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Full-Text Articles in Biology
Melatonin Ameliorates Cisplatin-Induced Neurodegeneration In Medulla Oblongata Through The Expressions Of Aqp-1,-4, Inflammation And Apoptosis Pathway Genes, Rahi̇me Özlem Öztopuz
Melatonin Ameliorates Cisplatin-Induced Neurodegeneration In Medulla Oblongata Through The Expressions Of Aqp-1,-4, Inflammation And Apoptosis Pathway Genes, Rahi̇me Özlem Öztopuz
Turkish Journal of Biology
In this study, the neuroprotective effects of melatonin (MEL) with changes in apoptosis, inflammation, and histopathological morphology were evaluated in the medulla oblongata of cisplatin (CIS) administered rats. Although the side effects of CIS are known in many tissues, its reaction on the medulla oblongata and the molecular association underlying this effect is unclear. Male wistar albino rats were separated into four groups (control, CIS, CIS+MEL, and MEL) (n = 24). CIS and CIS+MEL groups were given 4 mg/kg CIS at 4-day intervals (days 1, 5, 9, and 13) by the first day of the study. The MEL and CIS+MEL …
The Inhibitory Effect Of Melatonin On Osteoclastogenesis Of Raw 264.7 Cells In Low Concentrations Of Rankl And Mcsf, Hala Jarrar, Damla Çeti̇n Altindal, Menemşe Gümüşdereli̇oğlu
The Inhibitory Effect Of Melatonin On Osteoclastogenesis Of Raw 264.7 Cells In Low Concentrations Of Rankl And Mcsf, Hala Jarrar, Damla Çeti̇n Altindal, Menemşe Gümüşdereli̇oğlu
Turkish Journal of Biology
RAW 264.7 cells are one of the most recommended cell lines for investigating the activity and differentiation of osteoclasts. These cells differentiate into osteoclasts in the presence of two critical components: receptor activator of nuclear factor kappa B ligand (RANKL) and macrophage colony stimulating factor (MCSF). Melatonin (MEL) hormone has recently become one of the small molecules used in the field of bone regeneration and bone disease treatment, as it has the ability to inhibit the differentiation of osteoclasts directly by suppression of the NF-κB signaling pathway. The main aim of the current study is to determine sufficient RANKL/MCSF concentrations …
Melatonin Diminishes Oxidative Damage In Sperm Cells,Improving Assisted Reproductive Techniques, Fabián Monllor, Javier Espino, Ana María Marchena, Águeda Ortiz, Graciela Lozano, Juan Francisco García, Jose A. Pariente, Ana B. Rodriguez, Ignacio Bejarano
Melatonin Diminishes Oxidative Damage In Sperm Cells,Improving Assisted Reproductive Techniques, Fabián Monllor, Javier Espino, Ana María Marchena, Águeda Ortiz, Graciela Lozano, Juan Francisco García, Jose A. Pariente, Ana B. Rodriguez, Ignacio Bejarano
Turkish Journal of Biology
Sperm preparation procedures are a potential generator of oxidative stress-induced DNA damage, which leads to a dramatic drop in fertility. An increasing number of studies suggest that melatonin reduces the oxidative stress induced by manipulation. However, very little is known about the preservative role of melatonin in sperm preparation medium during assisted reproduction procedures. For this aim to be achieved, semen was divided into two fractions and preincubated with and without 1 mM melatonin. Afterwards, both fractions were divided into two subfractions to perform swim-up in the presence and absence of 1 mM melatonin. Labeling with anti-CD46 and antiactive caspase-3 …
Involvement Of Amp-Activated Protein Kinase In The Protective Effectof Melatonin Against Renal Ischemia Reperfusion Injury, Kaouther Hadj Ayed Tka, Asma Mahfoudh Boussaid, Kaouther Kessabi, Rym Kammoun, Imed Messaoudi, Sonia Ghoul Mazgar, Joan Rosello Catafau, Hassen Ben Abdennebi
Involvement Of Amp-Activated Protein Kinase In The Protective Effectof Melatonin Against Renal Ischemia Reperfusion Injury, Kaouther Hadj Ayed Tka, Asma Mahfoudh Boussaid, Kaouther Kessabi, Rym Kammoun, Imed Messaoudi, Sonia Ghoul Mazgar, Joan Rosello Catafau, Hassen Ben Abdennebi
