New research by Dr. Liisa Galea…suggests the form of estrogens used in hormone therapy and previous motherhood could be critical to explain why HT has variable effects. Research in women, and Dr. Galea’s research in animals, shows that one form of estrogens, called estradiol, which is the predominant form of estrogens in young women, had beneficial effects, while estrone, which is the predominant form of estrogens in older women, did not. Furthermore, the effects of estrone also depended on whether the rats had experienced motherhood: estrone-based HT impaired learning in middle-aged rats that were mothers, while it improved learning in rats that were not….
“Our most recent research shows that previous motherhood alters cognition and neuroplasticity in response to hormone therapy, demonstrating that motherhood permanently alters the brain” says Dr. Liisa Galea.
Dr. Liisa Galea is interested in how hormones affect brain and behaviour. Hormone therapy (HT) has been shown to have variable effects on brain function and Dr. Galea noted that one factor that had not received much attention was the form of estrogens used in HT. There are three forms of estrogens: estradiol, estrone and estriol. Estradiol is the most potent of estrogens, and it is the predominant form in young women, while estrone is a weaker estrogen and is the predominant form in post-menopausal women. A systematic review of the published scientific literature indicates that estradiol-based HT may have more beneficial effects, while estrone-based HTs may have more detrimental effect on cognition and dementia risk in women…
…Dr. Galea’s previous research had shown that motherhood causes changes in the architecture of connections in the hippocampus, so her team investigated whether the different forms of estrogens could have different effects on rats that had experienced motherhood once (primiparous rats) and on those who had not (nulliparous rats). They found that estrone-based HT improved learning in middle-aged nulliparous rats, but impaired learning in primiparous rats of the same age. These primiparous rats also showed a reduction in neurogenesis and zif268, a protein involved in neuroplasticity in the hippocampus.
As estrone is a component of the most common form of HT prescribed for women in the US, these findings could have implications for the treatment of age-related neurodegenerative disorders in women.
“Hormones have a profound impact on our mind. Pregnancy and motherhood are life-changing events resulting in marked alterations in the psychology and physiology of a woman. Our results argue that these factors should be taken into account when treating brain disorders in women” concludes Dr. Liisa Galea.
Questions relating to procreation are more scientific than social – just as the opposite is true of questions about religious belief, even though the hypothetical average individual has been taught otherwise.
I find it all interesting because I not only never had any interest in becoming a father, I had a vasectomy quite young. Of course, living, then, in a good Catholic state that simple out-patient procedure was illegal along with contraception. My urologist asked me to swear I would tell anyone who asked that I went to Rhode Island to have it done. 🙂