristic sex steroid changes. While the exact underlying mechanism for the changed set-point (i.e., the decreased hypothalamic sensitivity to the initially low childhood sex steroid levels) are unknown, the consequences are clear: in boys, the increased secretion of luteinizing hormone stimulates the testosterone production in the testicles; in girls, the ovarian production of oestrogens is stimulated. The effect of the sex hormones is further enhanced by a decrease in binding proteins, thereby allowing for higher levels of unbound sex steroids. In general, puberty starts earlier in girls than in boys. Direct consequences of the pubertal hormonal alterations are changes in secondary sex characteristics. These changes are used as markers of puberty onset or puberty development.
The importance of the changes in pubertal development and the age at puberty onset is on the one hand based on medical complications later in life, e.g. an increased risk of breast cancer, arthritis, adiposity, impaired glucose tolerance or depression with early menarche. On the other hand, psycho-social problems may arise if sexual maturation precedes the mental and personal maturation of the teenagers.
In order to test the relevant hypotheses regarding the potential influence of life-style and physiological factors on pubertal timing, and to evaluate the related research questions, detailed data from a longitudinal cohort of children and adolescents have to be examined for the identification of potential cause-effect relationships. Cross-sectional studies are inappropriate to analyze time-dependent causal and non-causal factors.
Lijie Shia, Christiane Maser-Gluthb, Thomas Remera (2008) Daily urinary free cortisol and cortisone excretion is associated with urine volume in healthy children. Steroids. 73, 1446-1451
Shi L., Wudy A. S., Buyken E.A., Hartmann F.M. and Remer T. (2009). Body fat and animal protein intakes are associated with adrenal androgen secretion in children. The American Journal of Clinical Nutrition. 90, 1321-8.
Remer T. et al. (2009). Prepubertal Healthy Children's Urinary Androstenediol Predicts Diaphyseal Bone Strength in Late Puberty. The Journal of Clinical Endoc
Remer T., Shi L., Buyken A.E., Maser-Gluth C., Hartmann M.F. and Wudy S.A. (2010). Prepubertal Adrenarchal Androgens and Animal Protein Intake Independently and Differentially Influence Pubertal Timing. The Journal of Clinical Endocrinology & Metabolism. 95(6), 3002-3009.
Gisela H. Degen, Meinolf Blaszkewicz, Lijie Shi, Anette E. Buyken and Thomas Remer (2010) Urinary isoflavone phytoestrogens in German children and adolescents - A longitudinal examination in the DONALD cohort. Mol. Nutr. Food Res. 2011, 55, 359-367
Lijie Shi, Thomas Remer, Anette E. Buyken, Michaela F. Hartmann, Philipp Hoffmann, and Stefan A. Wudy Prepubertal urinary estrogen excretion and its relationship with pubertal timing. Am J Physiol Endocrinol Metab 299, E990-E997.
Cheng et al. (2010). Relation of isoflavones and fiber intake in childhood to the timing of puberty. The American Journal of Clinical Nutrition. 92(3), 556-64.
Adrenarchal androgens, prepubertal macronutrient intake, and pubertal timing by L. Shi, S.A. Wudy, A.E. Buyken, M.F. Hartmann and T. Remer
Relation of isoflavones and fiber intake in childhood to the timing of puberty by G. Cheng, T. Remer, M. Blaszkewicz, G.H. Degen and A.E. Buyken
A novel stable isotope dilution / benchtop gas chromatography - mass spectrometry (ID/GC-MS) assay for profiling estrogens, their biologically active metabolites and testosterone in human urine by P. Hoffmann, M.F. Hartmann, T. Remer, K.P. Zimmer and S.A. Wudy
Renal excretion rates of free cortisol, free cortisone and dehydroepiandrosterone metabolites, but not renal indices of cortisol secretion are associated with urinary volume in healthy children by Lijie Shi, Stefan A. Wudy, Christiane Maser-Gluth, Michaela F. Hartmann and Thomas Remer