Behavioral effects of endogenous or exogenous estradiol and progesterone on cocaine sensitization in female rats

Cocaine sensitization is a marker for some facets of addiction, is greater in female rats, and may be influenced by their sex hormones. We compared the modulatory effects of endogenous or exogenous estradiol and progesterone on cocaine-induced behavioral sensitization in 106 female rats. Ovariectomized female rats received progesterone (0.5 mg/mL), estradiol (0.05 mg/mL), progesterone plus estradiol, or the oil vehicle. Sham-operated control females received oil. Control and acute subgroups received injections of saline, while the repeated group received cocaine (15 mg/kg, ip) for 8 days. After 10 days, the acute and repeated groups received a challenge dose of cocaine, after which locomotion and stereotypy were monitored. The estrous cycle phase was evaluated and blood was collected to verify hormone levels. Repeated cocaine treatment induced overall behavioral sensitization in female rats, with increased locomotion and stereotypies. In detailed analysis, ovariectomized rats showed no locomotor sensitization; however, the sensitization of stereotypies was maintained. Only females with endogenous estradiol and progesterone demonstrated increased locomotor activity after cocaine challenge. Estradiol replacement enhanced stereotyped behaviors after repeated cocaine administration. Cocaine sensitization of stereotyped behaviors in female rats was reduced after progesterone replacement, either alone or concomitant with estradiol. The behavioral responses (locomotion and stereotypy) to cocaine were affected differently, depending on whether the female hormones were of an endogenous or exogenous origin. Therefore, hormonal cycling appears to be an important factor in the sensitization of females. Although estradiol increases the risk of cocaine sensitization, progesterone warrants further study as a pharmacological treatment in the prevention of psychostimulant abuse.

Plasma concentration of progesterone and 17ß-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle

Plasma concentration of progesterone and 17β-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle. The agouti is a game animal that have been raised in captivity for conservation and sustainability purposes. However, the management of wild animals in an intensive breeding system requires an assertive knowledge of its reproductive parameters, one of the most important features for production improvement. Besides, little information is available regarding changes in reproductive hormone profiles in agouti. The objective of this study was to evaluate the hormonal profile of progesterone and 17β-estradiol during the estrous cycle of the agouti (Dasyprocta prymnolopha). The hormones were analyzed by radioimmunoassay. Blood samples were collected without sedation twice a week. The concentrations of progesterone were as follows: proestrus 0.78+0.39ng/ml, estrus 2.83+2.34ng/ml, metestrus 1.49+1.24ng/ml, diestrus 3.71+1.48ng/ml. In the estrous phase, an increase in the progesterone level was observed during a period of 24h. The average 17 β-estradiol levels were as follows: proestrus 2 030.98+961.00pg/ml, estrus 1 910.56+650.54pg/ml, metestrus 1 724.83+767.28pg/ml, diestrus 1 939.94+725.29pg/ml. The current results suggest that the progesterone plasma concentration during the estrous cycle in the agouti has a similar increasing, stabilizing and decreasing pattern, as in domestic mammals. Agoutis have two phases of follicular development, as two periods of 17β-estradiol peaks were observed, the first one in the metestrus and the second during the proestrus. Spontaneous ovulation seems to occur after the progesterone peak, possibly indicating that this hormone is associated with the ovulatory process. A more detailed investigation is needed for better understanding of how progesterone influences ovulation. Studies on the involvement of progesterone in follicular rupture can be carried out, using steroid biosynthesis inhibitors and observing the effect of this hormone on ovarian activity of proteolytic enzymes in the follicular wall. Rev. Biol. Trop. 59 (1): 29-35. Epub 2011 March 01.

El conocimiento de los procesos reproductivos de especies de importancia económica local son indispensables para apoyar su producción en cautiverio y garantizar su manejo sostenible. El objetivo del presente trabajo fue evaluar los niveles hormonales de progesterona y 17β-estradiol durante el ciclo estral en agutí (Dasyprocta prymnolopha). La recolección de sangre se realizó dos veces por semana, sin sedación. Las hormonas fueron analizadas por radioinmunoanálisis. Los niveles de progesterona fueron los siguientes: proestro 0.78+0.39ng/ml, estro 2.83+2.34ng/ml, metaestro 1.49+1.24ng/ml y diestro 3.71+1.48ng/ml. En el estro se observó un aumento de los niveles de progesterona durante un periodo de 24h. Los niveles de 17 β-estradiol fueron los siguientes: proestro 2 030.98+961.00pg/ml, estro 1 910.56+650.54pg/ml, metaesto 1 724.83+767.28pg/ml y diestro 1 939.94+725.29pg/ ml. Los resultados encontrados sugieren que los niveles plasmáticos de progesterona durante el ciclo estral en agutí siguen un patrón de aumento, estabilización y diminución, tal como en los mamíferos domésticos. Agutí tienen dos etapas de desarrollo folicular, puesto que se observaron dos altos valores de 17β-estradiol, el primero en el metaestro y el segundo durante el proestro. La ovulación espontánea ocurre posiblemente después del aumento de la progesterona, indicando que esta hormona posiblemente está asociada con el proceso ovulatorio. Es necesario desarrollar un estudio más detallado para mejorar la comprensión del papel de la progesterona en la ovulación. Algunos estudios de la participación de la progesterona en la ruptura folicular se pueden realizar utilizando inhibidores de la biosíntesis de esteroides y observar el efecto de esta hormona sobre la actividad de las enzimas proteolíticas en la pared folicular.

