We propose a mean lysine requirement of 30 mg x kg(-1) x d(-1) for healthy Indian adults, which is the same amount we proposed previously for Western populations.

The international 1985 FAO/WHO/UNU upper dietary requirement for lysine of 12 mg.kg-1.d-1 may be inadequate for healthy Indian adults. To test this, we used a modified indicator amino acid oxidation technique to assess the adequacy of lysine intake of 12 and 28 mg.kg-1.d-1. Seven healthy, male, Indian subjects were studied during each of two randomly assigned 6-d periods while receiving an otherwise adequate diet based on an L-amino acid mixture. Beginning at 1800 on day 6 of the diet, a 24-h infusion protocol in which a [13C]leucine tracer was administered intravenously was used to assess leucine oxidation and daily leucine balance at each test lysine intake. Mean 24-h leucine oxidation was 54.7 compared with 46.9 mg.kg-1.d-1 (P < 0.05) and mean 24-h leucine balances were -4.1 and 3.5 mg.kg-1.d-1 (P < 0.05) for lysine intakes of 12 and 28 mg, respectively. Leucine balances were significantly negative (0.025 < P < 0.05) with the 12-mg lysine intake and not significantly different (P > 0.10) from zero or equilibrium with the 28-mg intake. These findings indicate that the international requirement for lysine appears to be inadequate to maintain body amino acid homeostasis and function in apparently healthy subjects characteristic of the south Asia region. They further indicate that our previously proposed, tentative lysine requirement of 30 mg.kg-1.d-1 is probably adequate for this population.

Context The management of youth with delayed puberty is hampered by difficulty in predicting who will eventually progress through puberty and who will fail to attain adult reproductive endocrine function. The neuropeptide kisspeptin, which stimulates gonadotropin-releasing hormone (GnRH) release, can be used to probe the integrity of the reproductive endocrine axis. Objective We sought to determine whether responses to kisspeptin can predict outcomes for individuals with pubertal delay. Design, Setting, and Participants We conducted a longitudinal cohort study in an academic medical center of 16 children (3 girls and 13 boys) with delayed or stalled puberty. Intervention and Outcome Measures Children who had undergone kisspeptin- and GnRH-stimulation tests were followed every 6 months for clinical evidence of progression through puberty. Inhibin B was measured in boys. A subset of participants underwent exome sequencing. Results All participants who had responded to kisspeptin with a rise in luteinizing hormone (LH) of 0.8 mIU/mL or greater subsequently progressed through puberty (n = 8). In contrast, all participants who had exhibited LH responses to kisspeptin ≤ 0.4 mIU/mL reached age 18 years without developing physical signs of puberty (n = 8). Thus, responses to kisspeptin accurately predicted later pubertal outcomes (P = .0002). Moreover, the kisspeptin-stimulation test outperformed GnRH-stimulated LH, inhibin B, and genetic testing in predicting pubertal outcomes. Conclusion The kisspeptin-stimulation can assess future reproductive endocrine potential in prepubertal children and is a promising novel tool for predicting pubertal outcomes for children with delayed puberty.

The prognosis of pediatric adrenocortical carcinoma often depends on prompt diagnosis to begin treatment before metastatic progression. We discuss a girl who presented at 8 months of age with virilization, which was thought to be due to exposure to a topical testosterone preparation being used by her father. Her testosterone level did not decrease promptly after her father discontinued the medication, however, and when she followed up with signs of Cushing syndrome 5 months later, metastatic adrenocortical carcinoma was diagnosed. The patient was successfully treated with surgery and multiagent chemotherapy. Nine months after the end of treatment, her testosterone level was again found to be elevated. Testosterone precursors were now absent, however, and there were no imaging signs of recurrence. Further history showed that her father had restarted topical testosterone, and this time, exogenous exposure was correctly diagnosed. As use of topical testosterone becomes more prevalent, exogenous exposure must be considered in the differential diagnosis of childhood virilization. Any persistent testosterone elevation after exposure ceases or signs of hypercortisolism, however, are inconsistent with this diagnosis. We believe that the risk-benefit ratio favors abdominal ultrasound to rule out malignancy in all children presenting with virilization.