Depressed Progesterone Accumulation by the Brain and Peripheral Tissues of Diabetic C57BL/KsJ Mice: Normalization by Estrogen Therapy

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Abstract
The effects of diabetes on the uptake and incorporation of 3H-progesterone (P) in various brain areas and peripheral tissues were analyzed in C57BL/KsJ mice. Littermate control (+/?) and diabetic (db/db) mice were pulse-treated (60) min with 10 µCi of 3H-P at either 8 or 16 weeks of age. Subsequently, the peripheral tissues and brains were dissected, weighed, digested and the amount of incorporated 3H-P assessed. The pituitary, amygdala, septum and hypothalamus were found to concentrate the highest levels of 3H-P of all the brain areas examined. The brain areas of 16-week-old (+/?) mice accumulated higher concentrations of 3H-P than the comparable 8-week-old brain tissues. In addition, all the brain areas of 8-week-old (db/db) mice accumulated equal or more 3H-P than the comparable (+/?) brains. By 16 weeks of age, however, the 3H-P accumulation rate was significantly higher in all brain areas of (+/?), as compared to (db/db), mice. Of the peripheral tissues examined, the ovary, uterus, pancreas, kidney and mesometrial fat pad consistently exhibited the highest rates of 3H-P accumulation in both (+/?) and (db/db) mice. By 16 weeks of age, all peripheral tissues of (+/?) mice exhibited greater accumulation rates of 3H-P than the comparable (db/db) tissues. Following 4 days of estradiol treatment (10 µg/day s.c), the 3H-P accumulation rates in 16-week-old (+/?) and (db/db) brain were essentially equal. Only the hypothalamus, septum and amygdala of the (db/db) mice failed to normalize to (+/?) levels following estradiol treatment. In a similar manner, the pancreas, uterus, ovary and fat of (db/db) mice exhibited 3H-P accumulation rates similar to those of (+/?) mice following estradiol treatment. These data indicate that estradiol therapy effectively normalizes the normal age- and diabetes-related declines in brain and peripheral tissue sensitivity and/or responsitivity to progesterone in C57BL/KsJ mice.