Testosterone exposure in childhood: discerning pathology from physiology

The co-expression of steroidogenic enzymes with T1R3 during testicular development in the Congjiang Xiang pig

Testosterone is a key crucial hormone synthesized by steroidogenic enzymes that initiate and maintain spermatogenesis and secondary sexual characteristics in adult males. The taste receptor family 1 subunit 3 (T1R3) is reported to be associated with male reproduction. T1R3 can regulate the expressions of steroidogenic enzymes and affect testosterone synthesis. In this study, we addressed the question of whether the expression of steroid synthase was associated with T1R3 and its downstream-tasting molecules during testicular development. The results showed an overall upward trend in testosterone and morphological development in testes from Congjiang Xiang pigs from pre-puberty to sexual maturity. Gene expression levels of testicular steroidogenic acute regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), cytochrome P450c17 (CYP17A1) and 17β-hydroxysteroid dehydrogenase (17β-HSD) were increased from pre-puberty to sexual maturity. Protein expression changes of CYP17A1 and 3β-HSD were consistent with mRNA. The relative abundance of tasting molecules (TAS1R3, phospholipase Cβ2, PLCβ2) was increased from pre-puberty to puberty (P < 0.05), with no further significant changes in expression from puberty to sexual maturity. Steroidogenic enzymes (3β-HSD and CYP17A1) were strongly detected in Leydig cells from pre-puberty to sexual maturity, while tasting molecules were localized in Leydig cells and spermatogenic cells. Correlation analysis showed that the genes mentioned above (except for PLCβ2) were positively correlated with testosterone levels and morphological characteristics of the testes at different developmental stages of Congjiang Xiang pigs. These results suggest that steroidogenic enzymes regulate testosterone synthesis and testicular development, and that taste receptor T1R3, but not PLCβ2, may associate with this process.

Update on adrenarche

PURPOSE OF REVIEW

Adrenarche is the pubertal maturation of the innermost zone of the adrenal cortex, the zona reticularis. The onset of adrenarche occurs between 6 and 8 years of age when dehydroepiandrosterone sulfate (DHEAS) concentrations increase. This review provides an update on adrenal steroidogenesis and the differential diagnosis of premature development of pubic hair.

RECENT FINDINGS

The complexity of adrenal steroidogenesis has increased with recognition of the alternative 'backdoor pathway' and the 11-oxo-androgens pathways. Traditionally, sulfated steroids such as DHEAS have been considered to be inactive metabolites. Recent data suggest that intracellular sulfated steroids may function as tissue-specific intracrine hormones particularly in the tissues expressing steroid sulfatases such as ovaries, testes, and placenta.

SUMMARY

The physiologic mechanisms governing the onset of adrenarche remain unclear. To date, no validated regulatory feedback mechanism has been identified for adrenal C19 steroid secretion. Available data indicate that for most children, premature adrenarche is a benign variation of development and a diagnosis of exclusion. Patients with premature adrenarche tend to have higher BMI values. Yet, despite greater knowledge about C19 steroids and zona reticularis function, much remains to be learned about adrenarche.

Androgens During Infancy, Childhood, and Adolescence: Physiology and Use in Clinical Practice

We provide an in-depth review of the role of androgens in male maturation and development, from the fetal stage through adolescence into emerging adulthood, and discuss the treatment of disorders of androgen production throughout these time periods. Testosterone, the primary androgen produced by males, has both anabolic and androgenic effects. Androgen exposure induces virilization and anabolic body composition changes during fetal development, influences growth and virilization during infancy, and stimulates development of secondary sexual characteristics, growth acceleration, bone mass accrual, and alterations of body composition during puberty. Disorders of androgen production may be subdivided into hypo- or hypergonadotropic hypogonadism. Hypogonadotropic hypogonadism may be either congenital or acquired (resulting from cranial radiation, trauma, or less common causes). Hypergonadotropic hypogonadism occurs in males with Klinefelter syndrome and may occur in response to pelvic radiation, certain chemotherapeutic agents, and less common causes. These disorders all require testosterone replacement therapy during pubertal maturation and many require lifelong replacement. Androgen (or gonadotropin) therapy is clearly beneficial in those with persistent hypogonadism and self-limited delayed puberty and is now widely used in transgender male adolescents. With more widespread use and newer formulations approved for adults, data from long-term randomized placebo-controlled trials are needed to enable pediatricians to identify the optimal age of initiation, route of administration, and dosing frequency to address the unique needs of their patients.

Blood metal levels and serum testosterone concentrations in male and female children and adolescents: NHANES 2011-2012

Environmental exposure to metals is ubiquitous, but its relation to androgen hormone levels is not well understood, especially in children and adolescents. This study aimed to explore the relationship between blood metal concentrations (lead, cadmium, total mercury, selenium, and manganese) and serum total testosterone (TT) levels in 6–19-year-old children and adolescents in the National Health and Nutrition Examination Survey (NHANES) 2011–2012. Weighted multivariable linear regression models using NHANES sampling weights were employed to evaluate the association between log-transformed serum TT and each metal categories in male and female children (age 6-11years) and adolescents (age 12–19 years). We established that blood cadmium and manganese levels were associated with significantly higher serum TT levels in the female adolescents. Additionally, the blood selenium levels in male adolescents were related to significantly higher serum TT. No significant associations between blood lead or total mercury levels and TT were observed in children or adolescents of either sex. These findings suggest that environmental exposure to certain metals could affect serum TT levels in adolescents, which might have important implications for the health of adolescents. Further research is required to confirm and extend our present findings.

