[Study on the relationship between lifestyles and maximal oxygen uptake in healthy adults].

In this study, to determine the influence of different lifestyles on maximal oxygen uptake, we carried out a survey on the effects of age, smoking, physical exercise, clinical examination values and dietary habits of 899 male factory workers on their maximal oxygen uptake. The results of the study were as follows: Maximal oxygen uptake significantly decreased with age. In the male factory workers, there were significant correlations between maximal oxygen uptake and frequency of physical exercise, a greasy diet and seasoning of the diet. Multiple regression analysis showed that the variables which correlated best with the maximal oxygen uptake were serum total cholesterol and HDL cholesterol. These results indicated that good nutrition and physical activity are important for maintaining physical fitness.

[Experimental study on effects of a high-sugar diet and physical exercise on serum phospholipids in young adults].

The life style of young adults has been receiving attention with a view to its improvement to prevent coronary heart diseases (CHD) later in life. In this study, to determining the influence of different life styles on the serum phospholipids level, we carried out experimental studies on the effects a high sugar diet and physical exercise on serum phospholipid levels. Considering the trend for young people to consume large quantities of carbonated drinks, in which most of the sugar is sucrose, we tested the effect of a high carbohydrate diet on one group of six healthy male subjects and did not find that it caused a significant increase in the serum phospholipids level. In another group of 108 healthy young female subjects, a mild exercise regimen results in a slight, but significant decrease in the serum phospholipid level (p < 0.01). The serum total cholesterol level of the group did not exhibit a significant change.

Effect of diet and lifestyle on bone mass in Asian young women.

The relationship between bone mineral content (BMC) divided by bone width (BW) and diet and lifestyle in early adulthood were investigated from the view point of preventing osteoporosis at a young age in Asian women. BMC/BW of 161 healthy Asian women aged 19-25 y were measured by single-photon absorptiometry. Current and past dietary habits and physical activity were also studied. BMC/BW varied from 0.21 to 0.48 g/cm2. Bone density correlated well with dietary habit from infancy to the present especially with calcium and past physical activity. These two factors showed additive effects on BMC/BW. In multiple-regression analysis, liking sports, body mass index, no milk intake in childhood, protein intake, frequency of dieting, and skipping meals were contributors to bone density and predictive of 23% of the variability in BMC/BW in the total group. The multiple-regression coefficient was 0.518. Smoking, drinking, and duration of sunbathing might have no effect on BMC/BW in early adulthood.

Organization and structure of the 5' flanking region of the rat serine dehydratase gene.

For study of the mechanisms regulating the induction of serine dehydratase by various hormones in rat liver [Noda et al. (1988) J. Biol. Chem. 263, 14764-14768], we cloned the gene for this enzyme from a rat genomic library. The gene spans about 7.5 kilobases and consists of nine exons and eight introns. The exon-intron boundaries are consistent with the "GT-AG" rule. Southern blot analysis of rat genomic DNA suggested the presence of one copy of serine dehydratase gene per haploid genome. The 5' end of serine dehydratase mRNA is located 148 nucleotides upstream of the initiator methionine codon. ATG, determined by primer extension analysis and S1 nuclease mapping, although an alternative transcription initiation site(s) may be located a few bases downstream. The 5' flanking region of the gene lacks typical TATA and CCAAT sequences, but contains AATAAA and CATT sequences, at -25 to -20 and -54 to -51, respectively. Furthermore, there are five GC box-related sequences. There are three putative glucocorticoid-responsive elements and two copies of the CGTCA motif of the cAMP-responsive element upstream of the promoters. The 5' flanking sequence shows more than 98% homology with that reported by Ogawa et al. [(1988) Proc. Natl. Acad. Sci. U.S.A. 85, 5809-5813], but the first exons have different sequences. Another difference is that a segment of 108 nucleotides is located just upstream of exon 5 in the sequence reported here, but is included as an exon in the sequence of Ogawa et al. The possibility to producing two species of serine dehydratase mRNAs from a single gene by transcription from different sites and alternative splicing is discussed.

Developmental and growth-related regulation of expression of serine dehydratase mRNA in rat liver.

In rat liver, serine dehydratase mRNA is undetectable in the late prenatal period, but its level increases rapidly after birth to a transient peak, and then after decrease gradually increases again to a maximum 2 weeks after birth that is slightly higher than that of adult liver. To determine whether mature quiescent hepatocytes proliferate without loss of differentiated functions, we measured the serine dehydratase mRNA contents in regenerating liver and primary cultured hepatocytes from adult rats. Partial hepatectomy resulted in a dramatic decrease in the mRNA content within 24 h and then its recovery within a week. In subconfluent cultures of adult rat hepatocytes that did not grow even in the presence of mitogens, serine dehydratase mRNA was maintained at a high level. However, when the hepatocytes were cultured at low cell density without added mitogens, their serine dehydratase mRNA content decreases to a quarter of that of subconfluent cultures. The possibility that the expression of serine dehydratase mRNA is regulated in G0/G1 transition before entry into the S phase and the relationship of the mRNA with growth are discussed.