Role of the glucopyranose ring in the elicitation of feeding
Sakata, T.; Fujimoto, K.; Kurata, K.; Etou, H.; Fukagawa, K.; Okabe, Y.; Ookuma, K.
International Journal of Obesity 11 Suppl. 3: 27-33
1987
ISSN/ISBN: 0307-0565 PMID: 3440689 Document Number: 289949
To relate the structural characteristics of the glucose pyranose ring to feeding elicitation, biochemically and structurally similar glucose analogues were investigated to determine if they could elicit short- or long-term effects on food intake in rats. Testing solutions were infused once into unrestrained and unanesthetised rats through a chronically indwelling cannula in the third ventricle. D-Glucose markedly decreased meal size in doses from 6 to 24 mumol, but it's epimers, D-mannose, D-allose and D-galactose, did not affect food intake. Among the glucose analogues modified at C-2, rats treated with 12 mumol D-glucosamine ate a much larger size of meal than those with 12 mumol halogenglucoses or 24 mumol 2-deoxy-D-glucose, while 2-fluoro-2-deoxy-D-glucose with 2-chloro-2-deoxy-D-glucose induced a more potent feeding than 2-deoxyglucose. Glucosamine also induced hyperglycaemia, but did not affect plasma insulin. Activity of glucose, sensitive neurons in the lateral hypothalamus was increased by electro-osmotic application of 2-deoxyglucose or glucosamine, and the reciprocity was observed on neurons of the ventromedial hypothalamus. One-aminoglucose (beta-D-glucopyranosylamine), which is an aminoglucose analogue modified on C-1, increased meal size and more potently prolonged the duration of the meal compared to 1-deoxyglucose (1,5-anhydroglucitol). Together with the behavioural and structural characteristics of glucose analogues, a hydroxyl group on C-1 or C-2 is involved in feeding elicitation. The magnitude of the effect can be partly explained by the chemical concept of 'inductive effect'.