The obese Göttingen minipig as a model of the metabolic syndrome: dietary effects on obesity, insulin sensitivity, and growth hormone profile

The objective of the study reported here was to induce obesity in the female G?ttingen minipig to establish a model of the human metabolic syndrome. Nine- to ten-month-old female G?ttingen minipigs received a high-fat high-energy (HFE) diet or a low-fat, low-energy (LFE) diet. The energy contents derived from fat were 55 and 13 %, respectively. After 5 weeks, animals were subjected to dual energy x-ray absorptiometry (DEXA) scanning, intravenous glucose tolerance testing (IVGTT), and 6-h growth hormone profile recording. After treatment, mean body weight of pigs of the LFE group was 21.0 +/- 0.4 kg, and was 26.8 +/- 0.2 kg in pigs of the HFE group (P < 0.0001). The DEXA scanning indicated that the fat content of the LFE group was 10.0 +/- 1.2 % versus 15.2 +/- 0.7 % in the HFE group (P < 0.003). Triglycerides concentration was significantly (P < 0.05) increased in pigs of the HFE group (0.24 +/- 0.03 mM), compared with that in pigs of the LFE group (0.13 +/- 0.04 mM). Preprandial plasma glucose and insulin concentrations were not affected, but insulin area under the curve during IVGTT was significantly high in the obese animals. Growth hormone (GH) secretion was low in both groups of pigs. The obese minipig shares some of the metabolic impairments seen in obese humans, and may thus serve as a model of the metabolic syndrome.     

Stomatal responses to carbon dioxide of isolated epidermis from a C3 plant,the Argenteum mutant of Pisum sativum L., and a crassulacean-acid-metabolism plant Kalanchoë daigremontiana Hamet et Perr

The response of stomata in isolated epidermis to the concentration of CO₂ in the gaseous phase was examined in a C₃ species, the Argenteum mutant of Pisum sativum, and a crassulacean-acid-metabolism (CAM) species, Kalanchoë daigremontiana. Epidermis from leaves of both species was incubated on buffer solutions in the presence of air containing various volume fractions of CO₂ (0 to 10000·10^–6). In both species and in the light and in darkness, the effect of CO₂ was to inhibit stomatal opening, the maximum inhibition of opening occurring in the range 0 to 360·10^–6. The inhibition of opening per unit change in concentration was greatest between volume fractions of 0 and 240·10^–6. There was little further closure above the volume fraction of 360·10^–6, i.e. approximately ambient concentration of CO₂. Thus, although leaves of CAM species may experience much higher internal concentrations of CO₂ in the light than those of C₃ plants, this does not affect the sensitivity of their stomata to CO₂ concentration or the range over which they respond. Stomatal responses to CO₂ were similar in both the light and the dark, indicating that effects of CO₂ on stomata occur via mechanisms which are independent of light. The responses of stomata to CO₂ in the gaseous phase took place without the treatments changing the pH of the buffered solutions. Thus it is unlikely that CO₂ elicited stomatal movement by changing either the pH or the HCO ₃ ^– /CO ₃ ^2- equilibria. It is suggested that the concentration of dissolved unhydrated CO₂ may be the effector of stomatal movement and that its activity is related to its reactivity with amines.     

Do the maximum sizes,ages and patterns of growth of three reef‐dwelling labrid species at two latitudes differ in a manner conforming to the metabolic theory of ecology?

The size and age data and patterns of growth of three abundant, reef‐dwelling and protogynous labrid species (Coris auricularis, Notolabrus parilus and Ophthalmolepis lineolata) in waters off Perth at c. 32° S and in the warmer waters of the Jurien Bay Marine Park (JBMP) at c. 30° S on the lower west coast of Australia are compared. Using data for the top 10% of values and a randomization procedure, the maximum total length (L_T) and mass of each species and the maximum age of the first two species were estimated to be significantly greater off Perth than in the JBMP (all P < 0·001) and the maximum ages of O. lineolata in the two localities did not differ significantly (P > 0·05). These latitudinal trends, thus, typically conform to those frequently exhibited by fish species and the predictions of the metabolic theory of ecology (MTE). While, in terms of mass, the instantaneous growth rates of each species were similar at both latitudes during early life, they were greater at the higher latitude throughout the remainder and thus much of life, which is broadly consistent with the MTE. When expressed in terms of L_T, however, instantaneous growth rates did not exhibit consistent latitudinal trends across all three species. The above trends with mass, together with those for reproductive variables, demonstrate that a greater amount of energy is directed into somatic growth and gonadal development by each of these species at the higher latitude. The consistency of the direction of the latitudinal trends for maximum body size and age and pattern of growth across all three species implies that each species is responding in a similar manner to differences between the environmental characteristics, such as temperature, at those two latitudes. The individual maximum L_T, mass and age and pattern of growth of O. lineolata at a higher and thus cooler latitude on the eastern Australian coast are consistent with the latitudinal trends exhibited by those characteristics for this species in the two western Australian localities. The implications of using mass rather than length as the indicator variable when comparing the maximum sizes of the three species and the trends exhibited by the instantaneous growth rates of those species at different latitudes are explored. Although growth curves fitted to both the L_T and masses at age for the males of each species lay above those for their females, this would not have influenced the conclusions drawn from common curves for both sexes.     

Diacylglycerol kinase α mediates 17-β-estradiol-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line through the G protein-coupled estrogen receptor GPR30

Increased levels of endogenous and/or exogenous estrogens are one of the well known risk factors of endometrial cancer. Diacylglycerol kinases (DGKs) are a family of enzymes which phosphorylate diacylglycerol (DAG) to produce phosphatidic acid (PA), thus turning off and on DAG-mediated and PA-mediated signaling pathways, respectively. DGK α activity is stimulated by growth factors and oncogenes and is required for chemotactic, proliferative, and angiogenic signaling in vitro. Herein, using either specific siRNAs or the pharmacological inhibitor R59949, we demonstrate that DGK α activity is required for 17-β-estradiol (E2)-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line. Impairment of DGK α activity also influences basal cell proliferation and growth in soft agar of Hec-1A, while it has no effects on basal cell motility. Moreover, we show that DGK α activity induced by E2, as well as its observed effects, are mediated by the G protein-coupled estrogen receptor GPR30 (GPER). These findings suggest that DGK α may be a potential target in endometrial cancer therapy.