Turkish Journal of Biology
We investigated the implication of AMP-activated protein kinase (AMPK) in melatonin-induced protection in a renal ischemia/reperfusion (I/R) model. Animals were divided into four groups: rats of the sham group were not subjected to renal I/R. Rats in the I/R group received the vehicle 30 min before renal ischemia for 1 h followed by reperfusion for 6 h. Rats in the Mel+I/R group received melatonin (10 mg/kg) 30 min before the onset of I/R. Rats in the Mel+I/R+araA group received araA (AMPK inhibitor, 100 μg/kg per min for 10 min) just before melatonin administration. The results showed that melatonin treatment induced …
Role Of Melatonin On Differentiation Of Mesenchymal Stem Cells Derived From Third Molar Germ Tissue, Nurullah Aydoğdu, Paki̇ze Nesli̇han Taşli, Hati̇ce Burcu Şi̇şli̇, Mehmet Emi̇r Yalvaç, Fi̇kretti̇n Şahi̇n
Role Of Melatonin On Differentiation Of Mesenchymal Stem Cells Derived From Third Molar Germ Tissue, Nurullah Aydoğdu, Paki̇ze Nesli̇han Taşli, Hati̇ce Burcu Şi̇şli̇, Mehmet Emi̇r Yalvaç, Fi̇kretti̇n Şahi̇n
Turkish Journal of Biology
Stem cell-based applications have become a popular and promising approach for therapy for a number of disorders including neurodegenerative diseases, degenerative muscle diseases, and osteoporosis, as well as trauma, inflammations, burns, and injuries. Human tooth germ stem cells are an adult stem cell source; they have mesenchymal stem cell properties and show high proliferative and differentiation capacity. Melatonin has been demonstrated to regulate differentiation of human and mouse mesenchymal stem cells into various cell lineages in addition to its other functions in the body. In the current study, the effects of melatonin on osteogenic, neurogenic, adipogenic, chondrogenic, myogenic, and odontogenic …
Melatonin, Mitochondria, And Ca2+ Homeostasis In The Exocrine Pancreas: An Overview, Antonio Gonzalez, Patricia Santofimia-Castaño, Gines Maria Salido
Melatonin, Mitochondria, And Ca2+ Homeostasis In The Exocrine Pancreas: An Overview, Antonio Gonzalez, Patricia Santofimia-Castaño, Gines Maria Salido
Turkish Journal of Biology
Melatonin, a derivative of the amino acid tryptophan, was initially thought to be mainly produced and secreted by the pineal gland; with time, it was also found in other tissues and organs, and even in plants. Since its discovery, the study of the role of the indole in cellular homeostasis has generated impressive data, which have led researchers to a common idea regarding the positive actions of melatonin in health. The uncontrolled production of free radicals in cellular systems leads to the situation termed oxidative stress, which has been signaled as the basis of disease and aging. In the exocrine …
Expression Profiles Of Genes Related To Melatonin And Oxidative Stress In Human Renal Proximal Tubule Cells Treated With Antibiotic Amphotericin B And Its Modified Forms, Joanna Gola, Aleksandra Skubis, Bartosz Sikora, Celina Kruszniewska-Rajs, Jolanta Adamska, Urszula Mazurek, Barbara Strzalka-Mrozik, Grzegorz Czernel, Mariusz Gagos
Expression Profiles Of Genes Related To Melatonin And Oxidative Stress In Human Renal Proximal Tubule Cells Treated With Antibiotic Amphotericin B And Its Modified Forms, Joanna Gola, Aleksandra Skubis, Bartosz Sikora, Celina Kruszniewska-Rajs, Jolanta Adamska, Urszula Mazurek, Barbara Strzalka-Mrozik, Grzegorz Czernel, Mariusz Gagos
Turkish Journal of Biology
Melatonin protects cells from oxidative stress caused by antibiotics. Through the generation of reactive oxygen species (ROS), amphotericin B (AmB) causes oxidative injuries of the kidneys and liver. Generation of oxidized forms of AmB (AmB-ox) in a patient's circulation may also generate ROS, causing side effects. Studies aimed at elimination of toxic properties of AmB are focused on forming complexes of AmB with copper(II) ions (AmB-Cu2+). However, the influence of such modified forms on renal cells and their transcriptome has not been studied so far. Therefore, the aim of this study was to answer the question of whether AmB-Cu2+ complexes …
