The effects of testosterone manipulation on the body condition of captive male yellow-legged gulls.

Persistently high testosterone levels are believed to be costly to males due to their negative effect on body condition. However, this assumption could not be validated when we analysed birds isolated from all social interactions. The hypothesis was tested on birds kept in isolation in order to analyse the effects of testosterone per se, and thereby exclude the influence of social interactions.

Food deprivation and refeeding in Atlantic salmon,Salmo salar: effects on brain and liver carbohydrate and ketone bodies metabolism.

The capacity of carbohydrate and ketone bodies metabolism in brain and liver was evaluated in fed and food-deprived Atlantic salmon (Salmo salar) in a time period covering from 1 to 7 days (Experiment I), and in Atlantic salmon food deprived for 6 weeks, and food deprived for 4 weeks and refed for 2 weeks (Experiment II). The results obtained demonstrate for the first time in a teleost the existence of changes in brain metabolism due to food deprivation. Thus, decreased glucose levels in plasma are reflected in the brain by an increased mobilization of glycogen reserves, and by a decreased glycolytic capacity.

Effects of acute ethanol administration on regional serotonin turnover.

Numerous studies show the role of biogenic amines in the effects of ethanol. The present work analyzed the effect of an acute sedative-hypnotic dose of ethanol (4 g/kg) on the levels of tryptophan, serotonin (5-HT) and 5-hydroxyindol-acetic acid (5-HIAA), the serotonin synthesis rate and the 5-HIAA elimination rate in several regions of the brain. The 5-HT synthesis rate was not enhanced by ethanol administration, despite increases in brain tryptophan, 5-HT and 5-HIAA, which were primarily in the medulla-pons.

Ontogeny of the novel tachykinins neurokinin A, neurokinin B and neuropeptide K in the rat central nervous system.

Neurokinin A, neurokinin B and neuropeptide K content has been measured in several regions of the rat central nervous system at different stages of postnatal development. For this, we have employed a combination of HPLC separation and radioimmunoassay detection using a neurokinin A antiserum which also recognizes neurokinin B and neuropeptide K. All 3 tachykinins were detectable during postnatal development in the various regions studied (hypothalamus, striatum, substantia nigra, cerebral cortex and spinal cord).

Rat blood and brain amino acid pattern in short term experimental diabetes.

Some serum and brain amino acid variations occurring in animals with short term streptozotocin-diabetes (24 h) are studied in this work. Diabetic animals showed an increase in serum of the three branched-chain amino acids as well as an increase in free tryptophan, besides a decrease in total serum tryptophan and in the tryptophan/competitor amino acids ratio. In brain, the three branched-chain amino acids increased, but there were no variation in whole brain tryptophan.

Effects of short term experimental diabetes on brain serotonin metabolism.

Serotonin metabolism was studied in several brain regions of control and Streptozotocin-treated male Wistar rats. After induction of diabetes, the animals were killed at 24 hours. Concentrations of brain tryptophan show a generalized increase in all brain regions, being only significant in medulla-pons.

Effect of low doses of gamma-hydroxybutyric acid on serotonin, noradrenaline, and dopamine concentrations in rat brain areas.

The effects of intraperitoneal administration of gamma-hydroxybutyric acid (GHB) on biogenic amine levels in hemispheres, hypothalamus, midbrain, and medulla-pons, and on tryptophan in serum and brain, were studied. One hour after GHB administration (50 and 100 mg/kg) significant increases of dopamine concentration were observed in the hemispheres with both doses and in the hypothalamus with the higher dose, but a significant decrease of noradrenaline in the hypothalamus. No significant changes of serotonin metabolism were observed.