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Pineal Gland Abstracts: 1996

Note: the following is a limited selection of abstracts available at PubMed, Science Direct, and Toxnet.

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http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8912232&dopt=Abstract

J Pineal Res 1996 Sep;21(2):73-9

5-Methoxytryptophol and melatonin in children: differences due to age and sex.

Molina-Carballo A, Munoz-Hoyos A, Martin-Garcia JA, Uberos-Fernandez J, Rodriguez-Cabezas T, Acuna-Castroviejo D.

Departamento de Pediatria, Hospital Clinico Universitario de Granada, Spain.

It seems clear that the pineal hormone, melatonin (N-acetyl-5-methoxytryptamine), is involved in the reproductive behavior of several animal species including humans. Moreover, several data also support a role for 5-methoxytryptophol (ML), another pineal hormone, in the control of sexual processes. To test the role of ML in human reproductive axis, 128 healthy children, 68 boys and 60 girls, were studied. Each of these groups was divided in three age subgroups of 6, 11, and 14 years. A single blood sample (0900 hours) was obtained from each subject to determine melatonin, ML, FSH, LH, estradiol (girls), and testoterone (boys) by RIA. Statistical analysis of the data included ANOVA-II (factor I: age, factor II: sex) and an analysis of covariance with age as covariate. A similar plasma melatonin concentration, with a significant decrease between 6 and 11 years, was found in boys and girls. Melatonin concentrations correlate well with initiation of the pubertal development in these children, although no sex differences were found. Concentrations of ML are approximately 50% of those of melatonin. In contrast to melatonin, ML levels show significant age and sex differences. Plasma ML concentration significantly increased in boys (P < 0.001) and decreased in girls (P < 0.001) after 8 years of age. These results support the hypothesis that, besides melatonin, other pineal compounds such as ML may be involved in the maturation process in humans. The pineal indole ML may also be used as a marker of the different chronobiology in the pubertal development in boys and girls.

PMID: 8912232 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8866243&dopt=Abstract

J Neuroendocrinol 1996 Aug;8(8):571-7

Brain and pituitary melatonin receptors in male rat during post-natal and pubertal development and the effect of pinealectomy and testosterone manipulation.


Zitouni M, Pevet P, Masson-Pevet M.

URA CNRS 1332, Universite Louis Pasteur, Strasbourg, France.

Using quantitative autoradiography, melatonin receptors have been studied during post-natal and pubertal development of the rat in 2 brain and 2 pituitary structures. In the pars distalis of anterior pituitary, melatonin receptors decrease gradually in density after birth and disappear in 30 day-old animals. In contrast melatonin binding is only expressed in the paraventricular nuclei of the thalamus at the age of 21-23 days and is always present in adult animals. In the suprachiasmatic nuclei and in the pars tuberalis of the pituitary, melatonin receptor density decreases after birth, remains stable for approximately 1 month and increases again at puberty to reach the birth values in the adult. This increase was absent in pinealectomized and in castrated animals but present in castrated animals receiving testosterone suggesting that it depends upon circulating testosterone and melatonin levels. These results show that melatonin receptors are differentially regulated during post-natal development in each of the 4 structures studied, and that melatonin and testosterone are 2 factors which could be involved in the regulation of melatonin receptor density in the suprachiasmatic nuclei and pars tuberalis.

PMID: 8866243 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8674076&dopt=Abstract

Childs Nerv Syst 1996 Feb;12(2):103-6

Pineal ganglioglioma with premature thelarche. Report of a case and review of the literature.


Chang YL, Lin SZ, Chiang YH, Liu MY, Lee WH.

Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, R.O.C.

We report a case of a 6-year-old girl with a ganglioglioma in the pineal region presenting with a rare clinical picture of premature thelarche. Intracranial gangliogliomas are rare, especially in the pineal region. Their character, origin, treatment, and prognosis remain controversial. The pathophysiology of precocious puberty associated with pineal ganglioglioma is discussed.

PMID: 8674076 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8989721&dopt=Abstract

J Pineal Res 1996 Nov;21(4):225-30

6-Hydroxymelatonin sulfate excretion in human puberty.


Cavallo A, Dolan LM.

Department of Pediatrics, University of Cincinnati College of Medicine, Children's Hospital Medical Center, OH 45229-3039, USA.

