Alterations of beta-adrenoceptor-density and cAMP-synthesis in rat-erythrocytes after stress erythropoiesis.

During the maturation of red blood cells from rats after stress erythropoiesis, adenyl cyclase activity and beta-adrenoceptor density (pmoles/mg protein) decrease at distinctly different rates suggesting a different turnover of these membrane units.     

Cytotoxicity of ethyl methanesulfonate in mice spermatogonia.

Enumeration of different types of spermatogonia, following a single i.p. administration of different doses of ethyl methanesulfonate in mice, showed a survival of A1-A4 and in spermatogonia is markedly reduced due to cell killing while the remaining types of spermatogonia were affected marginally. The cell killing effect was dose-dependent, and replenishment of these cells was observed by the end of one cycle of the seminiferous epithelium comprising of 8.5 days.     

Increase in Na+, K+ -ATPase enzyme units in liver and kidneys from essential fatty acid deficient rats.

(3H)-Ouabain binding to liver and kidney preparations was utilized to estimate the number of Na+, K+-ATPase enzyme units in livers and kidneys from rats fed 2% corn oil supplemented or fat-free diets. The specific (3H)-ouabain binding in liver and kidney preparations from fatty acid deficient rats was increased approximately 40%, but the affinity of the binding sites for ouabain (Kd-value) remained unchanged. The increased concentration of Na+, K+-ATPase enzyme units observed in the essential fatty acid deficient rats may contribute to the reduced body fat accumulation and elevated heat production observed in these animals.     

Alkaline phosphatase in human lymphocyte subpopulations.

The levels of membrane alkaline phosphatase have been measured on different lymphocyte fractions from human peripheral blood separated on bovine serum albumin discontinuous gradients. The peak in enzyme activity was observed in a non-T-, non-B-cell fraction, rich in "null" lymphocytes; the lowest values were found in the fraction with the highest proportion of T-cells.     

Sex-dependence in triglyceride metabolism in response to dietary carbohydrates.

In humans, as well as in mice, fed on high carbohydrate diets, there was a significant sex difference in the plasma tirglycerides in that males had higher levels than females. This was mainly due to the difference in their removal rate of circulating triglycerides in the animals of both sexes. In mice, males had higher levels of liver triglycerides as well as higher rate of incorporation of U- 14C-glucose into liver triglycerides when compared to females.     

Penetration of oximes across the blood-brain barrier. A histochemical study of the cerebral cholinesterases reactivation.

The comparison of the effects of 4 oximes upon the cerebral cholinesterases reactivation after intoxication with paraoxon shows that the best results are obtained with toxogonine and 1574 [(carbaldoxime-4 pyridinium)-1(methyl-1 imidazolium-3)-3 propane]. The reactivation power of this latter compound seems due to the ease with which it can pass through the blood-brain barrier.     

Uptake of exogenous protein by supraependymal cells of the feline area postrema.

Supraependymal cells occurring on the surface of the feline area postrema were examined for phagocytic ability. It was shown that they could ingest exogenous horseradish peroxidase that was experimentally introduced into the brain ventricular system. The cells thus bear functional as well as ultrastructural attributes of macrophages, similar to those found in the third ventricle and subarachnoid space.     

Follicles development in the foetal human ovary.

In the foetal human ovary, diameters of oocyte and follicle, as well as those of oocyte and nucleus, are found to be positively and linearly correlated with each other. Follicle diameter and number of granulosa cells also show a positive and linear relationship. Finally, in all ovaries examined, from 5 months after conception onwards, small antral follicles were assessed.     

Inversal relationship between basal adenylcyclase activity and maximal degree of stimulation in membranes of red blood cells from rats.

The degree of stimulation of adenylcyclase activity, in membranes from immature red blood cells from rats, brought about by isoprenaline, guanylyl-imidodiphosphate and sodium fluoride is strongly dependent on the basal activity of the enzyme. The inversal relationship between basal activity and the maximal degree of stimulation by (--) isoprenaline, shows an apparent seasonal dependence.     

Radioimmunoassay of plasma progesterone, testosterone, total estrogen and immunoreactive gonadotropin in the nesting and non-nesting green sea turtle, Chelonia mydas (L.).

Plasma progesterone, testosterone, total estrogens and immunoreactive gonadotropin were measured in nesting and non-nesting sea turtles, Chelonia mydas. Progesterone and gonadotropin concentrations were significantly higher in nesting than in non-nesting turtles, testosterone was not significantly different in either group and total estrogens appeared to be slightly in the nesting group.