Effects of bisphenol-A on the growth of comb and testes of male chicken

Bisphenol-A (BPA) has been reported to have some xenoestrogenic effects on the reproductive system of male animals. In this study, we examined the growth of combs and testes of the male chickens exposed to BPA. White leghorn male chicks were administered 200 mg BPA orally every week from 2 wk of age. The combs and testes were examined at 16 wk of age. The body growth showed no significant difference between BPA-administered and control birds. However, the weight of the combs and testes were lower in the BPA-treated birds. Histologically, testes of the control birds were well matured; the seminiferous tubuli were filled with sperm. In contrast, the testes of most of the BPA-treated birds showed an immature appearance with smaller seminiferous tubuli and limited spermatogenesis. These findings suggest that the xenoestrogenic property of BPA might disturb the growth of the comb and testes of male chickens by a possible endocrine disrupting mechanism.     

Study of the role of the carbohydrate and protein moieties of soy soluble polysaccharides in their emulsifying properties

The objective of this work was to investigate the role played by the protein fraction of soy soluble polysaccharide (SSPS) during its adsorption at oil/water interfaces. SSPS was separated in a high (HMF; 310 kDa) and low (LMF; 20 kDa) molecular weight fraction by gel filtration. SSPS/HMF consisted of 91.6% carbohydrate and 2.2% protein and showed better emulsifying properties than those of the whole SSPS, whereas SSPS/LMF seemed to affect negatively the adsorption behavior of SSPS. SDS-PAGE of the protein fraction obtained from SSPS/HMF showed a molecular mass of 50 kDa, was composed predominantly of proline (23.1%) and glutamic acid (15.2%), and still contained 8.8% of neutral sugar and 5.3% of uronic acid. Results indicated that not all of the protein material present in SSPS contributes to SSPS functionality but that only the material associated with HMF aids in the adsorption of SSPS onto oil/water interfaces.     

Effect of hyperlipidemia on cardiovascular responses to adrenergic stimulation in piglets.

This study was designed to assess the effect of hyperlipidemia on cardiovascular responses to adrenergic stimulation in a porcine model. Four-week-old piglets (n = 10) were divided into two groups; one fed a control diet and the other was fed an atherogenic diet for 8 weeks. Cardiovascular responses were evaluated to both norepinephrine (NE; 0.5 and 2.5 micrograms/kg) and isoproterenol (ISO; 0.1 and 0.5 microgram/kg) from simultaneous recordings of femoral arterial pressure, heart rate, left intraventricular pressure and left intraventricular dP/dt. It was found that no significant difference in the baseline values of cardiovascular function was observed between the control and hyperlipidemic groups. However, in the hyperlipidemic group as compared with the control group: 1) arterial blood pressure responses to NE were significantly increased (P less than 0.05), 2) cardiac contractile responses to NE and ISO were significantly potentiated (P less than 0.05), and 3) reflex bradycardia in response to increasing arterial blood pressure did not occur. These findings indicate that hyperlipidemia can potentiate the cardiovascular responses to adrenergic stimulation, whereas reflex cardiovascular regulation is somewhat altered by hyperlipidemia. Conceivably, these observations may have relevance to the possible role of the mechanism of the interaction of hyperlipidemia and hypertension in atherogenesis.     

Enzyme activity changes during anthocyanin synthesis in ‘Olympia’ grape berries

Anthocyanin synthesis began in the skin of ‘Olympia’ (Vitis labruscana Bailey) grape when the berry growth reached a late stage in the second sigmoid growth-curve. During berry development, shikimate NADP oxidoreductase (SORase, EC.1.1.1.25), phenylalanine ammonia-lyase (PAL, EC.4.3.1.5), and chalcone flavanone isomerase (CHFI, EC.5.5.1.6) were investigated in the skin. These enzyme activities were high during early development of the young berry, but rapidly decreased thereafter, and were activated again when rapid anthocyanin synthesis subsequently occurred. When PAL from the young berry was analyzed by isoelectricfocusing polyacrylamide gel electrophoresis (IEF-PAGE), it showed a single activity band with a pI value of approximately 5.4, whereas PAL from the ripe berry showed two activity bands with pIs of 5.4 and 6.5. Thus, SORase, PAL, and CHFI seem to be involved in anthocyanin accumulation simultaneously, and newly synthesized isozyme of PAL may play a key role in pigment formation in ‘Olympia’ skin. The function of these enzyme activities in young berry is also discussed in this text.     

Effects of estrogen on growth hormone pulsatility in peripheral blood and neuropeptide profiles in the cerebrospinal fluid of goats

We previously reported that growth hormone (GH) pulses were negatively associated with neuropeptide Y (NPY) profiles in cerebrospinal fluid (CSF) of the third ventricle of Shiba goats. In addition, while most GH pulses were coincident with GH-releasing hormone (GHRH) pulses, there was no correlation between GH and somatostatin (SRIF) levels. The present study was performed to elucidate the relationship between GH pulses and these neuropeptide levels in CSF when estradiol (1.0 mg/head) was subcutaneously administered to ovariectomized goats. CSF and plasma samples were collected every 15 min for 18 h (from 6 h before to 12 h after injection). GH levels in peripheral blood and GHRH, SRIF and NPY levels in CSF were measured by radioimmunoassay. Pulse/trough characteristics and correlations were assessed by the ULTRA algorithm and cross-correlation analysis. Before estradiol was injected, significant coincidence was found between GHRH pulses and GH pulses, and negative coincidence was found between NPY troughs and GH pulses. Six to 12 h after estradiol injection, the amplitude and area under the curve (AUC) of the GH pulses were markedly increased. The duration and AUC of the GHRH pulses in the CSF were also increased, and stronger synchrony of GHRH with GH was observed. In contrast, the baseline of NPY was significantly decreased, and the negative correlation between the GH pulses and NPY troughs disappeared. The parameters of SRIF troughs were not clearly changed. These observations suggest that estrogen enhances the pattern of secretion of GH in the goat via enhancement of GHRH pulses and decrease of NPY levels.