Hepatic estrogen receptor in the turtle, Chrysemys picta: partial characterization, seasonal changes and pituitary dependence |
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Authors: | D Riley G J Heisermann R MacPherson I P Callard |
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Abstract: | A hepatic estrogen receptor is described from female turtles, Chrysemys picta. The receptor adheres to DNA after incubation with 3H]estradiol and can be eluted with a linear salt gradient as a single component with an elution maximum of 0.21 M. It is steroid-specific, binding estrogens, but not androgens or progestins. Specific binding saturates between 3 and 7 nM 3H]estradiol-17 beta and Scatchard analysis gave a Kd of 2 X 10(-9) M and a maximal binding capacity of 3.02 fmol/mg protein. Hypophysectomy reduces hepatic estradiol receptor from 70 fmol/g tissue in control animals to non-detectable levels. Growth hormone replacement partially restored the receptor to 36% of control. Significant changes in receptor occur during the ovarian cycle. |
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