Melatonin Induces Antiproliferative Activity Through Modulation Of Apoptoticpathway In H-Ras Oncogene Transformed 5rp7 Cells, Ayşe Kaplan, Gülşen Akalin Çi̇ftçi̇, Hati̇ce Mehtap Kutlu
Melatonin Induces Antiproliferative Activity Through Modulation Of Apoptoticpathway In H-Ras Oncogene Transformed 5rp7 Cells, Ayşe Kaplan, Gülşen Akalin Çi̇ftçi̇, Hati̇ce Mehtap Kutlu
Turkish Journal of Biology
In the present study, cytotoxic and apoptotic effects of melatonin were investigated on H-ras oncogene transformed rat embryo fibroblast 5RP7 cells. Melatonin inhibited cell growth and induced apoptosis in 5RP7 cells. We showed inhibition of cell proliferation that was time- and dose-dependent in 5RP7 cells for 24 and 48 h. Melatonin was not toxic in NIH/3T3 primary mouse embryonic fibroblast cells at low doses for 24 and 48 h. The IC50 (380 μM) value of melatonin for 48 h was chosen for advanced assays. The percentages of early/late apoptotic cells to which melatonin (IC50: 380 μM) was administered were increased …
Melatonin Attenuates Apoptosis And Mitochondrial Depolarization Levels In Hypoxic Conditions Of Sh-Sy5y Neuronal Cells Induced By Cobalt Chloride (Cocl2), Abdülhadi̇ Ci̇hangi̇r Uğuz, Ahmi̇ Öz, Büşra Yilmaz, Seda Altunbaş, Ömer Çeli̇k
Melatonin Attenuates Apoptosis And Mitochondrial Depolarization Levels In Hypoxic Conditions Of Sh-Sy5y Neuronal Cells Induced By Cobalt Chloride (Cocl2), Abdülhadi̇ Ci̇hangi̇r Uğuz, Ahmi̇ Öz, Büşra Yilmaz, Seda Altunbaş, Ömer Çeli̇k
Turkish Journal of Biology
Melatonin (MEL) and its metabolites serve as endogenous reactive oxygen species (ROS) scavengers and have a wide spectrum of antioxidant activity. Cobalt chloride is one of the commonly used hypoxia-mimetic agents, due to blocking the degradation of and triggering the accumulation of hypoxia-inducible factor-1 alpha (HIF-1α ) protein, which is very well known as a critical regulator of the cellular response against hypoxia. In the current study we aimed to determine the possible protective effects of melatonin on a cobalt chloride-induced hypoxia model of SH-SY5Y neuronal cells. Group I was the control group and SH-SY5Y cells were incubated in normal …
Dna Protective And Antioxidative Effects Of Melatonin In Streptozotocin-Induced Diabetic Rats, Seli̇m Sekki̇n, Eda Duygu İpek, Murat Boyacioğlu, Cavi̇t Kum, Ümi̇t Karademi̇r, Hande Sultan Yalinkilinç, Mehmet Onur Ak, Hulki̇ Başaloğlu
Dna Protective And Antioxidative Effects Of Melatonin In Streptozotocin-Induced Diabetic Rats, Seli̇m Sekki̇n, Eda Duygu İpek, Murat Boyacioğlu, Cavi̇t Kum, Ümi̇t Karademi̇r, Hande Sultan Yalinkilinç, Mehmet Onur Ak, Hulki̇ Başaloğlu
Turkish Journal of Biology
Diabetes mellitus is a chronic disease characterized by elevated blood sugar levels. In diabetic patients, oxidative stress induced by the presence of excessive free radicals is closely associated with chronic in?ammation, leading to potential tissue damage. Melatonin (MEL) is a compound synthesized by the pineal gland and a scavenger of free radicals. The aim of this study was to research the effects of MEL on oxidative stress and its DNA protective effects in streptozotocin-induced diabetic rats. In total, 32 rats were equally divided into four experimental groups: control, melatonin, diabetic, and diabetic + melatonin. A single dose of streptozotocin (60 …
Effects Of Photoperiod Variations And Alpha-Lipoic Acid Treatment On Melatonin,Cortisol, And Oxidative Stress Levels In The Blood Of Rats, Cahi̇de Çevi̇k, Recep Aslan
Effects Of Photoperiod Variations And Alpha-Lipoic Acid Treatment On Melatonin,Cortisol, And Oxidative Stress Levels In The Blood Of Rats, Cahi̇de Çevi̇k, Recep Aslan
