Long-term melatonin administration does not alter pituitary-gonadal hormone secretion in normal men

2000 ◽  
Vol 15 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Rafael Luboshitzky ◽  
Michal Levi ◽  
Zila Shen-Orr ◽  
Zeev Blumenfeld ◽  
Paula Herer ◽  
...  
Keyword(s):  
Hormone Secretion ◽  
Gonadal Hormone ◽  
Melatonin Administration ◽  
Normal Men

Influence of N-methyl-d-aspartate on the reproductive axis of male Syrian hamsters

1993 ◽  
Vol 137 (2) ◽  
pp. 247-NP ◽  
Author(s):  
H. F. Urbanski ◽  
M. M. Fahy ◽  
P. M. Collins
Keyword(s):  
Hormone Secretion ◽  
Serum Testosterone ◽  
Inhibitory Effect ◽  
Stimulatory Action ◽  
Syrian Hamsters ◽  
Reproductive Axis ◽  
Treatment Paradigm ◽  
Testicular Size ◽  
Lh Releasing Hormone

ABSTRACT The influence of excitatory amino acids (EAAs) on reproductive neuroendocrine function was investigated in adult male Syrian hamsters of the LSH/Ss Lak strain. Before the study, the animals were maintained in a sexually regressed condition, under short days (SD) and subsequently were either transferred to long days (LD) or kept under SD, for a further 4 weeks. In the former group, photostimulation produced a predictable elevation in the hypophysial contents and serum concentrations of FSH and LH. This was accompanied by an increase in testicular size, an elevation in serum testosterone levels and an increase in spermatogenic activity; the SD hamsters remained sexually quiescent throughout the study. In contrast, SD hamsters that were given daily injections of the EAA agonist, N-methyl-d,l-aspartate (NMA: 50 mg/kg body weight, s.c.), showed stimulatory responses that were generally even more pronounced than those shown by the LD group. Surprisingly, an identical NMA treatment paradigm failed to cause a similar activation of the reproductive axis in LD hamsters that were given daily afternoon injections of melatonin (25 μg, s.c), even though the inhibitory effect of this melatonin treatment is generally regarded as being comparable with that produced by exposure to SD. Although EAAs can acutely stimulate the neurocircuitry that controls LH-releasing hormone secretion, the present findings suggest that EAAs might also exert a long-term stimulatory action by acting further upstream in the photoneuroendocrine pathway. Journal of Endocrinology (1993) 137, 247–252

EFFECT OF CORTICOSTEROIDS ON URINARY 5β AND 5α C19 STEROIDS IN MAN

1964 ◽  
Vol 46 (2) ◽  
pp. 197-206 ◽  
Author(s):  
Hildegard Wilson ◽  
Steven Schenker
Keyword(s):  
Testosterone Propionate ◽  
Periodic Fever ◽  
Term Treatment ◽  
Long Term Treatment ◽  
Dexamethasone Therapy ◽  
Normal Women ◽  
Normal Men ◽  
Short Time

ABSTRACT A high proportion of urinary C19 5β to 5α steroid metabolites has been found on administration of glucocorticoids in a number of instances. During long term treatment with prednisone or dexamethasone, 100 mg testosterone propionate was administered to 3 patients. The ratios of the resulting metabolites etiocholanolone (E, 5β) to androsterone (A, 5α) were 2.7, 3.3 and 2.1, compared to 1.3 and 0.9 after withdrawal of corticoids from the first 2 patients. In 3 normal men, ratios of endogenously derived E and A while receiving corticoids, compared to control ratios were 2.3 to 1.0, 2.2 to 0.6 and 1.2 to 0.9. Ratios in normal women rose from 1.1 to 2.2 and 2.4 to 4.3 on receiving dexamethasone. Not all subjects gave the expected response. In 3 of these the dosage of corticoid was either low or given for a short time. The ratio of C19O3 metabolites of administered 11β-hydroxy-androst-4-ene-3,17-dione was also changed in favour of the 5β products during corticoid treatment. In a man with periodic fever the high E/A ratios observed were probably related to dexamethasone therapy rather than to the disease.

scholarly journals Antioxidant Strategies and Respiratory Disease of the Preterm Newborn: An Update

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Chiara Poggi ◽  
Carlo Dani
Keyword(s):  
Lung Damage ◽  
Preterm Newborn ◽  
Beneficial Effects ◽  
Melatonin Administration ◽  
Targeted Treatments ◽  
Wide Range ◽  
Nonenzymatic Antioxidants ◽  
Respiratory Outcomes ◽  
Preterm Newborns

