Energy metabolism and substrate oxidation in acromegaly O'Sullivan, Anthony en_US Kelly, John en_US Hoffman, David en_US Baxter, R en_US Ho, K.K.Y. en_US 2021-11-25T14:26:08Z 2021-11-25T14:26:08Z 1995 en_US
dc.description.abstract Short term GH administration increases lipid breakdown and oxidation (lipidox) and reduces glucose uptake and carbohydrate oxidation (CHOox). It is not clear whether similar shifts in substrate oxidation occur in acromegaly, and our aim was to investigate this. Using indirect calorimetry, we compared energy expenditure, CHOox, and lipidox in 20 acromegalic patients and 20 normal subjects pair-matched for sex, age, height, and weight. Investigations were performed in the basal state (12-h fast) and during a 75-g oral glucose tolerance test (OGTT). Acromegalic patients had significantly higher fasting glucose levels and greater glucose and insulin responses during an OGTT than normal subjects. Fasting nonesterified free fatty acid and insulin-like growth factor (IGF)-binding protein-1 levels were similar in the two groups, and both were acutely suppressed by oral glucose to the same degree. Basal energy expenditure was significantly greater in the acromegalic patients (1682 +/- 49 vs. 1540 +/- 45 Cal/24 h; P < 0.05), who showed a trend toward higher basal CHOox. Oral glucose resulted in a significantly higher rise in energy expenditure in the normal compared to the acromegalic subjects. During the OGTT, CHOox significantly increased in both groups, but rose to a higher level in the acromegalic patients (177 +/- 10 vs. 138 +/- 9 mg/min; P = 0.004). Oral glucose significantly reduced lipidox in both groups, but lipidox was reduced to a significantly lower level in the acromegalic patients (32 +/- 4 vs. 46 +/- 3 mg/min; P = 0.004). In acromegaly, basal CHOox (r = 0.56; P = 0.01) and postglucose CHOox (r = 0.79; P = 0.0001) were both positively correlated to IGF-I, but not to insulin and/or glucose. In normal subjects, postglucose CHOox was positively correlated to IGF- I. In summary, hyperinsulinemia in acromegaly was associated with higher glucose levels and a blunted thermogenic response to glucose, and displayed no relationship to the pattern of substrate oxidation. CHOox was increased, and lipidox was reduced in acromegaly, and the extent of IGF-I elevation was related to CHOox in the basal and postglucose states. We conclude that 1) the chronic effects of GH excess on substrate oxidation differ from the short term effects of GH administration; 2) impaired insulin action in acromegaly extends to effects on energy expenditure; and 3) IGF-I may be an important regulator of substrate oxidation in acromegaly. en_US
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.title Energy metabolism and substrate oxidation in acromegaly en_US
dc.type Journal Article en
dcterms.accessRights open access
dspace.entity.type Publication en_US
unsw.description.notePublic Original inactive link: en_US
unsw.description.publisherStatement Copyright © 1995 by Endocrine Society en_US
unsw.relation.faculty Medicine & Health
unsw.relation.ispartofjournal Journal of Clinical Endocrinology and Metabolism en_US
unsw.relation.ispartofpagefrompageto 486-491 en_US
unsw.relation.ispartofvolume 80 en_US
unsw.relation.originalPublicationAffiliation O'Sullivan, Anthony, Clinical School - St George Hospital, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Kelly, John, Clinical School - St George Hospital, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Hoffman, David, Garvan Institute of Medical Research, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Baxter, R en_US
unsw.relation.originalPublicationAffiliation Ho, K.K.Y., Garvan Institute of Medical Research, Faculty of Medicine, UNSW en_US Clinical School St George Hospital * Garvan Institute *
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