5-Hydroxytryptophan-stimulated prolactin levels in cafeteria diet fed rats: an in vivo evaluation of the central serotonergic tonus.
Hyperphagia in rats fed a cafeteria diet might be related to the palatability of the diet or to diet-induced changes in central neurotransmitters regulating the feeding behavior. In this study the central serotonergic tonus in adult male Wistar rats was evaluated in vivo after 6 weeks of feeding a cafeteria diet by the prolactin response to the administration of 5-hydroxytryptophan (5HTP), the immediate serotonin precursor. Blood was taken just before, 30, 60 and 90 min after the ip injection of 50 mg/kg 5HTP for the determination of prolactin concentrations were comparable between cafeteria fed rats and control rats, fed normal laboratory chow (12.7 +/- 5.4 vs 7.7 +/- 4.5 ng/ml). The 5HTP-stimulated prolactin secretion in the cafeteria diet fed rats, determined by the peak value (95.8 +/- 17.2 vs 119.1 +/- 27.0 ng/ml) as well as by the integrated area under the curve (5478 +/- 774 vs 5916 +/- 2275 ng/ml. 90 min) was not significantly lower than in the control rats. In conclusion, our results did not show a significantly decreased 5HTP-induced prolactin release in cafeteria-fed rats, suggesting that a low hypothalamic serotonergic tonus is probably not involved in the overeating of this dietary-induced obesity model.
De Schepper
J
J
Dept. of Pediatrics, Faculty of Medicine, Vrije Universiteit Brussel, Belgium.
Zhou
X
X
Velkeniers
B
B
Hooghe-Peters
E
E
Vanhaelst
L
L
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage; D005069:Evaluation Studies as Topic; D008297:Male; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000502:physiology; D018490:Serotonin Agents / Q000494:pharmacology
D004041:Dietary Fats; D018490:Serotonin Agents; D012701:Serotonin; D011388:Prolactin; D006916:5-Hydroxytryptophan