O objetivo deste trabalho foi verificar a ocorrência de Dioscorea trifida no Brasil e obter informações a respeito da sua distribuição, manejo e diversidade. Para tanto, foram visitados e entrevistados agricultores de 21 comunidades, nos Estados de São Paulo, Santa Catarina, Mato Grosso. Durante as visitas, foram realizadas entrevistas semi-estruturadas visando obter dados sócioeconômicos, de manejo e diversidade da cultura. Cinquenta e um acessos, além de dois acessos adquiridos em feiras no Estado do Amazonas, foram caracterizados por meio de 12 descritores morfológicos. A maioria dos entrevistados era homem (75%) com média de idade de 59,5 anos. Observou-se um número reduzido de jovens e mão de obra disponível para as atividades agrícolas, cerca de três indivíduos por roça. A maior parte dos agricultores (56%) cultiva apenas uma variedade de D. trifida, embora 44% tenham declarado o cultivo de mais de uma variedade, procedimento que visa dar maior garantia de colheita. Vários nomes populares foram observados para D. trifida, sendo cará roxo, a denominação mais utilizada pelos agricultores (43,4%). Os caracteres referentes às túberas, como cor da casca e da polpa, foram os mais relevantes para a distinção dos acessos. Os resultados obtidos poderão colaborar para elaborar estratégias de conservação, tanto ex situ como in situ, dentro da visão de conservação on farm.

The objective of this study was to verify the occurrence of Dioscorea trifida in Brazil and to obtain information concerning its distribution, management and diversity. Farmers from 21 communities were interviewed in the states of São Paulo, Santa Catarina and Mato Grosso. During the visits, semi-structured interviews were conducted to collect socio-economic, management and diversity data for this crop. Fifty-one collected accessions, plus two accessions obtained at local markets of Amazonas, were characterized using 12 morphological traits. Most the interviewed farmers were men (75%) with a mean age of 59.5 years. Just a few young people and labor force were available for agricultural activities, with an average of only three individuals per farm. Most farmers (56%) grew only one variety of D. trifida, although 44% had more than one variety in their fields, which aims to provide greater assurance at harvest. Many popular names were observed for D. trifida, and cará roxo (purple yam) was the name most used by farmers (43.4%). Characters referring to the tuber, such as skin and flesh color, were most relevant for the distinction of the accessions. The results of this study may collaborate to develop strategies for conservation, both ex situ and in situ, within the view of on farm conservation.

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormonereleasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormonereceptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.