Organization and dynamics of lipids in bovine brain coated and uncoated vesicles

Three characteristics have been demonstrated by the chemical analysis of bovine brain coated vesicles following removal of the coat proteins: a high protein content, a high cholesterol/lipid ratio and a high percentage of phosphatidylethanolamine amongst the phospholipids.The study of lipid bilayer organization and dynamics has been performed using the fluorescent probes pyrene and parinaric acid (cis and trans). This has allowed the study of both lateral mobility and rotational motion in the lipid bilayer of the coated and uncoated vesicles.Lateral mobility in the fluid phase of the lipid is slightly reduced by the presence of the clathrin coat, as indicated by the lower diffusion coefficient of pyrene in coated compared with uncoated vesicles.At all temperatures from 6° to 30°C, solid-phase domains, probed by trans parinaric acid, coexist with fluid-phase domains in the lipid bilayer. The temperature dependence of the parinaric acid lifetimes and of their amplitudes strongly suggests that the solid phase domains decrease in size with temperature, both in coated and uncoated vesicles.However, the difference in the value of the anisotropy at long times (r ), between coated and uncoated vesicles (a difference which is more pronounced for cis than for trans parinaric acid), indicates that the presence of the clathrin coat introduces disorder in the surrounding lipids, thus suggesting a possible role of the clathrin in the formation of the pits on the plasma membrane.Abbreviations CVs coated vesicles - UVs uncoated vesicles - TLC thin layer chromatography - DMSO dimethylsulfoxide - DPPC dipalmitoylphosphatidylcholine - cis Pna cis parinaric acid - (9,11,13,15-cis-trans-trans-cis) octadecatetraenoic acid - Trans Pna Trans parinaric acid - (9,11,13,15-all-trans) octadecatetraenoic acid     

Response of the epididymis, ductus deferens & accessory glands of the castrated prepubertal rhesus monkey to exogenous administration of testosterone or 5alpha-dihydrotestosterone.

The response of the epididymis, ductus deferens, and accessory glands of the castrated prepubertal rhesus monkey to exogenous administration of testosterone or 5alpha-dihydrotestosterone (DHT) was investigated. 200 or 800 mcg of either steroid/day were administered for 60 days beginning on the day after castration. Castration caused a marked regression of the weight of and secretory function of the reproductive organs; testosterone/DHT stimulated their growth and secretory activity which were maintained at the level of the controls. The weight of the caput epididymides however, was unaffected by testosterone but was stimulated by DHT. DHT caused a greater stimulation of the growth and secretory activity of the reproductive organs than testosterone and also caused a hyperstimulation of secretion by the seminal vesicles. The data, analyzed statistically, show that the accessory organs of the prepubertal rhesus monkey are affected by castration and vary in their response to stimulation by exogenous androgens.     

Regional differences in the metabolism of testosterone in vitro in the epididymis & ductus deferens of the adult rhesus monkey Macaca mulatta.

Regional differences in the metabolism of testosterone in vitro in the epididymis (1.5 cm segments) and ductus deferens (2 cm segments) were investigated in the adult rhesus monkey, Macaca mulatta. The conversion of tritiated testosterone to its 5alpha-reduced derivatives increased from the proximal to the distal regions of the epididymis. The total amount of 5alpha-reduced products in the subsequent segments of the epididymis was highest in the intact monkey and on the intact side of the unilaterally castrated monkey and was followed in decreasing order by the castrated side of the hemiscastrate and least in the bilateral castrate. Hormonal requirements for maintenance of the biological functions of the epididymis and maturation of spermatozoa in the epididymis are discussed.     

Effects of a highly purified antiserum to FSH on testicular function in immature rats

Effects of highly purified antiserum (AS) to follicle stimulating hormone (FSH) on testicular function was studied in immature rats. Treatment with FSHAS for 10 days, from 25-34, decreased weights of the testis (p .001) and increased weights of the epididymis (p .05). Numbers of the cell types in the seminiferous epithelium, particularly Type A spermatogonia pachytene spermatocytes and spermatids, were markedly reduced, possibly due to: 1) decreased division of the initial stem cells, 2) impairment of division of Type B spermatogonia and their transformation to pachytene spermatocytes, and 3) desquamation and degeneration of pachytene spermatocytes and spermatids. FSHAS also affected the sertoli cell function which was reflected in the decreased binding of androgens to supernatant fraction of the testis and epididymides. Treatment with luteinizing hormone-AS for 5 days did not affect testicular function but the binding of androgens to the supernatants of the caput and cauda epididymides and ventral prostate was significantly reduced (p .001). These data indicate that FSH is necessary for the maintenance of the cellular integrity of the seminiferous epithelium during the completion of the 1st wave of spermatogenesis.     

Pentobarbital sodium inhibits calcium uptake in vascular smooth muscle

This report demonstrates that the commonly used anesthetic agent, pentobarbital sodium, in concentrations of 1 · 10^?4 to 2 · 10^?3 M inhibits calcium (Ca²⁺) uptake in both rat aortic and portal venous smooth muscle. The data indicate that total exchangeable Ca²⁺ in portal vein is reduced by about 15% in 1 · 10^?4 M pentobarbital sodium, while the intracellular exchangeable Ca²⁺ is reduced by 24%. On the other hand, in aortic smooth muscle, while 5–20 · 10^?4 M pentobarbital sodium reduces total exchangeable Ca²⁺ by about 15%, intracellular Ca²⁺ is reduced by 22% in 5 · 10^?4 M pentobarbital sodium and by 38% in 2 · 10^?3 M pentobarbital sodium. The present studies thus reveal that concentrations of pentobarbital sodium known to be present during induction of surgical anesthesia can exert significant inhibitory effects on exchangeability and transmembrane movement of Ca²⁺ in at least two different types of blood vessels.     

EFFECTS OF DIETARY PROTEINS ON FETAL BRAIN PROTEIN AND GLUTAMIC ACID METABOLISM IN RAT

Abstract— The effects of feeding dietary wheat and Bengal gram proteins to pregnant rats on brain protein and glutamic acid metabolism in 15-, 17- and 19-day fetuses were investigated. Wheat and Bengal gram diets resulted in loss of brain weight with decreased DNA, RNA, protein, free x amino N and deficits in the activities of brain glutamine synthetase, glutaminase I. glutaminase II and glutamate decarboxylase at all the gestational ages studied without any change in glutamine transferase activity. The concentrations of the amino acids alanine, glutamic acid, glutamine and GABA were found to be significantly lower on wheat and Bengal gram diets than the control on a 10% casein diet. The wheat with lysine and Bengal gram with methionine, cystine and tryptophan resulted in similar mean values of all the characteristics studied to the mean values observed in rats on the control diet. However, glutaminase I activity remained significantly low on lysine fortified wheat diet, and aspartic acid content was found to increase on both fortified and unfortified wheat and Bengal gram diets. A 20% casein diet showed increased brain weight, DNA. RNA. protein and free x amino N concentrations as compared with the 10% casein diet, while the other parameters remained unchanged.