Synergistic Effects of Insulin and Thyroxine on the Differentiation and Proliferation of Epithelial Cells of Suckling Mouse Small Intestine

Abstract

The interactions between insulin, cortisone and thyroxine on the functional maturation of the small intestine were investigated. 8-day-old suckling mice received one injection/day during 3 days of a single hormone or of the following hormonal combinations: insulin plus cortisone or insulin plus thyroxine. The differentiation of intestinal epithelial cells was evaluated by measuring brush border membrane hydrolytic activities and proliferation by establishing the mitotic index and ³H-thymidine incorporation into DNA. The effects of cortisone and insulin on enterocyte’s differentiation are additive. Thyroxine accelerates the differentiation and has a limited action on cell proliferation. Insulin exerts a sustained effect on these two aspects of the intestinal maturation and, furthermore, acts in synergism with thyroxine. It appears that insulin, cortisone and thyroxine have their own specific effect on differentiation and proliferation of the epithelial cells and that these three hormones act in cooperation to induce the maturation of the suckling mouse small intestine during postnatal development.

Perinatal development of the small intestine of the sheep

“…In the sheep fetus the adrenal produces cortisol in response to hypophyseal ACTH from about 120 days onwards (Wintour, 1984). Plasma cortisol concentrations reach their maximum levels prior to birth, and at birth are still much higher than those in the adult (see Nathanielsz, 1976 (Heyman et al, 1984 ;Guiraldes and Hamilton 19811, thyroxine (see Yeh and Moog, 1977), insulin (Malo and Menard, 1983 ;Arsenault and Menard, 1984), cortisol (Herbst and Sunshine, 1969 …”

Polyamine Concentration in Rat Milk and Food, Human Milk, and Infant Formulas1

“…cific protein absorption ceases ("gut closure"). Various attempts have been made to influence this development sequence (5)(6)(7)(8)(9)(10)(11)(12). Whereas various hormones or local mediators have been shown to be involved in the regulatory mechanism of intestinal maturation in suckling rodents, the influence of food or food constitutents has been less thoroughly studied.…”

Effect of Oral Insulin on the Development of Small Intestine Carbohydrate Hydrolysis and Absorption in Suckling Rats

“…However, our current and earlier results show insulin unlike hydrocortisone or thyroxin [25,26] leads to increase of intestinal carbohydrate hydrolysis and transport which are high at birth, then decrease (intestinal lactase and free glucose transport (Table 2 and 3)). The same results concerning the lactase activity and free glucose transport have been obtained in suckling rats after subcutaneous administration of insulin [22][23][24][25][26]. Indeed, insulin and/or corticosteroids have no effect on the developmental lactase decline [1, 4.…”

“…Administration of glucocorticoids or thyroids at the critical stage in maturation results in precocious increasing of intestinal α-glycosidase activity and hydrolysis-dependent glucose absorption from maltose and/or saccrose [1,4,7,[11][12][13]23]. However, glucocorticoids have no effect on lactase activity and free glucose transport [11,25].…”

“…However, glucocorticoids have no effect on lactase activity and free glucose transport [11,25]. Obtained and literature data show insulin has the same effect as cortisone and/or thyroxin on the intestinal functions which are low at birth, then increase [22][23][24][25][26][27][28][29][30][31][32]. However, our current and earlier results show insulin unlike hydrocortisone or thyroxin [25,26] leads to increase of intestinal carbohydrate hydrolysis and transport which are high at birth, then decrease (intestinal lactase and free glucose transport (Table 2 and 3)).…”