Efeitos da endotelina-1 sobre a esteroidogênese e o crescimento celular em cultura de células da granulosa de bovinos / Endothelin-1 effects on steroidogenesis and cellular growth of bovine granulosa cells culture

Além do controle neuroendócrino do eixo hipotalâmico-hipofisáriogonadal existem fatores autócrinos e parácrinos que controlam o crescimento, seleção e ovulação nos mamíferos. Estes fatores ainda não estão bem estabelecidos. Objetivando analisar as variações nas concentrações plasmáticas da endotelina-1 em um ciclo estral bovino e seus efeitos sobre o cultivo de células da granulosa, foram analisadas amostras plasmáticas de 5 dias (0, 1, 3, 7 e 13) de um ciclo estral, tendo como base o dia da ovulação (dia 0) e 3 horas (8, 13 e 16) do 14º dia do ciclo. As variações nas concentrações plasmáticas de endotelina-1 não foram significativas para os dias assim como para as horas do dia analisado. Células da granulosa obtidas de folículos antrais foram cultivadas durante 48 horas com diferentes concentrações de endotelina. Os resultados demonstraram que a endotelina atua de maneira dosedependente estimulando a produção de progesterona e inibindo o crescimento celular.

Besides the neuroendocrine control of the hypotalamic-hypophisarygonodal axis there are autocrines and paracrines factors that control the growth, selection and ovulation in the mammals. These factors are not well established yet. Aiming to analyze the variations in the endotelin-1plasmatic concentrations in a bovine estral cycle and their effects on the culture of granulosa cells, plasma samples of 5 days (0,1,3,7 and 13) from an estral cycle have been analyzed, having as basis the ovulation day (day 0) and 3 hours (8,13,16) of the fourteenth day of the cycle. The variations in the endothelin-1 concentrations were not significant for the days as well as for the hours of the analyzed day. Granulosa cells obtained from antral follicles were cultivated during 24 hours with different concentrations of endothelin. The results demonstrated that the endothelin-1 acts in a dose-dependent manner stimulating the production of progesterone and inhibiting the cellular growth.

Actividad ovárica del tepezcuintle Agouti paca (Rodentia: Agoutidae) en cautiverio / Ovarian activity of Agouti paca (Rodentia: Agoutidae) under captivity

The ovarian activity of Agouti paca was characterized by hormonal profiles and ovarian structures. Samples of blood were taken from eight females (seven adults and one juvenile) at the breeding grounds of the Facultad de Medicina Veterinaria y Zootecnia in Yucatsn, Mexico. Sampling lasted approximately two months and was done every three and six days. Blood was collected from anesthetized animals, and the levels of progesterone (P4) and 17 beta estradiol (E2) were analized by radioimmunoassay technique. Macroscopic and microscopic analyses were carried out in ovaries of dead animals. The estrous cycle lasted 29+/-8.4 days, levels of 1.61+/-0.65 ng/ml for P4 and 39+/-24 pg/ml for E2 were observed for a follicular phase, 6.18+/-3.70 ng/ml and 29+/-16 pg/ml for P4 and E2 respectively in the luteal phase. Statistically significant differences were found between phases for P4 but not for E2. The presence of extragonadal steroids with levels of P4 of 1.9+/-0.77 ng/ml and E2 of 22+/-17 pg/ml were observed, which are not produced by the effects of managing stress. The changes in the levels of P4 during the cycle are indicators of luteal activity, with the intersticial tissue acting probably as active steroids-producing gland. Follicular growth was observed during the entire cycle.

Se caracterizó la actividad ovárica de A. paca por medio de perfiles hormonales y estructuras ováricas. Se muestrearon ocho hembras (siete adultas y una juvenil) en el criadero de la Facultad de Medicina Veterinaria y Zootecnia en el estado de Yucatán, México, durante aproximadamente dos meses. Se recolectaron muestras sanguíneas cada 3 y 6 días en animales anestesiados. Se estimaron los niveles de progesterona (P4) y 17 beta estradiol (E2) sanguíneos por radioinmunoanálisis. Las estructuras ováricas de animales muertos durante el periodo de muestreo fueron analizadas macro y microscópicamente. El ciclo ovárico duró 29±8.4 días, con niveles de 1.61±0.65 ng/ml para P4 y de 39±24 pg/ml para E2 durante la fase folicular, y de 6.18±3.70 ng/ml y 29±16 pg/ml para P4 y E2 respectivamente, en la fase luteal. Hubo diferencias (p<0.05) en los niveles de P4 entre las fases folicular y luteal, no así para E2. Se detectó la presencia de esteroides extragonadales, con niveles de 1.9±0.77 ng/ ml para P4 y de 22±17 pg/ml para E2, los cuales no son secretados por efecto del estrés por manejo. Los cambios en los niveles de P4 durante el ciclo son indicadores de actividad luteal, funcionando el tejido intersticial probablemente como una glándula productora de esteroides. De igual forma se observó que el crecimiento folicular ocurre durante todo el ciclo.