Turkish Journal of Biology
This study aimed to investigate the effects of frequently changing photoperiods and alpha-lipoic acid treatment on melatonin, cortisol, oxidative markers, and some blood parameters. Eighty-four rats were randomly and equally divided into 7 groups: a control group, 3 prolonged light groups, and 3 prolonged dark groups. The study was completed in 2 stages, with 1- and 4-week periods, respectively. Blood samples were obtained at the end of the first and fourth weeks, and at the end of the dark period for the first and second stages. Serum aspartate aminotransferase and creatinine levels were significantly elevated in the prolonged dark olive …
Melatonin Increased Vitamin C And Antioxidant Enzyme Values In The Plasma,Heart, Liver, And Kidney Of Adriamycin-Treated Rats, Ali̇ Zi̇ya Karakilçik, Muharrem Bi̇ti̇ren, Mustafa Zeri̇n, Haki̇m Çeli̇k, Nurten Aksoy
Melatonin Increased Vitamin C And Antioxidant Enzyme Values In The Plasma,Heart, Liver, And Kidney Of Adriamycin-Treated Rats, Ali̇ Zi̇ya Karakilçik, Muharrem Bi̇ti̇ren, Mustafa Zeri̇n, Haki̇m Çeli̇k, Nurten Aksoy
Turkish Journal of Biology
Adriamycin, an anticarcinogenic agent, causes excessive production of reactive oxygen species (ROS). These radicals may affect antioxidant defense systems. The present study was designed to investigate the effects of melatonin on antioxidant enzyme activities and vitamin C in Adriamycin-treated rats. In the current study, rats were divided into three groups: control, Adriamycin, and melatonin+Adriamycin groups. The control group was intraperitoneally injected physiological saline (0.9%) as a placebo. The Adriamycin and melatonin+Adriamycin groups were administered Adriamycin (25 mg/kg body weight). The melatonin+Adriamycin group was pretreated with melatonin (0.5 mg/kg body weight). Vitamin C concentration and catalase (CAT), superoxide dismutase (SOD), glutathione …
Role Of Melatonin On Calcium Signaling And Mitochondrial Oxidativestress In Epilepsy: Focus On Trp Channels, Mustafa Naziroğlu
Role Of Melatonin On Calcium Signaling And Mitochondrial Oxidativestress In Epilepsy: Focus On Trp Channels, Mustafa Naziroğlu
Turkish Journal of Biology
Calcium ion (Ca2+) accumulation and excessive oxidative stress in the hippocampus and brain cortex have long been known as major contributors to the etiology of epilepsy. I have reviewed the role of Ca2+ signaling through cation channels and mitochondria-mediated oxidative stress on epilepsy in human and animals. A review of the relevant papers and results from recent studies were obtained from PubMed and the Science Citation Index. Current literature findings indicate that melatonin and agomelatine reduce activation of hippocampal transient receptor potential (TRP), glutamate receptors, and voltage-gated calcium channels that are critical for the development of abnormal Ca2+ homeostasis and …
Melatonin As A Stabilizer Of Mitochondrial Function: Role In Diseases And Aging, Cristina Carrasco, Ana B. Rodriguez, Jose A. Pariente
Melatonin As A Stabilizer Of Mitochondrial Function: Role In Diseases And Aging, Cristina Carrasco, Ana B. Rodriguez, Jose A. Pariente
Turkish Journal of Biology
It is now almost 60 years since the discovery of melatonin and new physiological functions of the indole continuously appear in the most recent studies worldwide. Experimental evidence emphasizes its importance as a stabilizer of the mitochondrial bioenergetics, which could be related to the prevention of development of aging and several diseases. In the next years, conscientious investigation about this topic should be undertaken by scientists of different research areas to achieve a better understanding of the molecular mechanisms implied. This will ultimately allow the development and clinical application of efficacious treatments.
