Premium
Administration of 3,5,3'‐triiodothyronine induces a rapid increase in enterocyte lactase‐phlorizin hydrolase activity of young pigs on a low energy intake
Author(s) -
Tivey DR,
Morovat A,
Dauncey MJ
Publication year - 1993
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1993.sp003689
Subject(s) - sucrase , lactase , medicine , endocrinology , triiodothyronine , disaccharidase , enterocyte , maltase , meal , biology , saline , phlorizin , chemistry , small intestine , enzyme , thyroid , glucose transporter , biochemistry , insulin
The rapid increase in plasma concentration of 3,5,3'‐triiodothyronine (T3) which occurs after feeding may invoke changes in lactase‐phlorizin hydrolase (LPH) activity of the small intestine. This hypothesis has been tested in 6‐week‐old pigs living at thermal neutrality (26 degrees C) on a low level of energy intake. Littermate pairs were infused with either saline or T3 at 30 min intervals over a 6 h period, 18‐24 h after the last meal. The activity of LPH in mucosal homogenates increased significantly in test compared with control animals (P < 0.05; T3 37% > saline). This was a specific effect on LPH since there was no effect of T3 on the activity of sucrase‐isomaltase. Further, it could not be attributed to changes in intestinal morphology since there were no differences in crypt depth, villus height or villus area between the two groups. Enzyme‐cytochemical analysis indicated that administration of T3 increases LPH activity at all points along the villus axis, whereas there is no effect on alpha‐glucosidase (combined sucrase‐isomaltase and maltase) activities. These results indicate that there is unlikely to be a simple causal relation between the immediate increase in plasma T3 after feeding and the initial decline in LPH activity observed previously in young pigs living in a cold environment. By contrast, the subsequent increase in LPH activity could be under the direct control of the food‐induced increase in plasma T3 concentration, and the present results suggest a potential role for T3 as an important short‐term homeostatic regulator of LPH in the small intestine.