Biomedical subjects

S Rodríguez-Cuenca

Publications and source records attributed to S Rodríguez-Cuenca.

5 recordsLinked to original sources

PubMed2006

Expression of mitochondrial biogenesis-signaling factors in brown adipocytes is influenced specifically by 17beta-estradiol, testosterone, and progesterone.

Control of mitochondrial biogenesis in brown adipose tissue (BAT), as part of the thermogenesis program, is a complex process that requires the integration of multiple transcription factors to orchestrate mitochondrial and nuclear gene expression. Despite the knowledge of the role of sex hormones on BAT physiology, little is known about the effect of these hormones on the mitochondrial biogenic program. The aim of this study was to determine the effect of testosterone, 17beta-estradiol, and progesterone on the expression of nuclear factors involved in the control of mitochondrial biogenesis and thermogenic function such as ppargamma, pgc1alpha, nrf1, gabpa, and tfam, and also an inhibitor of PI3K-Akt pathway, recently found to be involved in the control of mitochondrial recruitment (pten). For this purpose, an in vitro assay using cell-cultured brown adipocytes was used to address the role of steroid hormones, progesterone, testosterone, and 17beta-estradiol on the mRNA expression of these factors by real-time PCR. Thus 17beta-estradiol seemed to exert a dual effect, activating the PI3K-Akt pathway by inhibiting pten mRNA expression and also inhibiting nrf1 and tfam mRNA expression. Progesterone seemed to positively stimulate mitochondriogenesis and BAT differentiation by increasing the mRNA expression of the gabpa-tfam axis and ppargamma, respectively, but also exerted a negative output by increasing pten mRNA levels. Finally, testosterone inhibited the transcription of pgc1alpha, the master factor involved in UCP1 expression and mitochondrial biogenesis. In conclusion, our results support the idea that sex hormones have direct effects on different mediators of the mitochondriogenesis program.

Adipocytes, Brown↗

PubMed2006

Sex steroid receptor expression in different adipose depots is modified during midpregnancy.

Sex hormone signalling is key in the understanding of adipose tissue metabolism during pregnancy. Sex hormones play an important role in adipose tissue metabolism by activating specific receptors that alter several steps of lipolysis and lipogenesis. We analyze steroid receptor mRNA levels in different rat adipose depots and mammary fat pad, as well as the sex hormone profile during midpregnancy, coinciding with the placentation process. Thus, progesterone and estradiol plasma levels were increased as well as testosterone levels. This hormonal profile was accompanied by low glucose to insulin ratio. PR-B, ERalpha and AR receptor densities during midpregnancy were dependent on adipose depot location. In mammary fat pad, the mRNA levels of sex hormone receptors were correlated with the growth of the depot. These results demonstrate that sex steroid hormone receptor mRNA expression during midpregnancy is tissue-specific. Our results agree with the idea that the increased estrogenic and androgenic signalling could be addressed to reducing the lipogenic state in early pregnancy exerted mainly by progesterone and to prepare adipose tissue for the beginning of the catabolic phase in late pregnancy in a depot-specific manner.

Adipose Tissue↗

PubMed2003

Gender- and site-related effects on lipolytic capacity of rat white adipose tissue.

Gender- and site-related differences in the lipolytic capacity, at the different steps of the adrenergic pathway, in gonadal and inguinal white adipose tissue (WAT), were assessed by studying alpha2A-adrenergic receptor (AR), beta3-AR and hormone-sensitive lipase (HSL) protein levels, and by determining the lipolytic response to different agents. Gonadal WAT showed a lower alpha2A/beta3-AR ratio, a greater lipolytic capacity in response to AR agonists, and higher HSL activity and protein levels than inguinal WAT. In female rats, we found greater alpha2A-AR protein levels and alpha2A/beta3-AR ratio compared to their male counterparts, but, on the other hand, a higher lipolytic response to beta-AR agonists and a greater lipolytic capacity at the postreceptor level, including a more activated HSL protein. Thus, the lipolytic capacity was clearly higher in gonadal than in inguinal WAT, at the different steps of the adrenergic pathway studied. Moreover, in both tissues, females showed a greater inhibition of lipolysis via alpha2-AR, which was counteracted by the higher lipolytic capacity at the postreceptor level.

Adipose Tissue↗

PubMed2002

Using the Web to aid biochemists and microbiologists: an example of computer-based learning using PCR as an example.

The aim of this study was two-fold: to make available to the medical community a fast, efficient tool for troubleshooting PCR problems, and to demonstrate that hypermedia allow one to approach this kind of problem in a new, more useful way. The Web provides access to an enormous amount of information in the medical area, and in particular enables troubleshooting of new techniques in the medical laboratory. Currently it is possible to find textual information but it is not always easy to find hypermedia information. In many cases authors change only the means of dissemination of a book or paper to the Web, but do not adapt the information to the features of this new medium. The prototype of our hypermedia application was developed using Director and Flash programs (Macromedia), the application was developed from a decision tree built as a result of information compiled from expert PCR users and the existing literature. It was implemented on a website using Dreamweaver (Macromedia). The usefulness and possibilities of this application have been tested with physicians, medical laboratory technicians, and health science students, and have been proven to be more effective than traditional methods, both in education processes and in helping researchers and medical laboratory technicians in their daily work. The advance and popularization of the Internet in the medical profession requires information on the Web to adapt to the advantages offered by hypermedia. This new step must be taken, and the Web must offer medical users not only a different medium of information distribution but also a new way of handling and obtaining information.

Biochemistry↗

PubMed2001

Sexual dimorphism in the adrenergic control of rat brown adipose tissue response to overfeeding.

Gender-related differences in the brown adipose tissue (BAT) response to overfeeding rats on a cafeteria diet were studied by assessing the balance between the expression of beta-adrenoceptors (beta1-, beta2-, beta3-AR) and alpha2A-AR and their relation to the expression of uncoupling proteins (UCP1, UCP2, UCP3). Cafeteria diet feeding for 15 days, which involved a similar degree of hyperphagia in both sexes, led to a greater body weight excess in females than in males and a lower activation of thermogenesis. Gender-related differences were found for different adrenoceptor expression and protein levels, which might explain, in part, sex differences in the thermogenic parameters. The lower expression of alpha2A-AR in females than in males could be responsible for the higher expression of UCP1 and thermogenic capacity under non-hyperphagic conditions. However, in a situation of high adrenergic stimulation--as occurs with overfeeding--as there is a preferential recruitment of the beta3-AR by noradrenaline compared with other adrenergic receptors, the higher levels of beta3-AR in males rats than in females could be responsible for the greater thermogenic capacity and the lesser weight gain in males. Thus, the alpha2/beta3 balance in BAT could be a key in the thermogenic control.

Adipose Tissue, Brown↗