Increased melatonin concentrations in children with growth hormone deficiency

Effect of Germination and Illumination on Melatonin and Its Metabolites, Phenolic Content, and Antioxidant Activity in Mung Bean Sprouts

Mung bean (Vigna radiata L.) sprouts are increasingly consumed and have become part of a healthy diet. The sprouts are composed of proteins, carbohydrates, and biochemical compounds. During germination, the phytochemical compounds are significantly elevated, especially under stress conditions such as salinity, drought, extreme temperature, and illumination. The present study examined the effects of light and germination time on the bioactive compounds in mung bean sprout extracts. Mung bean seeds were sprouted under different light exposure conditions, and the phytochemical composition and antioxidant activity of sprout extracts were determined compared to seeds. The results show that tryptophan sharply decreased during germination. On the contrary, melatonin, polyphenols, and total phenolic content (TPC) were elevated with increased germination time, correlated with increased antioxidant activity. Sprouts germinated in the dark presented higher levels of melatonin and TPC compared with those germinated under 12 h light exposure (3.6- and 1.5-fold, respectively). In conclusion, germination can enhance valuable phytochemicals and antioxidant activity of mung bean sprouts. Mung bean sprouts may be a good alternative functional food for promoting human health.

Decreased 6-Sulfatoxymelatonin Excretion in Male GH-Deficient Children and Adolescents

AIM

To evaluate melatonin secretion in a group of untreated and treated male growth hormone (GH)-deficient children and adolescents.

METHODS

We studied 44 male subjects: 8 untreated GH-deficient patients (GHDnt), 16 treated GH-deficient patients (GHDt) and 20 healthy children and adolescents as control group (CG). We measured urinary 6-sulfatoxymelatonin (6-SM) in total (24-hour samples), nocturnal (18.00-8.00 h) and diurnal samples (8.00-18.00 h). Levels of 6-SM were expressed as micrograms excreted per time interval and x0394; values (difference between nighttime and daytime values).

RESULTS

Significant differences were observed among the 3 groups of pediatric subjects studied for total 6-SM (p < 0.0001), nocturnal 6-SM (p < 0.0001) and x0394; values (p < 0.0001). Subsequent analysis showed significantly higher levels for total 6-SM, nocturnal 6-SM and nighttime-daytime x0394; in the CG versus the GHDnt (p < 0.01) and in the CG versus the GHDt group (p < 0.01). No significant correlations were found between 6-SM excretion and insulin-like growth factor-1 values in the children and adolescents studied.

CONCLUSIONS

GH-deficient patients showed lower levels of 6-SM. Our findings provide a different insight to a further understanding of some chronobiological disorders involved in GH deficiency in children.

Alterations in diurnal rhythmicity in patients treated for nonfunctioning pituitary macroadenoma: a controlled study and literature review

OBJECTIVE

Patients treated for nonfunctioning pituitary macroadenomas (NFMAs) have fatigue and alterations in sleep characteristics and sleep-wake rhythmicity frequently. As NFMAs often compress the optic chiasm, these complaints might be related to dysfunction of the adjacent suprachiasmatic nucleus (SCN). We aimed to explore whether indirect indices of SCN functioning are altered in the long term after surgery for NFMAs.

METHODS

We studied 17 NFMA patients in long-term remission after transsphenoidal surgery, receiving adequate and stable hormone replacement for hypopituitarism, and 17 control subjects matched for age, gender, and BMI. Indirect indices of SCN function were assessed from 24-h ambulatory recordings of skin and core body temperatures, blood pressure, and salivary melatonin levels. Altered melatonin secretion was defined as an absence of evening rise, considerable irregularity, or daytime values >3 pg/ml. We additionally studied eight patients treated for craniopharyngioma.

RESULTS

Distal-proximal skin temperature gradient did not differ between NFMAs and control subjects, but proximal skin temperature was decreased during daytime (P=0.006). Core body temperature and non-dipping of blood pressure did not differ, whereas melatonin secretion was often altered in NFMAs (OR 5.3, 95% CI 0.9-30.6). One or more abnormal parameters (≥2.0 SDS of control subjects) were observed during nighttime in 12 NFMA patients and during daytime in seven NFMA patients. Similar patterns were observed in craniopharyngioma patients.

CONCLUSION

Heterogeneous patterns of altered diurnal rhythmicity in skin temperature and melatonin secretion parameters were observed in the majority of patients treated for NFMAs. On a group level, both NFMA and craniopharyngioma patients showed a lower daytime proximal skin temperature than control subjects, but other group averages were not significantly different. The observations suggest altered function of central (or peripheral) clock machinery, possibly by disturbed entrainment or damage of the hypothalamic SCN by the suprasellar macroadenoma or its treatment.