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Major depression is more prevalent among women than men, and progesterone might be involved in the mechanisms that generate these differences. Progesterone is clinically used for women in several reproductive events, but its antidepressant effect is unclear. Animal studies showed the interference of progesterone on depressive behaviors of rodents, but they are inconclusive, and no study compared different treatment durations. This study investigated the antidepressant effect of low doses of progesterone in male and female rats under acute or chronic administration. Male and female Wistar rats in different phases of the estrous cycle were acutely administered different doses of progesterone (0.0, 0.4. 0.8 and 1.2mg/kg) and tested in the forced swimming test (FST). The lowest dose of progesterone (0.4 mg/kg) was chronically administered during two complete estrous cycles and diestrous II female and male rats were tested in the FST. Progesterone decreased depressive-like behaviors only in chronically treated diestrous II female rats and increased immobility in male rats. This low dose of progesterone did not interfere in the hormonal cycling in female rats. Results also showed that diestrous II female rats had greater immobility than male rats in the FST. The greater immobility of diestrous II female rats shows that rats in this estrous phase present more depressive-like behaviors that may be associated with their lower serum levels of progesterone. We showed that progesterone chronically administered at low doses reverses these depressive-like behaviors and has an antidepressant effect during the diestrous II phase of the estrous cycle.

Progesterone is a neuroactive hormone with non-genomic effects on GABA(A) receptors (GABA(A)R). Changes in the expression of GABA(A)R subunits are related to depressive-like behaviors in rats. Moreover, sex differences and depressive behaviors have been associated with prefrontal brain asymmetry in rodents and humans. Thus, our objective was to investigate the effect of progesterone on the GABA(A)R α1 and γ2 subunits mRNA expression in the right and left prefrontal cortex of diestrus female and male rats exposed to the forced swimming test (FST). Male and female rats (n = 8/group) were randomly selected to receive a daily dose of progesterone (0·4 mg·kg⁻¹) or vehicle, during two complete female estrous cycles (8-10 days). On the experiment day, male rats or diestrus female rats were euthanized 30 min after the FST. Our results showed that progesterone significantly increased the α1 subunit mRNA in both hemispheres of male and female rats. Moreover, there was an inverse correlation between depressive-like behaviors and GABA(A)R α1 subunit mRNA expression in the right hemisphere in female rats. Progesterone decreased the GABA(A)R γ2 mRNA expression only in the left hemisphere of male rats. Therefore, we conclude that the GABA(A) system displays an asymmetric distribution according to sex and that progesterone, at lower doses, presents an antidepressant effect after increasing the GABA(A) R α1 subunit expression in the right prefrontal cortex of female rats.

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INTRODUÇÃO: o consumo de nutrientes antioxidantes por pacientes em hemodiálise é importante, pois a doença renal pode desencadear desequilíbrio oxidativo decorrente da intensa produção de espécies reativas, falhas nos sistemas antioxidantes e retenção do soluto oxidado. OBJETIVO: avaliar a adequação do consumo alimentar de nutrientes antioxidantes por pacientes renais crônicos em hemodiálise. MÉTODOS: o estudo foi desenvolvido com pacientes em tratamento de hemodiálise, afiliados a duas clínicas especializadas em Fortaleza, Ceará, Brasil. Os dados foram coletados por meio de três recordatórios de 24h e tabulados no programa Excel 2007®. Foram realizadas análises qualitativa e quantitativa da ingestão de selênio, zinco, vitamina A, vitamina C e vitamina E. O estudo incluiu 26 homens e 18 mulheres entre 19 e 83 anos de idade. RESULTADOS: encontraram-se médias de ingestão abaixo da EAR (Estimated Average Requeriment) de zinco, vitamina A, C e E e prevalências de risco de inadequação superior a 50% para todos os micronutrientes analisados, exceto o selênio. A ingestão de vitamina E foi inferior a EAR em 100% dos pacientes. CONCLUSÃO: os pacientes renais crônicos em hemodiálise se encontravam com ingestão inadequada de micronutrientes antioxidantes, contribuindo para o aumento do estresse oxidativo.