Familial precocious puberty associated with isolated elevation of luteinizing hormone

Normal and Premature Adrenarche

Adrenarche is the maturational increase in adrenal androgen production that normally begins in early childhood. It results from changes in the secretory response to adrenocorticotropin (ACTH) that are best indexed by dehydroepiandrosterone sulfate (DHEAS) rise. These changes are related to the development of the zona reticularis (ZR) and its unique gene/enzyme expression pattern of low 3ß-hydroxysteroid dehydrogenase type 2 with high cytochrome b5A, sulfotransferase 2A1, and 17ß-hydroxysteroid dehydrogenase type 5. Recently 11-ketotestosterone was identified as an important bioactive adrenarchal androgen. Birth weight, body growth, obesity, and prolactin are related to ZR development. Adrenarchal androgens normally contribute to the onset of sexual pubic hair (pubarche) and sebaceous and apocrine gland development. Premature adrenarche causes ≥90% of premature pubarche (PP). Its cause is unknown. Affected children have a significantly increased growth rate with proportionate bone age advancement that typically does not compromise growth potential. Serum DHEAS and testosterone levels increase to levels normal for early female puberty. It is associated with mildly increased risks for obesity, insulin resistance, and possibly mood disorder and polycystic ovary syndrome. Between 5% and 10% of PP is due to virilizing disorders, which are usually characterized by more rapid advancement of pubarche and compromise of adult height potential than premature adrenarche. Most cases are due to nonclassic congenital adrenal hyperplasia. Algorithms are presented for the differential diagnosis of PP. This review highlights recent advances in molecular genetic and developmental biologic understanding of ZR development and insights into adrenarche emanating from mass spectrometric steroid assays.

Endocrine antecedents of polycystic ovary syndrome in fetal and infant prenatally androgenized female rhesus monkeys

Experimentally induced fetal androgen excess induces polycystic ovary syndrome-like traits in adult female rhesus monkeys (Macaca mulatta). Developmental changes leading to this endocrinopathy are not known. We therefore studied 15 time-mated, gravid female rhesus monkeys with known female fetuses. Nine dams received daily s.c. injections of 15 mg of testosterone propionate (TP), and six received injections of oil vehicle (control) from 40 through 80 days of gestation (term, 165 days; range, +/-10 days). All fetuses were delivered by cesarean section using established methods at term. Ultrasound-guided fetal blood sample collection and peripheral venous sample collection of dams and subsequent infants enabled determination of circulating levels of steroid hormones, LH and FSH. The TP injections elevated serum testosterone and androstenedione levels in the dams and prenatally androgenized (PA) fetuses. After cessation of TP injections, testosterone levels returned to values within the reference range for animals in these age groups, whereas serum androstenedione levels in PA infants were elevated. The TP injections did not increase estrogen levels in the dams or the PA fetuses or infants, yet conjugated estrogen levels were elevated in the TP-injected dams. Serum levels of LH and FSH were elevated in late-gestation PA fetuses, and LH levels were elevated in PA infants. These studies suggest that experimentally induced fetal androgen excess increases gonadotropin secretion in PA female fetuses and infants and elevates endogenous androgen levels in PA infants. Thus, in this nonhuman primate model, differential programming of the fetal hypothalamo-pituitary unit with concomitant hyperandrogenism provides evidence to suggest developmental origins of LH and androgen excess in adulthood.

Intrauterine growth retardation and early adolescent growth spurt in two sisters

Two sisters who presented with a similar growth pattern are described. They delivered with idiopathic intrauterine growth retardation and had an early adolescent growth spurt. The physical and endocrine findings suggested a potential relationship between intrauterine growth retardation and early puberty.

Puberty without gonadotropins. A unique mechanism of sexual development

Recent evidence suggests that a group of children exists in whom premature sexual maturation occurs in the absence of pubertal levels of gonadotropins; that is, they have gonadotropin-independent precocious puberty. We compared six boys and one girl with this disorder with four boys and five girls with central precocious puberty, in which there is a pubertal pattern of gonadotropin release. The two groups were similar in age of onset, degree of sexual development, growth velocity, and rate of skeletal maturation. A family history of precocity was noted in four of the boys with gonadotropin-independent precocity, and the girl had McCune-Albright syndrome. Children with central precocious puberty demonstrated a pulsatile release of gonadotropins, pubertal responses to luteinizing hormone-releasing hormone, and complete suppression of gonadarche after exposure to an analogue of luteinizing hormone-releasing hormone (LHRHa). In contrast, children with gonadotropin-independent precocity demonstrated an absence of gonadotropin pulsations, variable responses to luteinizing hormone-releasing hormone, lack of suppression of puberty in response to LHRHa, and cyclic steroidogenesis. Tissue from testicular biopsies performed in five of six boys with gonadotropin-independent precocity showed a range from incipient pubertal development of the tubules with proliferation of Leydig cells to the appearance of normal adult testes. We conclude that gonadotropin-independent precocious puberty is a distinct syndrome, of unknown cause, that may be familial and may have been responsible for many previously reported cases of precocious puberty.

Pubertal development: normal, precocious and delayed

The present concepts on the neuroendocrine mechanisms which trigger pubertal development and modulate the progression towards sexual maturity have been reviewed. Essentially, puberty is presented as a continuum, the programming of which is initiated prenatally and which ends in adult life when all hormonal secretions become autoregulated. This continuum is dependent on a delicate equilibrium between CNS neurohormones (GnRH), neurotransmitters (biogenic amines), pituitary gonadotrophin (FSH, LH) secretion and the end-organ response (testis or ovary) through the activation of specific membrane receptors. The gonadal sex steroids (T, OE2) will activate specific cytoplasmic and nuclear receptors of target tissues and exert their biological action. Initially, the activity of the HPGA is manifested by nocturnal LH peaks, followed by increased gonadal secretion of T or OE2. Extremely sensitive to negative feedback by circulating androgen and/or oestrogen in prepuberty, an hypothalamic regulatory system called the gonadostat increases its threshold of sensitivity and eventually becomes autoregulated at a higher feedback level. Progressively, the hypothalamus becomes sensitive to positive feedback action of gonadal hormones, this phenomenon being important for the onset of ovulation. It is likely also that adrenal androgens play a permissive and supportive role in the onset and progression of pubertal development. Finally, full maturity is reached, with final adult height through fusion of the epiphysis, and fertility is achieved. The clinical manifestations of each developmental stage of puberty are described and abnormalities of sexual development reviewed. While over 90 per cent of cases of precocious pubertal development are idiopathic in girls, a space-occupying lesion in the hypothalamic-pituitary region is frequent in boys. Dissociated pubertal signs (premature adrenarche, pubarche, thelarche, menarche) are discussed, together with diagnosis and treatment of precocious puberty, whether it is idiopathic or occurring independently of the activation of the HPGA. In addition to delay of puberty on a constitutional basis, or related to chronic endocrine or non-endocrine diseases, the main clinical entities with gonadal insufficiency, primary (hypergonadotrophic) or secondary (hypogonadotrophic), are reviewed in boys and girls and their investigation and treatment discussed.