We investigated the relationship of urinary excretion rate of 6-hydroxymelatonin sulfate (SM), the main metabolite of melatonin, with pubertal development and determined the day to day variability of SM excretion. Healthy subjects 4-31 years old completed one or multiple timed overnight urine collections. SM excretion rate per body size was significantly higher in 99 prepubertal subjects (35.5 +/- 2.3 ng/h/kg and 0.97 +/- 0.06 microgram/hr/m2) than in 86 pubertal subjects (18.1 +/- 1.1 ng/hr/kg and 0.61 +/- 0.03 microgram/hr/m2) or in 29 adults (15.0 +/- 1.5 ng/hr/kg and 0.59 +/- 0.06 microgram/hr/m2); no significant difference was present in pubertal stages 2 to 5. Among the prepubertal children, SM excretion rate in mid childhood was significantly higher than in late childhood. The variability of SM and creatinine excretion examined in 52 children, adolescents and adults with three or four collections was defined as the mean of the 52 coefficients of variation for the multiple measures in each subject. The variability of total nocturnal SM (25.9 +/- 2.6%) was similar to that of total creatinine (21.7 +/- 2.3%) and neither was significantly correlated with the variability in start time or duration of urine collection. The results suggest that, relative to body size, melatonin secretion rate is higher in mid childhood, decreases during late childhood, and remains stable from pubertal stage 2 to adulthood. The decline in melatonin secretion rate occurs during the developmental phase of disinhibition of the gonadotropin releasing hormone pulse generator. Hence, we infer that melatonin may be a suppressive factor of puberty during childhood. The substantial individual variability observed for SM excretion calls for caution in using single urine collections in longitudinal studies or in studies of drug responses.

PMID: 8989721 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8689660&dopt=Abstract

Cas Lek Cesk 1996 Apr 17;135(8):231-5

[Melatonin--the hormone of darkness]


[Article in Czech]

Kancheva RL, Zofkova I.

Endokrinologicky ustav, Praha.

Melatonin is a hormone produced mainly by the pineal gland during the dark phase of the circadian cycle with typical circadian rhythm with maximal secretion at night and depression during the day. The indoleamine has wide regulatory and integrative functions. Perhaps there is no organ and system which can escape the influence of epiphysis, incl. reproductive, cardiovascular gastrointestinal, respiratory as well as renal system and water and mineral metabolism. Melatonin regulates not only neuroendocrine functions but also has immunoenhancing and antitumor effects. That is why there are trials/attempts these properties to be utilized in the treatment of malignancies and AIDS patients. The hormone plays a certain role in temperature regulation in mammals as well as in the onset of puberty and senescence. Attention has been paid to its role as a scavenger of toxic free radicals and it is believed that melatonin is the most effective lipophilic antioxidant. However, the exact mechanism of action of this high active hormone remains to be elucidated. Further studies are also necessary for discovering the next its properties and functions.

Publication Types:
PMID: 8689660 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8873893&dopt=Abstract

J Mol Neurosci 1996 Summer;7(2):91-8

Abnormal melatonin secretion in male patients with hypogonadism.


Luboshitzky R, Wagner O, Lavi S, Herer P, Lavie P.

Endocrine Institute, Central Emek Hospital, Afula, Israel.

Recently we have demonstrated that melatonin secretion is increased in untreated male patients with GnRH deficiency. Testosterone administration to these patients decreased melatonin secretion to normal levels. These data, however, did not exclude a gonadotropic effect on melatonin secretion. To further elucidate whether gonadal steroids and/or gonadotropins modulate melatonin secretion in humans we compared untreated young males with hypogonadotropic hypogonadism (IGD, n = 6), and hypergonadotropic hypogonadism caused by KlinEfelter's syndrome (KS, n = 11) to normal pubertal male controls (n = 7). KS patients were subdivided into two groups: KS-1, with low testosterone; and KS-2, with normal testosterone levels. Serum samples for melatonin concentrations were obtained every 15 min from 7 PM to 7 AM in a controlled light-dark environment with simultaneous sleep recordings. All KS patients had elevated gonadotropin levels and decreased melatonin levels. Mean (+/- SD) dark-time nocturnal melatonin levels in KS-1 were 92 +/- 21 pmol/L and were 146 +/- 46 pmol/L in KS-2 compared with 178 +/- 64 pmol/L in controls. Integrated nocturnal melatonin secretion values (AUC) were 64 +/- 14 pmol/min x L x 10(3) in KS-1 and 96 +/- 29 pmol/min x L x 10(3) in KS-2 compared with 116 +/- 42 pmol/min x L x 10(3) in controls. All IGD patients had low gonadotropin and testosterone levels. Their dark-time melatonin levels (286 +/- 26 pmol/L) and the AUC values (184 +/- 15 pmol/min/L x 10(3)) were increased. These data indicate that melatonin secretion is increased in male patients with GnRH deficiency and decreased in low testosterone hypergonadotropic hypogonadal patients. Taken together, our results suggest that both gonadotropins and gonadal steroids modulate melatonin secretion in humans.