Update on Precocious Puberty in Girls

Precocious puberty (PP) in girls refers to secondary sexual development occurring earlier than the lower end of normal for the onset of puberty. It might be the presenting feature of a serious underlying condition or signify a common variation of normal for which no treatment is necessary. Depending on the source and type of sex steroids involved, clinical findings may indicate exposure to estrogens, androgens, or both. Likewise, the onset of the PP might be gradual or abrupt and the rate of progression is variable. Recent years have witnessed exciting advancements in the understanding of the molecular genetic basis for some forms of PP in girls as well as in the development of additional treatment options. In this review an update on the most commonly encountered causes of PP in girls including their clinical presentation, pathophysiology, diagnosis, and management are provided. Recommendations regarding when to refer, and areas in particular need of additional research are also delineated.

Rhinencephalon changes in tuberous sclerosis complex

PURPOSE

Despite complex olfactory bulb embryogenesis, its development abnormalities in tuberous sclerosis complex (TSC) have been poorly investigated.

METHODS

Brain MRIs of 110 TSC patients (mean age 11.5 years; age range 0.5-38 years; 52 female; 26 TSC1, 68 TSC2, 8 without mutation identified in TSC1 or TSC2, 8 not tested) were retrospectively evaluated. Signal and morphological abnormalities consistent with olfactory bulb hypo/aplasia or with olfactory bulb hamartomas were recorded. Cortical tuber number was visually assessed and a neurological severity score was obtained. Patients with and without rhinencephalon abnormalities were compared using appropriate parametric and non-parametric tests.

RESULTS

Eight of110 (7.2%) TSC patients presented rhinencephalon MRI changes encompassing olfactory bulb bilateral aplasia (2/110), bilateral hypoplasia (2/110), unilateral hypoplasia (1/110), unilateral hamartoma (2/110), and bilateral hamartomas (1/110); olfactory bulb hypo/aplasia always displayed ipsilateral olfactory sulcus hypoplasia, while no TSC patient harboring rhinencephalon hamartomas had concomitant forebrain sulcation abnormalities. None of the patients showed overt olfactory deficits or hypogonadism, though young age and poor compliance hampered a proper evaluation in most cases. TSC patients with rhinencephalon changes had more cortical tubers (47 ± 29.1 vs 26.2 ± 19.6; p = 0.006) but did not differ for clinical severity (p = 0.45) compared to the other patients of the sample.

CONCLUSIONS

Olfactory bulb and/or forebrain changes are not rare among TSC subjects. Future studies investigating clinical consequences in older subjects (anosmia, gonadic development etc.) will define whether rhinencephalon changes are simply an imaging feature among the constellation of TSC-related brain changes or a feature to be searched for possible implications in the management of TSC subjects.

Premature Adrenarche

Adrenarche is when a child's adrenal cortex starts to secrete adrenal androgen precursors. Dehydroepiandrosterone (DHEA) is the most abundant product of the adrenal cortex, and is a weak androgen agonist thought to be responsible for the clinical signs of pubarche by conversion to more potent androgens, testosterone, and dihydrotestosterone. DHEA's extra-adrenal sulfation product, dehydroepiandrosterone sulfate, is a stable marker for adrenal androgenic activity. Pubarche is the physical manifestation of androgenic hormone production, and includes the development of pubic and axillary hair, adult body odor, and acne. This stage is usually considered premature if it commences before age 8 years in girls or age 9 years in boys. Premature adrenarche is a diagnosis of exclusion, as true centrally mediated precocious puberty, congenital adrenal hyperplasia, exogenous androgen exposure, and androgen-secreting tumors must be ruled out. Premature adrenarche may be associated with a history of an infant who was small for gestational age at birth who then gained weight rapidly thereafter or became obese. In some instances, premature adrenarche may predict functional ovarian hyperandrogenism in adolescence. Management of premature adrenarche is largely aimed at observation, lifestyle adjustments for weight concerns, and monitoring for future possible persistent androgen excess and insulin resistance. [Pediatr Ann. 2018;47(1):e7-e11.].

Natesto™ , a novel testosterone nasal gel, normalizes androgen levels in hypogonadal men

Advantages of testosterone nasal gel include ease of administration, low dose, and no risk of secondary transference. The efficacy and safety of testosterone nasal gel was evaluated in hypogonadal males. The ninety-day, randomized, open-label, dose-ranging study, included potential dose titration and sequential safety extensions to 1 year. At 39 US outpatient sites, 306 men (mean age 54.4 years) with two fasting morning total serum testosterone levels <300 ng/dL were randomized (n = 228, b.i.d. dosing; n = 78, t.i.d. dosing). Natesto(™) Testosterone Nasal Gel was self-administered, using a multiple-dose dispenser, as two or three daily doses (5.5 mg per nostril, 11.0 mg single dose). Total daily doses were 22 mg or 33 mg. The primary endpoint was the Percentage of patients with Day-90 serum total testosterone average concentration (C(avg)) value within the eugonadal range (≥300 ng/dL, ≤1050 ng/dL). At Day 90, 200/273 subjects (73%; 95% CI 68, 79) in the intent-to-treat (ITT) population and 180/237 subjects (76%; 71, 81) in the per-protocol (PP) population were in the normal range. Also, in the normal range were 68% (61, 74) of ITT subjects and 70% (63, 77) of PP subjects in the titration arm, as well as, 90% (83, 97) of ITT subjects and 91% (84, 98) of PP subjects in the fixed-dose arm. Natesto(™) 11 mg b.i.d. or 11 mg t.i.d. restores normal serum total testosterone levels in most hypogonadal men. Erectile function, mood, body composition, and bone mineral density improved from baseline. Treatment was well tolerated; adverse event rates were low. Adverse event discontinuation rates were 2.1% (b.i.d.) and 3.7% (t.i.d.). This study lacked a placebo or an active comparator control which limited the ability to adequately assess some measures.