Preterm newborns are challenged by an excessive oxidative burden, as a result of several perinatal stimuli, as intrauterine infections, resuscitation, mechanical ventilation, and postnatal complications, in the presence of immature antioxidant capacities. “Oxygen radical disease of neonatology” comprises a wide range of conditions sharing a common pathway of pathogenesis and includes bronchopulmonary dysplasia (BPD) and other main complications of prematurity. Antioxidant strategies may be beneficial in the prevention and treatment of oxidative stress- (OS-) related lung disease of the preterm newborn. Endotracheal supplementation or lung-targeted overexpression of superoxide dismutase was proved to reduce lung damage in several models; however, the supplementation in preterm newborn failed to reduce the risk of BPD, although long-term respiratory outcomes were improved. Also melatonin administration to small cohorts of preterm newborns suggested beneficial effects on lung OS. The possibility to identify single nucleotide polymorphism affecting the risk of BPD may help to identify specific populations with particularly high risk of OS-related diseases and may pose the basis for individually targeted treatments. Finally, surfactant replacement may lead to local anti-inflammatory and antioxidant effects, thanks to specific enzymatic and nonenzymatic antioxidants naturally present in animal surfactants.

Sleep deprivation reduces LH secretion in men independently of melatonin

1991 ◽  
Vol 124 (6) ◽  
pp. 646-651 ◽  
Author(s):  
RickJ. Strassman ◽  
Clifford R. Qualls ◽  
E.Jonathan Lisansky ◽  
Glenn T. Peake
Keyword(s):  
Sleep Deprivation ◽  
Hormone Secretion ◽  
Area Under The Curve ◽  
Bright Light ◽  
Pulse Frequency ◽  
Blood Levels ◽  
Luteinizing Hormone Secretion ◽  
Normal Man ◽  
Normal Men ◽  
Lh Secretion

Abstract. Melatonin affects gonadal function in nonprimate mammals. Confirmatory data in man are not available. We assessed melatonin's acute effects on luteinizing hormone secretion in 17 normal men. We studied these men in conditions of sleep in the dark, and sleep deprivation in bright light, dim light, and bright light combined with a physiologically relevant infusion of melatonin, while measuring blood levels of immunoreactive LH every 20 min for 7 h. We compared overnight LH secretion, and LH pulse frequency, amplitude, length, interval and area under the curve using a modification of the PULSAR peak identification program, among the four treatments. Areas under the curve for peaks in all three conditions of sleep deprivation were lower than in normal sleep. The presence or absence of melatonin had no additional effect. We conclude that acute suppression of melatonin does not affect LH pulse parameters in normal man, but that sleep deprivation may reduce the amount of LH secreted per pulse.

Twenty-Four Hour Pattern of Luteinizing Hormone Secretion in Normal Men with Sleep Stage Recording

1972 ◽  
Vol 35 (1) ◽  
pp. 73-81 ◽  
Author(s):  
ROBERT BOYAR ◽  
MARK PERLOW ◽  
LEON HELLMAN ◽  
SHELDON KAPEN ◽  
ELLIOT WEITZMAN
Keyword(s):  
Luteinizing Hormone ◽  
Sleep Stage ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion ◽  
Normal Men

scholarly journals Abdominal Paragangliomas: Analysis of Surgeon's Experience

2011 ◽  
Vol 3 (2) ◽  
pp. 55-58 ◽  
Author(s):  
SC FitzGerald ◽  
Gingell Littlejohn M ◽  
CN Parnaby ◽  
JM Connell ◽  
PJ O'Dwyer
Keyword(s):  
Clinical Presentation ◽  
Hormone Secretion ◽  
Endocrine Tumor ◽  
Capsular Invasion ◽  
Urinary Catecholamine ◽  
Surgical Department ◽  
Common Presentation ◽  
Genetic Abnormalities

ABSTRACT Abdominal paraganglioma is a rare endocrine tumor associated with genetic mutations, however, the ability to predict long-term risk of metastasis has not been clarified. The aim of this study was to examine the clinicopathological features and outcomes in patients undergoing surgery for an abdominal paraganglioma. A retrospective analysis was performed for all patients undergoing surgery for abdominal paragangliomas from one surgical department between 1998 and 2010. Clinical presentation, hormone secretion and clinical outcomes were examined. A total of 23 patients underwent surgery for abdominal paraganglioma with the most common presentation being hypertension. Median time to metastasis was 32 months with all patients developing disease progression having a rise in urine catecholamines. Patients with capsular invasion or predisposing genetic conditions are at a higher risk of having more aggressive disease. All patients with a diagnosis of paraganglioma should be screened for predisposing genetic abnormalities and postoperative follow-up must include routine urinary catecholamine assessment.

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