The relationship between the pineal gland and aging has been assumed already nearly a century ago. Recently, melatonin was considered by some authors as a "wonder drug." The present paper tries to summarize the relationship between melatonin and aging in three points. 1. Decline of melatonin production during aging. 2. The role of the pineal gland in the regulation of the ovarian cycle in aged ...

Melatonin is a substance chiefly produced by the pineal gland and has a key role in the sleep-wake cycle. It also has an important antioxidant role. Exogenous melatonin has a short half-life and is available in a range of preparations. Newer analogues targeted for the recently discovered melatonin MT1 and MT2 receptors have also been developed. Exogenous melatonin is used as a resynchronisation...

We assessed the influence of perinatal melatonin on reproductive development and adult responsiveness to melatonin. Testicular growth in an intermediate day length (14 : 10 h light/dark cycle) was substantially reduced in Siberian hamsters gestated by pinealectomised compared to pineal-intact females; gonadal development was normalised in offspring of pinealectomised dams that were pinealectomi...

In Siberian hamsters (Phodopus sungorus), short days suppress reproductive function and lymphocyte proliferation. To determine whether melatonin influences cell-mediated immunity through a direct action on lymphocyte proliferation, in vitro responsiveness to mitogens and melatonin was assessed in systemic and splenic lymphocytes from adult female Siberian hamsters housed in either long or short...

Retinal synthesis of melatonin, a potent modulator of rhythmic retinal processes, is elevated at night as a result of regulation by a circadian clock. Despite high nocturnal synthetic capacity, both melatonin content and release are low in the retina of the frog Xenopus laevis. We report here that cultured eyecups from Xenopus have the capacity for rapid metabolic breakdown of melatonin. Pharma...

Melatonin (N-acetyl-5-methoxytryptamine) is secreted in the pineal gland and extra pineal tissues. Melatonin possesses a wide variety of biological effects such as chronobiological, sedative and anxiolytic. Melatonin may act as an antioxidant and a potent scavenger of both oxygen and nitrogen reactive molecules. The free radical scavenging activity of melatonin is receptor independent process w...

Melatonin madness is everywhere! The media attention that melatonin has received recently is truly remarkable and has elevated the hormone to cult status. Is all this excitement really justified, or is it just hype? What does melatonin actually do? Does it signal through specific receptors like other hormones? What is its true therapeutic potential? This minireview addresses these questions and...

Since mammalian skin expresses the enzymatic apparatus for melatonin synthesis, it may be an extrapineal site of melatonin synthesis. However, evidence is still lacking that this is really the case in situ. Here, we demonstrate melatonin-like immunoreactivity (IR) in the outer root sheath (ORS) of mouse and human hair follicles (HFs), which corresponds to melatonin, as shown by radioimmunoassay...

Background: The relationship between the high activity of aldose reductase (AR) and diabetic cataract formation has been previously investigated. The purpose of the present study was to determine the preventing effect of melatonin on streptozotocin (STZ)-induced diabetic cataract in rats.Methods: 34 adult healthy male Sprague-Dawely rats were divided into four groups. Diabetic control and diabe...

Melatonin is a new plant hormone that plays an important role in stress tolerance. For investigation the effect of exogenous application of melatonin on salt tolerance in rosemary (Rosmarinus officinalis L.), a factorial experiment was conducted in a completely randomized design with three replications. The first factor was melatonin (50, 100 µM) and the second factor was salinity stress (6, 9,...