Sex steroid changes in porcine cystic ovarian disease

Ten sex steroids were measured in the peripheral serum and ovarian follicular fluid of female pigs with or without cystic ovarian disease. In general, progestin, especially progesterone, accumulated excessively in the fluid contained in cystic compared with normal follicles. Nonluteinized cystic follicles contained up to four times the progesterone concentration found in large normal preovulatory follicles. Levels of this steroid increased with luteinization of cystic follicles to as much as 10 times those found in large preovulatory follicles. In contrast, the concentration of follicular fluid androgens and estrogens in cystic follicles were, at best, barely detectable (5 to 10 pg/ml). These results are indicative of a steroidogenic blockade in the conversion of C21 progestin to C19 androgens and C18 estrogens in the cystic follicles. In spite of an enormous accumulation of follicular progestin and subnormal concentration of androgens and estrogens, circulating levels of these hormones in pigs bearing cystic ovaries were in the normal range for cycling sows. Clearly, the hormonal abnormalities in the cystic follicles are not reflected in the serum profiles of these steroids.     

Isolation of soluble elastin from lathyritic chicks. Comparison to tropoelastin from copper deficient pigs.

Tropoelastin was isolated from the aortas of chicks rendered lathyritic by treatment with beta-aminopropionitrile. The soluble elastin was judged homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis and possessed an estimated molecular weight of 70000. Automated sequential analysis revealed that the N-terminal region of the chick tropoelastin is very homologous to tropoelastin isolated from copper-deficient piglets. N-terminal analysis of a trypsin digest of chick tropoelastin showed that tyrosine frequently is found adjacent to lysine residues. This positioning of tyrosine residues may be significant in terms of a possible regulatory role in elastin cross-link formation.     

DNA replication and the development of spontaneous mutations in the somatic cells of mammals. I. The relationship between the outcome of gene mutations and the duration of cell life]

The reduction of serum concentration in culture medium to 0,1% was proposed as a method of slowing division and DNA replication in Chinese hamster cells in vitro. Under these conditions the rate of DNA replication was reduced by more than one order of magnitude, while cell viability remained high enough (about 10%) for a long period up to 30 days. The spontaneous mutation rate to 6-mercaptopurine resistance, as calculated per day in cells with reduced DNA replication rate, was comparable to that in normally dividing cells [(1,2 +/- 0,3) X 10(-5) and (3,1 +/- 0,5) X 10(-5) per cell per day respectively]. This proves that a considerable fraction of spontaneous mutants arise independently on DNA replicative synthesis.     

Triacylglycerol biosynthesis in the adipose tissue of the obese-hyperglycaemic mouse.

Obesity in obese-hyperglycaemic mouse is associated with an increase in number and size of adipocytes. Adipocytes from the obese mouse showed increased incorporation of [14C]acetate and[14C]glucose into triacylglycerol. This increased capacity of triacylglycerol formation was correlated with increased activities of various triacylglycerol-forming enzymes measured in the microsomal fraction of adipose tissue from obese mice. Microsomal fractions from lean and obese mice contained sn-glycerol 3-phosphate acyltransferase, phosphatidate phosphohydrolase and diacylglycerol acyltransferase. Phosphatidate phosphohydrolase was also detected in the soluble fraction. In the presence of Mg2+, the phosphatidate phsophohydrolase from the soluble and the microsomal fractions was active towards membrane-bound phosphatidate. Among the three enzymes studied here, the increase in Mg2+-dependent phosphatidate phosphohydrolase was most prominent in adipose tissue of obese mice.     

Apparent sulfation of glycosaminoglycans by ascorbic acid 2-[S]Sulfate: An explanation

The sulfation of glycosaminoglycans by ascorbic acid 2-[^{3 5}S]sulfate was studied in costal cartilage and chrndrocytes in vitro. Negligable (if any) sulfation of glycosaminoglycans was detected with immediately isolated ascorbic acid 2-[^{3 5}S]sulfate. However, formation of [^{3 5}S]glycosaminoglycans was readily detected with ascorbic acid 2-[^{3 5}S]sulfate which had been stored at −20°C for several days. The [^{3 5}S]glycosaminoglycans did not result from the direct transfer of ^{3 5}S from ascorbic acid 2-sulfate but rather from a decomposition product of ascorbic acid 2-[^{3 5}S]sulfate.Evidence is presented to show that the sulfation pathway with the decomposition product involves exchange with inorganic sulfate, and strongly suggests that sulfation proceeds via 3′-phosphoadenosine 5′-phosphosulfate. The decomposition product appears similar to inorganic sulfate in several test systems. In view of these observations, it is suggested that previous conclusions implicating ascorbic acid 2-sulfate as a biological sulfate donor, based on the use of ascorbic acid 2-[^{3 5}S]sulfate be re-evaluated.