PMID: 8873893 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8636302&dopt=Abstract

J Clin Endocrinol Metab 1996 Feb;81(2):770-4

Testosterone treatment alters melatonin concentrations in male patients with gonadotropin-releasing hormone deficiency.


Luboshitzky R, Lavi S, Thuma I, Lavie P.

Endocrine Institute, Central Emek Hospital, Afula, Israel.

Recently, we demonstrated that melatonin secretion is increased in untreated male patients with GnRH deficiency. As testosterone (T) can be aromatized to estradiol (E2), and both T and E2 increase during T enanthate treatment, we were interested in determining whether T treatment (when T and E2 levels were well matched with pubertal control values) has an effect on melatonin levels in these patients. We measured nocturnal serum melatonin levels during the administration of 250 mg testosterone enantale/month for 4 months in 12 male patients with idiopathic hypogonadotropic hypogonadism (IGD; n = 6) and delayed puberty (DP; n = 6). Serum samples for melatonin and LH determinations were obtained every 15 min from 1900-0700 h in a controlled light-dark environment. The results of melatonin profiles were compared with the pretreatment values in each group and with values obtained in six normal pubertal male controls. After 4 months of testosterone treatment, all patients attained normal serum testosterone (19.5 +/- 3.7 in IGD vs. 20.8 +/- 4.1 nmol/L in DP) and E2 levels (83 +/- 12 in IGD vs. 84 +/- 9 pmol/L in DP). Serum LH levels were suppressed in all patients during T treatment (0.12 +/- 0.1 in IGD vs. 0.12 +/- 0.2 IU/L in DP). Before T treatment, patient melatonin levels were greater than those in age-matched pubertal controls. Melatonin levels were equal in patients and controls when T and E2 levels were well matched. Mean (+/- SD) dark-time melatonin levels decreased from 286 +/- 23 to 157 +/- 36 pmol/L in IGD and from 217 +/- 32 to 133 +/- 47 pmol/L in DP (vs. 183 +/- 64 pmol/L in controls). The integrated melatonin values decreased to normal (from 184 +/- 16 to 102 +/- 21 in IGD and from 142 +/- 19 to 90 +/- 26 pmol/min.L x 10(3) in DP vs. 119 +/- 61 pmol/min.L x 10(3) in controls). The intraindividual variations in melatonin levels ranged from 7.2-14.5%. These data indicate that male patients with GnRH deficiency have increased nocturnal melatonin secretion. T treatment decreased melatonin secretion to normal levels. The results suggest that in GnRH-deficient male patients, sex steroids, rather than LH, modulate pineal melatonin in a reverse fashion.

PMID: 8636302 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8797178&dopt=Abstract

J Pineal Res. 1996 Apr;20(3):115-24.

Scientific research on the pineal gland and melatonin: a bibliometric study for the period 1966-1994.

Lopez-Munoz F, Boya J, Marin F, Calvo JL.

Department of Histology, Faculty of Medicine, Complutense University, Madrid, Spain.

By means of teledischarge techniques from the database MEDLINE we selected those documents that contained in their title one or several of the following descriptors: pineal*, epiphys*, or melatonin*, in addition to the descriptor pineal-body in the MESH (Medical Subject Headings) section. A total of 7,617 original documents published between 1966 and 1994 were extracted that dealt with any aspect related with the pineal gland or its main secretary product, melatonin. The main bibliometric laws were applied: Price's Law on the increase in scientific literature, Bradford's Law on the dispersion of the scientific literature, and Lotka's Law on the author's productivity. Furthermore, we have analyzed the participation index (PaI) of the main countries within the global production, the productivity index of the authors (PI), and the number of authors/paper index. Our results demonstrate an exponential increase of the scientific literature on the pineal gland ("r" value = 0.983, in contrast with a "r" value = 0.966 after the linear adjustment). The number of publications on melatonin was less than those on other aspects of pineal research until 1991, when this situation was reversed. The journal with the largest number of original papers is Journal of Pineal Research (1st Bradford's zone) with 533 articles, followed by Journal of Neural Transmission (258) and Neuroendocrinology (221), which constituted the 2nd Bradford's zone. The total number of authors is 9,140, responsible for 23,524 authorships. 3.8% of the authors present a PI > or = 1 (large producers), and 64.9% a PI = 0 (occasional authors). Lotka's Law was widely fulfilled in this material since 10.3% of the authors are responsible of 50.2% of all the papers. The average number of authors per paper has changed from 2.29 in 1966 to 3.85 in 1994. The most productive country (during the interval between 1988-1994) was USA (PaI = 30.6), followed by Japan (7.15), United Kingdom (6.45), Germany (6.37), France (6.26), Italy (6.15) and Spain (5.34). Of the total number articles published, 86.9% are in English.

PMID: 8797178 [PubMed - indexed for MEDLINE]