Cognitive-impairing effects of medroxyprogesterone acetate in the rat: independent and interactive effects across time
- 186 Downloads
The synthetic progestin medroxyprogesterone acetate (MPA), widely used in hormone therapy (HT) and as the contraceptive Depo Provera, is implicated in detrimental cognitive effects in women. Recent evidence in aged ovariectomized (Ovx) rodents shows that short-term MPA treatment impairs cognition and alters the GABAergic system.
Using rats, we evaluated the long-lasting cognitive and GABAergic effects of MPA administered in young adulthood (Early-MPA), modeling contraception, and how this early exposure interacts with later MPA treatment (Late-MPA), modeling HT.
Early-MPA treatment involved weekly anti-ovulatory MPA injections (3.5 mg) from 4 to 8 months of age in ovary-intact rats. At 10 months old, rats were Ovx and weekly MPA injections were re-initiated and continued throughout testing for Late-MPA treatment.
On the water radial-arm maze, all MPA-treated groups showed working memory impairment compared to Controls (p < 0.05); Early + Late-MPA rats were impaired on multiple dimensions of working memory (p < 0.05). On the Morris maze, Late-MPA rats showed greater overnight forgetting compared to Controls (p < 0.05). At study conclusion, MPA was detected in serum in all MPA-treated groups except Early-MPA, confirming treatment and clearance from serum in Early-MPA rats. In animals with detectable serum MPA, higher MPA levels were associated with less dorsal-hippocampal glutamic acid decarboxylase, the synthesizing enzyme for GABA (p = 0.0059).
Findings suggest that MPA treatment leads to long-lasting cognitive impairments in the rodent, even in the absence of circulating MPA in animals given prior MPA treatment, which may relate to the GABAergic system. Further research defining the parameters of the negative impact of this widely used progestin on brain and cognition is warranted.
KeywordsHormone therapy Contraceptive Cognition Progestins Menopause Aging Learning and memory
- (2006) Depo Provera Prescribing Information. In: Pfizer for Professionals. Available at http://media.pfizer.com/files/products/uspi_depo_provera_contraceptive.pdf. Accessed 28 Jan 2011
- (2009) Prempro Prescribing Information. In: Pfizer for Professionals. Available at http://www.pfizerpro.com/content/showlabeling.asp?id-133. Accessed 28 Jan 2011
- Gabriel A, Fahim G (2005) Do depot medroxyprogesterone acetate contraceptive injections cause mood changes and memory impairment? Prim Psychiatry 12:59–60Google Scholar
- Keppel G, Wickens TD (2004) Design and analysis: a researcher’s handbook, 4th edn. Pearson Prentice Hall, Upper Saddle RiverGoogle Scholar
- Mosher WD, Martinez GM, Chandra A, Abma JC, Willson SJ (2004) Use of contraception and use of family planning services in the United States: 1982–2002. Adv Data (350):1–36Google Scholar
- Paxinos G, Watson C (1998) The rat brain in stereotaxic coordinates, 4th edn. Academic, New YorkGoogle Scholar
- Rasband W (1997–2004) Image J National Institute of Health, Bethesda, Maryland, USA. Available at http://rsb.info.nih.gov/ij/
- Shumaker SA, Legault C, Rapp SR, Thal L, Wallace RB, Ockene JK, Hendrix SL, Jones BN 3rd, Assaf AR, Jackson RD, Kotchen JM, Wassertheil-Smoller S, Wactawski-Wende J (2003) Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women’s Health Initiative Memory Study: a randomized controlled trial. JAMA 289:2651–2662PubMedCrossRefGoogle Scholar
- Shumaker SA, Legault C, Kuller L, Rapp SR, Thal L, Lane DS, Fillit H, Stefanick ML, Hendrix SL, Lewis CE, Masaki K, Coker LH (2004) Conjugated equine estrogens and incidence of probable dementia and mild cognitive impairment in postmenopausal women: Women’s Health Initiative Memory Study. JAMA 291:2947–2958PubMedCrossRefGoogle Scholar
- Sun WL, Luine VN, Zhou L, Wu HB, Weierstall KM, Jenab S, Quiniones-Jenab V (2010) Acute progesterone treatment impairs spatial working memory in intact male and female rats. Ethn Dis 20(S1):83–87Google Scholar