Acta physiologica latino americana最新文献

The acute effects of 4 different brands of the most popular Brazilian alcoholic beverage, the so called "cachaças" (distilled product of sugar cane), were measured through the loss of the righting reflex and the rotarod test. The effects induced by the cachaças were greater than it could be predicted through the ethanol content alone.

The effect of posterior lobe extracts on prolactin secretion in vitro was compared with that of median eminence, hypothalamic (with and without median eminence) and cortex extracts. The posterior lobe extract clearly inhibited adenohypophysial prolactin secretion, showing a similar effect to that of the hypothalamic extracts. The median eminence extract showed inconstant inhibitory effects, while the cerebral cortex extracts showed no effect. The removal of the median eminence did not modify the hypothalamic inhibitory effect. Although the median eminence has always been considered to be the final common pathway for the control of adenohypophysial secretion, these results suggest that the posterior lobe may also play a physiological role in this control.

The effects of trypsin, phospholipase A, and chymotrypsin on NADPH-cytochrome c reductase and cytochrome P-450 of microsomes from cryptorchid mouse testes and liver were compared. Trypsin released both enzymes almost completely from testis microsomes, while it readily released only NADPH-cytochrome c reductase from liver microsomes. Chymotrypsin alone, even under conditions where 30-40% of the microsomal protein was hydrolyzed, had little effect on localization or activity of either enzyme in either tissue. Phospholipase A destroyed cytochrome P-450 in testicular microsomes but had little effect on this enzyme in hepatic microsomes or on NADPH-cytochrome c reductase in either preparation. When, however, the microsomes were incubated with chymotrypsin in the presence of a detergent, the effects were similar to those of trypsin alone; testicular cytochrome P-450 was destroyed, while hepatic cytochrome P-450 was only slightly solubilized, and NADPH-cytochrome c reductase from both types of microsomes was both solubilized and activated. From these results we conclude that arginyl and/or lysyl bonds may play a significant role in the junction between the hydrophobic region of the membrane and the anchor region of the reductase molecule and that cytochrome P-450 of testicular microsomes is more superficially located in the lipid bilayer than is hepatic microsomal cytochrome P-450.

The method of curve fitting here described is simple, dependable and can be programmed in a hand calculator. It consists in a log linear regression "peeling" that uses the maximization of the correlation coefficient for determining the number of exponential terms. It was experimentally verified and found to give satisfactory answers when compared to weighted least square iterative techniques.

Serial sections of haemopoietic liver from 12 to 17 days old mice embryos were studied. The percentual values of cycling erythroid cells, located at vascular level, show a continuous decay through the entire hepatic phase of erythropoiesis. Since the 15th day onwards no differences were found in the cellular blood composition between the general circulation and the vascular channels of the central area of the growing lobes. Nevertheless, other more peripheric areas of the liver have a slowed decrease of circulating young cells, when compared with the former. On the contrary, in the marginal zones, interstitial proerythroblasts increase their percentual values towards the 13th day, coinciding with the moment on which they predominate all over other more mature demes. This increment is not explainable by self renewal only, since their mitotic indexes undergo a decay, which is unexpected in a growing population. Interstitial non erythroid cells seem not to play a role in the increment of proerythroblasts in the proliferating areas.

Intestinal Ca and P absorption was investigated on rachitic chicks raised on diets with a 1% Ca and 0.3% or 1% P contents. 45Ca and 32P absorption was determined by the technique of the isolated gut sac in vivo. In addition, 32P transport was also measured by the everted gut sac procedure in vitro. Treatment with vit. D3 during 7 days increased the 45Ca absorption in animals fed diets containing 0.3% or 1% P. 32P absorption showed an increase after 2 days of treatment and a decrease afterwards. The reduction of 32P absorption was larger in animals fed diet with 1% P. Study of 32P transport with the everted gut sac technique showed an increase after vit. D3 and a loss of intracellular P, regardless the duration of treatment.

A sensitive and reliable fluorometric method for the simultaneous determination of dopamine, noradrenaline, 5-hydroxytryptamine and 5-hydroxy-indol acetic acid in small samples of brain tissues is described. The procedure is based on solvent extraction; catecholamines are oxidized by the Chang's method and 5-hydroxytryptamine and 5-hydroxy-indol acetic acid determined by reaction with o-phthalaldehyde, alpha-methyl-p-tyrosine causes a negligible interference with the procedure. Results of determination of these amines in different brain areas are reported.

A study was made of the control of the hypothalamus and neuroendocrine complex by the specialized receptors: the eye, the ear and the olfactory complex. The ancient and modern evidence that light, acting on the optic system, can influence hypothalamic, hypophyseal, endocrine reactions was reviewed and the recently acquired evidence that an optic-hypothalamic-autonomic-pineal-hypothalamic circuit exists which controls liberation of "releasing hormones". Evidence was presented to show that the ear and eye, extero-and interoceptive influences affect lactation and oxytocin secretion by action through the hypothalamus. It was also shown that electrochemical stimulation of the olfactory bulbs can affect both sexual behavior and gonadotropin secretion. Finally, it was shown that the olfactory system exerts some control over water intake, sodium appetite and antidiuretic hormone secretion. Progress in a long term cooperative study of the role of exteroceptor control of neuroendocrine functions was reported.