Rapid stimulation of intestinal D-glucose transport in teleosts by 17 a - methyltestosterone

testosterone (MT) on transmural transport of 0.5 mM D-[~H]-glucose across upper intestine of the herbivorous teleost, Or-eochromis mossambicus, were examined using modified Ussing chambers containing a physiological saline. Treatment tissues were preincubated with MT on the serosal surface for 30 min, while control tissues were incubated with an equivalent volume of 70 % ethanol. Stimulation of mucosal-to-serosal D-ghCOse flux (Jm+) by MT was dose dependent with maximal transport enhancement at 15 ng MT/ml saline (215 % of control) and inhibition of sugar transfer occurring at 50 ng MT/ml (60 % of control). Hormone treatment (15 ng MT/ml) significantly (P < 0.05) increased net transmural D-glucose flux (Jnet; control = 0.36 $- 0.084, MT = 0.75 t 0.130 nmol cm-* * min-‘) as a result of enhancing Jm-,S (control = 0.52 t 0.048; MT = 0.91 t 0.078 nmol. cm- * l- ’ ) without having a significant effect on th