Estradiol and osmolality: Behavioral responses and central pathways

- EB treatment of OVX rats affects behavioral and CNS responses to osmotic challenges.
- Hyperosmolality: EB elicits rapid-onset water drinking and decreases CNS activity.
- Hypo-osmolality: EB does not affect salt intake but blunts associated water intake.
- Hypo-osmolality: activation in SFO is blunted in females but independent of EB.
- EB effects on responses to osmotic challenges depend on challenge and on CNS area.

Regulation of appropriate osmolality of body fluid is critical for survival, yet there are sex differences in compensatory responses to osmotic challenges. Few studies have focused on the role of sex hormones such as estradiol in behavioral responses to increases or decreases in systemic osmolality, and even fewer studies have investigated whether central actions of estrogens contribute to these responses. This overview integrates findings from a series of ongoing and completed experiments conducted in my laboratory to assess estradiol effects on water and NaCl intake in response to osmotic challenges, and on activity in central pathways that mediate such responses.