ISSN:
1435-1463
Keywords:
Melatonin
;
pinealectomy
;
sham-pinealectomy
;
shielded pineal region
;
testes
;
male accessory glands
;
pituitary
;
adrenal glands
;
male Golden Hamsters
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Testes, accessory glands, pituitaries and adrenal glands from 101 male Golden Hamsters (55–65 days old) were weighed after 4 weeks of daily injections of vehicle or 25μg or 2500μg of melatonin, and 32–33 days after surgery. The surgical groups within each injection group were: (1) nonoperated (NO), (2) sham-pinealectomized (S), (3) sham-pinealectomized with black plastic shielding of the pineal region (S+Pl), (4) pinealectomized (PX), and (5) pinealectomized with black plastic shielding of the pineal region (PX+Pl). All injections were made between L11 and L11.75 in a fixed LD 14∶10 daily photoperiod. Absolute and relative organ weights were significantly depressed by 25 but not 2500μg melatonin. This effect of low dose melatonin was blocked by pinealectomy (PX, PX+Pl) in all four organ groups, but was blocked as well by the sham-operation (S, S+Pl) only in the case of the adrenal glands. Effects and organ weights in S animals were not modified in the S+Pl animals. But in vehicle-injected groups the S+Pl animals had significantly lower accessory organ weights in comparison with those of NO and S groups. These results aid in the further definition of the mechanisms of melatonin's physiological actions as a chemical mediator within neuroendocrine timing controls, and show that the mechanisms for melatonin's actions can differ in relation to eventual endpoint target tissue or organ studied.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01243520
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