O. Egeler et al., Modulation of lipogenic enzymes, fatty acid synthase and Delta(9)-desaturase, in relation to migration in the western sandpiper (Calidris mauri), J COMP PH B, 170(2), 2000, pp. 169-174
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences",Physiology
Journal title
JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTALPHYSIOLOGY
Long-distance migration in birds is characterized physiologically by period
s of rapid fattening and lipogenesis, and increased desaturation of fatty a
cids stored in adipose tissue. We investigated seasonal, age- and sex-relat
ed differences in activities of two lipogenic enzymes, fatty acid synthase
and Delta(9)-desaturase, in relation to migration in the small, Arctic-nest
ing western sandpiper (Calidris mauri). Migration, and associated lipogenes
is and fattening, involved marked upregulation of these enzymes in this spe
cies. However, this increase in enzyme activity was only seen in actively m
igrating birds during spring migration, when fatty acid synthase and Delta(
9)-desaturase levels increased by 53% and 113%, respectively, compared to I
ron-migrating birds. There was no change in fatty acid synthase enzyme acti
vity during the premigration period, even though body mass of adult birds i
ncreased significantly during this period. Similarly, there was no increase
in Delta(9)-desaturase activity during premigration, despite the fact that
birds increase the proportion of monounsaturated fatty acids in their fat
stores at this time. We suggest that upregulation of lipogenic enzymes is r
equired to support high rates of mass gain (0.4 g day(-1)) during short (1-
4 day) periods at stop-over sites. However, slower rates of mass gain (0.09
g day(-1)) over several weeks prior to migration can be achieved without a
ny increase in tissue-specific enzyme activity.