Ghrelin, a gut peptide with key actions on food intake and GH secretion, has been recently recognized as potential regulator of reproductive function. Thus, in adult female rats, ghrelin has been proven to modulate GnRH/LH secretion, with predominant inhibitory effects in vivo. We analyze herein potential direct pituitary effects of ghrelin on basal and GnRH-stimulated gonadotropin secretion in prepubertal female rats, and its interplay with ovarian inputs, nitric oxide (NO), and hypothalamic differentiation. In the experimental setting, pituitaries from intact and ovariectomized prepubertal female rats were challenged with ghrelin in vitro and LH secretion was monitored. Our results demonstrate that 1) ghrelin consistently stimulated in vitro pituitary LH secretion under different experimental conditions; 2) the sensitivity to ghrelin, expressed either as the minimal effective dose or the amplitude of the LH response, was modulated by ovarian inputs; 3) the blockade of estrogen action significantly augmented the stimulatory effect of ghrelin; 4) the stimulatory effect of ghrelin on LH secretion required proper NO synthesis; and 5) the ability of ghrelin to elicit LH secretion in vitro was preserved after alteration (masculinization) of brain sexual differentiation. Overall, our present data reinforce the concept that ghrelin participates in the control of LH secretion, with potential stimulatory actions at the pituitary level that require the presence of NO and are modulated by ovarian signals. 相似文献
The cover image, by Rosario Sánchez‐Gómez et al., is based on the Research Article The Microvine, a plant model to study the effect of vine‐shoot extract on the accumulation of glycosylated aroma precursors in grapes, DOI: 10.1002/jsfa.8802 .
High performance liquid chromatography was carried out to determine the soluble sugar content in canned soft drinks and commercial fruit juices stored in different types of containers. The total amount of sugars ranged from 9.2 to 13.5 g 100 ml?1 for the soft drinks, 10 to 14 g 100 ml?1 in fruit nectars and 3 g 100 ml?1 in tomato juice. The individual sugar content of soft drinks varied between different batches, although the total amount remained fairly constant for each kind of drink or juice. Only in tomato juice where sucrose was not present, did the values for glucose and fructose remain constant. 相似文献
Carotenoids were encapsulated by means of coacervation by using a nanostructured material (NE) prepared with alginate/zeolite valfor 100 (1:3) and another that was non-nanostructured (AA) prepared with alginate at 2 %. The diameter of the AA and NE capsules was ≈1,200 μm. The NE protected the carotenoids at higher water activities (aw) than the AA. The highest retention of carotenoids (7,200 mg/kg dry solids for NE and 2,230 mg/kg dry solids for AA) was observed at water activities corresponding to the minimal integral entropy (≈0.35–0.45 for NE and ≈0.1 for AA). According to the enthalpy–entropy compensation, the water adsorption in the AA capsules was enthalpy driven at aw range of 0.115–0.973. However, the NE showed two zones: (1) at low aw (0.115–0.4), the water adsorption was controlled by entropy and (2) over an aw range of 0.4–0.973, controlled by enthalpy. Atomic force microscope images, moisture content corresponding to micropore volume and thermodynamic properties suggest that the adsorption process and the carotenoids stability were controlled by entropic barriers when the water molecules were adsorbed in the micropores (nanopores with pore diameter <2 nm). The practical use of these results is that increasing the number of micropores in the solid matrix of wall materials is possible to improve the preservation of nutrients and functional substances during processing and storage of foods. 相似文献
Graphene nanosheets are a promising scaffold to accommodate S for achieving high performance Li/S battery. Nanosheet activation is used as a viable strategy to induce a micropore system and further improve the battery performance. Accordingly, chemical activation methods dominate despite the need of multiple stages, which slow down the process in addition to making them tiresome. Here, a three-dimensional (3D) N-doped graphene specimen was physically activated with CO2, a clean and single step process, and used for the preparation of a sulfur composite (A-3DNG/S). The A-3DNG/S composite exhibited outstanding electrochemical properties such as an excellent rate capability (1,000 mAh·g−1 at 2C), high reversible capacity and cycling stability (average capacity ~ 800 mAh·g−1 at 1C after 200 cycles), values which exceed those measured in chemically activated graphene. Therefore, these results support the use of physical activation as a simple and efficient alternative to improve the performance of carbons as an S host for high-performance Li-S batteries.