Prooxidant Effects Of Melatonin: A Brief Review, Malwina S. Munik, Cem Ekmekçi̇oğlu
Prooxidant Effects Of Melatonin: A Brief Review, Malwina S. Munik, Cem Ekmekçi̇oğlu
Turkish Journal of Biology
Melatonin acts classically through the widely expressed G protein-coupled membrane receptors MT1 and MT2, respectively. The functional role of the MT receptors is not fully clear with multiple effects, such as effects on the circadian, reproductive, immune, cardiovascular, and intestinal systems, being suggested. In addition to receptor-mediated effects, melatonin also acts as a potent antioxidant and it is quite evident that melatonin and its metabolites efficiently reduce oxidative damage to proteins, lipids, and DNA and also exert protective effects on mitochondria. The potent antioxidant activity of melatonin stems from various complex mechanisms, including direct scavenging of radicals, stimulation of antioxidant …
The Effects Of Agomelatine And Melatonin On Ecog Activity Of Absenceepilepsy Model In Wag/Rij Rats, Hati̇ce Aygün, Duygu Aydin, Sema İnanir, Fati̇h Eki̇ci̇, Mustafa Ayyildiz, Erdal Ağar
The Effects Of Agomelatine And Melatonin On Ecog Activity Of Absenceepilepsy Model In Wag/Rij Rats, Hati̇ce Aygün, Duygu Aydin, Sema İnanir, Fati̇h Eki̇ci̇, Mustafa Ayyildiz, Erdal Ağar
Turkish Journal of Biology
The aim of this study was to evaluate the effect of the melatonergic M1 and M2 receptor agonist and serotonergic 5-HT2C receptor antagonist agomelatine on the spike wave discharges (SWDs) seen in electrocorticographic (ECoG) recordings of WAG/Rij rats with absence epilepsy. Twenty-one WAG/Rij male rats were used in this study. Tripolar electrodes were placed on skulls and control ECoG activities were recorded. Experimental groups received normal saline (Group I: 1 mL, intraperitoneally (i.p)), agomelatine (Group II: 40 mg/kg, i.p), and melatonin (Group III: 40 mg/kg, i.p) injections for 7 days. Following this period, 2-h ECoG recordings were repeated. The number …
Melatonin Is A Potent Modulator Of Antioxidative Defense And Cellular Proliferation Against Aluminum Toxicity In Rats, Ni̇hal Ömür Bulan, Guner Sarikaya-Unal, Sevim Tunali, Pelin Arda Pi̇ri̇nççi̇, Refiye Yanardag
Melatonin Is A Potent Modulator Of Antioxidative Defense And Cellular Proliferation Against Aluminum Toxicity In Rats, Ni̇hal Ömür Bulan, Guner Sarikaya-Unal, Sevim Tunali, Pelin Arda Pi̇ri̇nççi̇, Refiye Yanardag
Turkish Journal of Biology
Aluminum is the most abundant metal on earth, known for its toxicity to humans and laboratory animals. Melatonin, produced by the pineal gland, has been shown to be an effective antioxidant. In this study, we investigated the possible protective role of melatonin in modulating toxicity and oxidative stress induced by chronic exposure to aluminum in the small intestine of rats. Wistar albino rats were divided into five groups. Group I served as the control and received only physiological saline, Group II served as the control for the melatonin group and received ethanol and physiological saline, Group III received melatonin, Group …
Serum Leptin Profiles, Food Intake, And Body Weight In Melatonin-Implanted Syrian Hamsters (Mesocricetus Auratus) Exposed To Long And Short Photoperiods, Bülent Gündüz
Turkish Journal of Biology
We have shown that circadian changes in leptin concentrations are inversely linked to circulating melatonin levels in the Syrian hamster. The present study aimed to assess the effects of subcutaneous melatonin implants under different photoperiodic conditions: did the implants affect serum leptin levels, body weight, food consumption, and/or testicular weight? Male hamsters were exposed to long and short photoperiods for 10 weeks and received subcutaneous melatonin implants (1 mg in 24 mg beeswax) every 2 weeks. Blood samples were collected every week at midday (1200 hours) or midnight (0000 hours) to assess leptin and melatonin concentrations. Testes were measured to …
Melatonin Is Effective In Reducing Stress-Induced Organ Damage In Wistar Albino Rats, Mukaddes Eşrefoğlu, Ayşi̇n Akinci Bak, Hülya Elbe, Eli̇f Taşlidere, Asli Çeti̇n, Burhan Ateş
Melatonin Is Effective In Reducing Stress-Induced Organ Damage In Wistar Albino Rats, Mukaddes Eşrefoğlu, Ayşi̇n Akinci Bak, Hülya Elbe, Eli̇f Taşlidere, Asli Çeti̇n, Burhan Ateş
Turkish Journal of Biology
