Insulin stimulation of the glucose uptake by the thyroid gland of the turtle (Chrysemys dorbigni)... more Insulin stimulation of the glucose uptake by the thyroid gland of the turtle (Chrysemys dorbigni) has been previously reported. The aim of the present study was to examine the influence of different temperatures (6, 25, or 36°C) on this effect. Insulin-stimulated glucose uptake was evident when turtles were acclimated for 15 days at 25" or 36"C, and their glands studied at the respective temperatures. In glands from turtles acclimated at 6"C, this effect was only seen when the preincubation and incubation time was extended from 60 to 300 min. The findings show that in this ectotherm species (1) the insulin effect is temperature dependent, and (2) can be expressed at very low temperature.
The presence of specific insulin binding sites in the thyroid gland of the turtle Chrysemys dorbi... more The presence of specific insulin binding sites in the thyroid gland of the turtle Chrysemys dorbigni has been previously reported. The purpose of the present work was to investigate the probable action of insulin on the uptake of [%]deoxy-D-glucose ([i4C]DG) and ['4C]u-aminoisobutyric acid (['4C]AlB) in turtle (C. dorbigni) thyroid glands in vitro. Thyroid fragments (?40 mg) were incubated at 25" in Krebs-Ringer-bicarbonate buffer containing 0.2 uCi of ['4C]DG or [i4C]AIB without or with bovine insulin at different periods of time. The uptake of [i4C]DG and [14C]AIB increased with incubation time. The presence of insulin (7 x 10m6 M) in the incubation medium during 240 min did not modify the [i4C]DG uptake. However if the thyroid fragments were previously incubated with insulin (60 min) and then incubated (240 min) with the same concentration of the hormone, the [14C]DG uptake was markedly increased. This stimulatory effect of insulin was dose-dependent. In similar experimental conditions, insulin also produced a significant increase in the uptake of ["'CIAIB. Therefore, these findings strongly support the hypothesis that insulin might exert a direct action on the thyroid function. o IW Academic press, IOC.
Insulin stimulation of the glucose uptake by the thyroid gland of the turtle (Chrysemys dorbigni)... more Insulin stimulation of the glucose uptake by the thyroid gland of the turtle (Chrysemys dorbigni) has been previously reported. The aim of the present study was to examine the influence of different temperatures (6, 25, or 36°C) on this effect. Insulin-stimulated glucose uptake was evident when turtles were acclimated for 15 days at 25" or 36"C, and their glands studied at the respective temperatures. In glands from turtles acclimated at 6"C, this effect was only seen when the preincubation and incubation time was extended from 60 to 300 min. The findings show that in this ectotherm species (1) the insulin effect is temperature dependent, and (2) can be expressed at very low temperature.
The presence of specific insulin binding sites in the thyroid gland of the turtle Chrysemys dorbi... more The presence of specific insulin binding sites in the thyroid gland of the turtle Chrysemys dorbigni has been previously reported. The purpose of the present work was to investigate the probable action of insulin on the uptake of [%]deoxy-D-glucose ([i4C]DG) and ['4C]u-aminoisobutyric acid (['4C]AlB) in turtle (C. dorbigni) thyroid glands in vitro. Thyroid fragments (?40 mg) were incubated at 25" in Krebs-Ringer-bicarbonate buffer containing 0.2 uCi of ['4C]DG or [i4C]AIB without or with bovine insulin at different periods of time. The uptake of [i4C]DG and [14C]AIB increased with incubation time. The presence of insulin (7 x 10m6 M) in the incubation medium during 240 min did not modify the [i4C]DG uptake. However if the thyroid fragments were previously incubated with insulin (60 min) and then incubated (240 min) with the same concentration of the hormone, the [14C]DG uptake was markedly increased. This stimulatory effect of insulin was dose-dependent. In similar experimental conditions, insulin also produced a significant increase in the uptake of ["'CIAIB. Therefore, these findings strongly support the hypothesis that insulin might exert a direct action on the thyroid function. o IW Academic press, IOC.
Uploads
Papers by maria marques