Made available in DSpace on 2014-12-17T15:36:52Z (GMT). No. of bitstreams: 1 MarcioVR.pdf: 229432 bytes, checksum: 1ee93b8bd1e9e53f934d759c8f562466 (MD5) Previous issue date: 2008-03-31 / Many behavioral and biological variables of animals are expressed in the form of biological rhytms, down by the Circadian Timing System, that synchronize them with the environment from external stimuli such as light. One of them is the secretion profile of most circulating hormones regulated by the hypothalamuspirtuitary axis, which controls functions essential for the survival and reproduction of organisms. The sag?i, Callithrix jacchus, one of the most studied species about their endocrine physiology, is an appropriate subject for evaluating the profile of plasma prolactin and cortisol of adult males and females born in captivity throughout the year. Three male and two adult femelas were housed individually and subjected to natural environmental conditions over two years. Blood samples were used to measure the circulating levels of both hormones by methods radioimmunoassay (RIA) and immunoassay (ELISA), respectively. The analysis during the year of the plasmatic values of both hormones test was performed by ANOVA for repeated measures, the correlation of Spearman, and the test of Friedman and Student's t-test. The levels of prolactin in plasma were higher during the months in which there is a greater incidence of births of baby in the colony, possibly serving for modulating the expression of the behavior of parental care in both sexes. The plasma cortisol showed a lift in anticipation of the station with the highest birth rate and may be associated with the preparation of individual participation in caring for the baby, and also with the establishment of emotional bond between reproductive partners. Thus, this study shows that, despite the variations observed in the environment in which the animals live, plasma levels of prolactin and cortisol vary little throughout the year. / Muitas vari?veis biol?gicas e comportamentais dos animais se expressam sob a forma de ritmos biol?gicos, determinadas pelo Sistema de Temporiza??o Circadiana, que as sincronizam com o ambiente a partir de est?mulos externos, com a luz. Uma delas ? o perfil de secre??o da maioria dos horm?nios circulantes regulado pelo eixo Hipot?lamo-Hipofis?rio, que control fun??es essenciais para a sobreviv?ncia e a reprodu??o dos organismos. O sag?i, Callithrix jacchus, uma das esp?cies mais estudadas quanto ? sua fisiologia end?crina, ? um sujeito adequado para a avalia??o do perfil plasm?tico de prolactina e cortisol de machos e f?meas adultas nascidos em cativeiro ao lonto do ano. Tr?s machos e duas f?meas adultas foram alojados individualmente e submetidos ?s condi??es ambientais naturais durante dois anos. Amostras de sangue foram usadas para dosar os n?veis circulantes de ambos os horm?nios pelos m?todos Radioimunoensaio (RIA) e Imunoenzim?tico (ELISA), respectivamente. A an?lise ao longo do ano dos valores plasm?ticos de ambos os horm?nios foi realizada pelo teste de ANOVA para Medidas Repetidas, pela correla??o de Spearman, e pelos testes de Friedman e t de Student. Os n?veis de prolactina no plasma se mostraram mais elevados durante os meses nos quais h? uma maior ocorr?ncia de nascimentos de filhotes na col?nia, servindo possivelmente para modular a express?o do comportamento de cuidado parental em ambos os sexos. O cortisol plasm?tico mostrou uma eleva??o em antecipa??o ? esta??o com maior natalidade, podendo estar associada com a prepara??o do indiv?duo para participa??o no cuidado aos filhotes, e tamb?m com o estabelecimento de la?o afetivo entre os parceiros reprodutivos. Assim, o presente estudo mostra que, apesar das varia??es observadas no ambiente no qual os animais vivem, os n?veis plasm?ticos de prolactina e cortisol oscilam pouco ao longo do ano.