AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 4 882-R890, Copyright © 1991 by American Physiological Society
Insulin sensitivity and liver insulin receptor structure in ducks from two genera
T. Constans, B. Chevalier, M. Derouet and J. Simon
Station de Recherches Avicoles, Institut National de la Recherche Agronomique, Nouzilly, France.
Insulin sensitivity and liver insulin receptor structure were studied in
5-wk-old ducks from two genera (Muscovy and Pekin). In the fasting state,
both duck types were equally resistant to exogenous insulin compared with
chicken. Despite the low potency of duck insulin, the number of insulin
receptors was lower in Muscovy duck and similar in Pekin duck and chicken
liver membranes. After 125I-insulin cross-linking, the size of the
alpha-subunit of the receptors from the three species was 135,000. Wheat
germ agglutinin-purified receptors from the three species were contaminated
by an active and unusual adenosinetriphosphatase (ATPase) contaminant
(highest activity in Muscovy duck). Sequential purification of solubilized
receptor from both duck types on lentil and then wheat germ agglutinin
lectins led to a fraction of receptors very poor in ATPase activity that
exhibited a beta-subunit size (95,000) and tyrosine kinase activity similar
to those of ATPase-free chicken insulin receptors. Therefore the ducks from
the two genera exhibit an alpha-beta-structure for liver insulin receptors
and a clear difference in the number of liver insulin receptors. Their
sensitivity to insulin is, however, similarly decreased compared with
chicken.
