Spermine synthesis in the uterus of the ovariectomized rat in response to oestradiol-17

Purification and properties of oestrogen-induced uterine peroxidase

1. An enzyme that can be induced in rat uteri by oestrogens and that catalyses the oxidation of guaiacol and the metabolism and binding of [4-14C]oestradiol to protein in the presence of H2O2 was partially purified by (NH4)2SO4 fractionation and polyacrylamide-gel chromatography. 2. The molecular weight of this uterine peroxidase was estimated to be about 40 000 and thus shown to differ from that of eosinophil peroxidase. 3. Cycloheximide, which blocks the increase in peroxidase activity brought about by oestrogen, was used to determine the half-life (about 4h) of the induced uterine enzyme.

Polyamine alterations in blood of male homozygotes and heterozygotes for cystic fibrosis

The polyamines, spermidine and spermine, have been measured in whole blood extracts from control volunteers, patients with cystic fibrosis, and obligate cystic fibrosis heterozygotes. Male homo- and heterozygotes for cystic fibrosis exhibit a consistent and significant decrease in blood spermine resulting in an elevated spermidine/spermine ratio when compared to control males. In contrast, control females exhibited reduced spermidine and spermine levels as compared to control males. Blood from female cystic fibrosis homo- and heterozygotes showed similar results. The sex difference is probably due to fluctiations of blood polyamines during the menstrual cycle. Abnormal polyamine levels are the first observation of an alteration of a low molecular weight metabolite characteristic of both male homo- and heterozygotes for cystic fibrosis.

Alterations in the accumulation patterns of polyamines in brains of myelin-deficient mice

Quaking mutants and jimpy mutants of mice have known deficiencies of myelination of the central nervous system, as well as lesser involvement of the peripheral nervous system. Both mutants also have altered polyamine synthesis and accumulation, particularly in the hindbrain and spinal column. The ratio of spermidine/spermine, which generally is higher in tissues with high rates of biosynthetic activity, was significantly lower in the mutants as compared to their normal siblings. In quaking mutants, 5 months of age, the spermidine concentration of hindbrain and spinal column was 60% that of controls. In contrast, the decreased spermidine/spermine ratio in jimpy mutants resulted from a marked increase in the spermine concentration in both forebrain and hindbrain. Alterations in the spermidine/spermine ratio could lead to reductions in the biosynthetic potential of the brain during development.

Cell cycle specific fluctuations in adenosine 3':5'-cyclic monophosphate and polyamines of Chinese hamster cells

Chinese hamster V79 cells were synchronized by mitotic selection, which resulted in approximately 95% synchrony. The adenosine 3':5'-cyclic monophosphate level was elevated within 3 hr (G1 phase) and reached a level 2-fold higher than in early G1 within 6 hr (early S phase). An increase in ornithine decarboxylase activity (6-ornithine carboxy-lyase, EC 4.1.1.17), the initial enzyme in the polyamine biosynthetic pathway, was detected within 4 hr and was maximal at 8 hr. Since about 20% of the cells were labeled with [3-H]thymidine at 4 hr, ornithine decarboxylase exhibits cell-cycle specific activity starting in late G1 and continuing through middle S phase. The activity of S-adenosylmethionine decarboxylase (S-adenosyl-L-methionine carboxylase, EC 4.1.1.50) increased within 5 hr, i.e., early S phase. It is suggested on the basis of these data and other studies discussed herein that the increase in ornithine decarboxylase activity, which parallels closely the elevation in cyclic AMP, is an example of adenosine 3':5'-cyclic monophosphate-mediated protein synthesis.

Spermidine in hormone-dependent differentiation of mammary gland in vitro

Stiulation of milk-protein synthesis in mouse mammary epithelium in vitro requires insulin, hydrocortisone, and prolactin. The requirement for hydrocortisone can be replaced by spermidine. The possibility that spermidine mediates the effect of glucocorticoid is also supported by the observation that the cellular spermidine concentration increases before the accelerated synthesis of casein and alpha-lactalbumin.