In the present study, we tried to investigate the effects of melatonin, a novel antioxidant and a potent free radical scavenger, in stress-induced cerebral, cerebellar, cardiac, and hepatic oxidative damage using microscopic and biochemical analysis. A total of 32 male Wistar albino rats were divided into control, stress, stress + saline, and stress + melatonin groups. The rats from the stress groups were exposed to high stress conditions of starvation, immobilization, and cold exposure. The rats from the stress + melatonin group received melatonin daily at 20 mg/kg body weight intraperitoneally for 7 days. At the end of the experiment, …
Maternal Transfer Of Photoperiodic Information Regulates The Postnatal Reproductive System Development Of The Mongolian Gerbil (Meriones Unguiculatus), Alper Karakaş, Bülent Gündüz
Maternal Transfer Of Photoperiodic Information Regulates The Postnatal Reproductive System Development Of The Mongolian Gerbil (Meriones Unguiculatus), Alper Karakaş, Bülent Gündüz
Turkish Journal of Biology
We investigated whether photoperiodic information is transferred from mother to young and whether the pineal gland and its hormone, melatonin, are involved in this transfer in Mongolian gerbils. Adult female gerbils were paired with males and housed in photoperiods of 12L:12D or 8L:16D. Three groups of pregnant gerbils in each photoperiod were prepared: one group was the sham-operated control, one group consisted of pinealectomized gerbils, and one group consisted of pinealectomized gerbils that were treated with melatonin. Pinealectomy was performed before pairing the animals and melatonin injections were applied to the pinealectomized group from day 8 of gestation until parturition. …
Melatonin Implants Have No Effect On The Testis Volume And Body Weight In Mongolian Gerbils, Alper Karakaş, Bülent Gündüz
Melatonin Implants Have No Effect On The Testis Volume And Body Weight In Mongolian Gerbils, Alper Karakaş, Bülent Gündüz
Turkish Journal of Biology
Photoperiod is an important environmental cue in the regulation of reproductive activity in Mongolian gerbils. Photoperiodic information is ultimately transduced into a hormonal signal by the pineal gland. We examined the effect of constant-release melatonin capsules on the testicular size and body weights of male Mongolian gerbils exposed to a long (14L: 10D) photoperiod. Three groups were formed: control (n = 10), intact + melatonin implant (n = 10) and pinealectomy + melatonin implant (n = 10). The testes and body weights of the gerbils were recorded every week for 8 weeks. Body weights (76 ± 2.0 g intact + …
Reproductive Response Of Adult Siberian Hamsters To One-Hour Melatonin Infusions, Bülent Gündüz, Milton H. Stetson
Reproductive Response Of Adult Siberian Hamsters To One-Hour Melatonin Infusions, Bülent Gündüz, Milton H. Stetson
Turkish Journal of Biology
The pineal hormone melatonin is known to play an important role in mediating photoperiodic messages to the reproductive system in seasonal breeding animals. In this study, we investigated whether a 1 h subcutaneous infusion of 50 ng of melatonin at 2000-2100 hours, effective in causing inhibition of testicular development in the juvenile Siberian hamsters (Phodopus sungorus), would cause testicular regression in adults of this species housed on a long photoperiod (LD16:8). Pinealectomized adult hamsters received programmed subcutaneous infusions of 50 or 500 ng of melatonin or vehicle (0.12 ml) at 2000-2100 hours each day for 8 weeks. We found that …
Effects Of Photoperiod And Melatonin Infusions On Body Weight In Pinealectomized Juvenile Siberian Hamsters (Phodopus Sungorus), Bülent Gündüz, Alper Karakaş
Effects Of Photoperiod And Melatonin Infusions On Body Weight In Pinealectomized Juvenile Siberian Hamsters (Phodopus Sungorus), Bülent Gündüz, Alper Karakaş
Turkish Journal of Biology
We examined the effects of daily melatonin (Mel) infusions in pinealectomized prepubertal male Siberian hamsters in three different conditions. In one study we investigated the body weight maturation response to one hour daily infusions of 10 ng, 25 ng, or 50 ng of Mel in pinealectomized hamsters. Animals received, at day 15 of life, programmed subcutaneous infusions of Mel or vehicle at one of five time points (1900-2000, 2000-2100, 2100-2200, 2400-0100, and 0300-0400 hours) for 30 days. In long-day-born (16L) animals, Mel infusion right after lights off (2000-2100 hours) significantly inhibited body growth; this dose was ineffective at other times. …