Influence of Photoperiod on Pineal Melatonin Synthesis, Fur Color, Body Weight, and Reproductive Function in the Female Djungarian Hamster, Phodopus sungorus

1993 ◽  
Vol 57 (2) ◽  
pp. 359-364 ◽  
Author(s):  
Alexander Lerchl ◽  
Stefan Schlatt
Keyword(s):  
Body Weight ◽  
Reproductive Function ◽  
Phodopus Sungorus ◽  
Djungarian Hamster ◽  
Color Body ◽  
Pineal Melatonin ◽  
Melatonin Synthesis ◽  
Fur Color

Monosodium glutamate administration early in life alters pineal melatonin nocturnal profile in adulthood

2021 ◽  
Vol 4 (1) ◽  
pp. 99-114
Author(s):  
Janaína B Garcia ◽  
Fernanda G Do Amaral ◽  
Daniela C Buonfiglio ◽  
Rafaela FA Vendrame ◽  
Patrícia L Alves ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Pineal Gland ◽  
Serum Insulin ◽  
Monosodium Glutamate ◽  
Female Rats ◽  
Pineal Melatonin ◽  
Melatonin Synthesis ◽  
Male And Female Rats ◽  
Melatonin Production

The pineal gland synthesizes melatonin exclusively at night, which gives melatonin the characteristic of a temporal synchronizer of the physiological systems. Melatonin is a regulator of insulin activities centrally and also peripherally and its synthesis is reduced in diabetes.  Since monosodium glutamate (MSG) is often used to induce the type 2 diabetic and metabolic syndrome in animal models, the purpose of this work is to evaluate the potential effects of MSG given to neonates on the pineal melatonin synthesis in different aged male and female rats. Wistar rats were subcutaneously injected with MSG (4mg/g/day) or saline solution (0.9%) from the second to eighth post-natal day. The circadian profiles both melatonin levels and AANAT activity were monitored at different ages. Body weight, naso-anal length, adipose tissues weight, GTT, ITT and serum insulin levels were also evaluated. Typical obesity with the neonatal MSG treatment was observed, indicated by a great increase in adipose depots without a concurrent increase in body weight. MSG treatment did not cause hyperglycemia or glucose intolerance, but induced insulin resistance. An increase of melatonin synthesis at ZT 15 with phase advance was observed in in some animals. The AANAT activity was positively parallel to the melatonin circadian profile. It seems that MSG causes hypothalamic obesity which may increase AANAT activity and melatonin production in pineal gland. These effects were not temporally correlated with insulin resistance and hyperinsulinemia indicating the hypothalamic lesions, particularly in arcuate nucleus induced by MSG in early age, as the principal cause of the increase in melatonin production.

Urinary 6-sulphatoxymelatonin excretion reflects pineal melatonin secretion in the Djungarian hamster (Phodopus sungorus)

1995 ◽  
Vol 18 (2) ◽  
pp. 69-76 ◽  
Author(s):  
Ariane Stieglitz ◽  
Frank Spiegelhalter ◽  
Gabriela Klante ◽  
Gerhard Heldmaier
Keyword(s):  
Phodopus Sungorus ◽  
Djungarian Hamster ◽  
Melatonin Secretion ◽  
Pineal Melatonin
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