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- ACTH Adrenocorticotropin
- AZF Azoospermia factor
- cAMP Cyclic adenosine monophosphate
- DHEA Dehydroepiandrosterone
- DHEAS Dehydroepiandrosterone sulfate
- FSH Follicle-stimulating hormone
- GH Growth hormone
- GnRH Gonadotropin-releasing hormone
- hCG Human chorionic gonadotropin
- HESX-1 Hesx-1 homeodomain
- HDL High-density lipoprotein
- HPLC MS/MS High performance liquid chromatography tandem mass spectroscopy
- hGH Human growth hormone
- ICMA Immunochemiluminometric assay
- IGF-1 Insulin-like growth factor 1
- KAL1 Kallmann syndrome
- LDL Low-density lipoprotein
- LH Luteinizing hormone
- LHX3 LIM homeobox gene 3
- PROP-1 Prophet of PIT 1
- PROK1 Prokineticin receptor 2
- PRL Prolactin
- PSA Prostate-specific antigen
- SHBG Sex hormone–binding globulin
- SF-1 Steroidogenic factor 1
- SHOX Short stature homeobox
- SRIF Somatostatin
- TGF-α Transforming growth factor alpha
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Puberty is best considered as one stage in the continuing process of growth and development that begins during gestation and continues until the end of reproductive life. After an interval of childhood quiescence—the juvenile pause—the hypothalamic pulse generator increases activity in the peripubertal period, just before the physical changes of puberty commence. This leads to increased secretion of pituitary gonadotropins and, subsequently, gonadal sex steroids that bring about secondary sexual development, the pubertal growth spurt, and fertility. Historical records show that the age at onset of particular stages of puberty in boys and girls in Western countries has steadily declined over the last several hundred years; this is probably due to improvements in socioeconomic conditions, nutrition, and, therefore, the general state of health during that period. This trend appears to be continuing but now due more to the effects of the obesity epidemic than the improvement in general health.
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Many endogenous and exogenous factors can alter age at onset of puberty. While obesity may decrease the age of onset of puberty, chronic illness and malnutrition often delay puberty. There is a significant concordance of age at menarche between mother-daughter pairs and within ethnic populations, indicating the influence of genetic factors. Recent study of genetic loci associated with the age of onset of puberty suggests the existence of several genes that are likely involved in the regulation of menarche and puberty.
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Physical Changes Associated with Puberty
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Descriptive standards proposed by Tanner for assessing pubertal development in males and females are in wide use (denoted as Sexual Maturation stages or, often, Tanner stages). They focus attention on specific details of the examination and make it possible to objectively record subtle progression of secondary sexual development that may otherwise be overlooked. Self-assessment of pubertal development by subjects using reference pictures is used in clinical studies but reliability is less than that achieved by physical examination.
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The first sign of puberty in the female, as noted in longitudinal studies, is an increase in height velocity that heralds the beginning of the pubertal growth spurt; girls are not usually examined frequently enough to demonstrate this change in clinical practice, so breast development is the first sign of puberty noted by most examiners. Breast development (Figure ...