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PubMed1976

Vitamin D metabolism: physiological regulation in egg-laying Japanese quail.

Homogenates of kidney removed from reproductivity active female Japanese quail were incubated with tritiated 25-hydroxyvitamin D3, and the metabolites were extracted and identified by chromatographic methods. Kidneys removed from birds with and without an egg in the oviduct revealed that ovulation results in enhanced production of 1, 25-dihydroxyvitamin D3, the active hormonal form of vitamin D3. Further examination of this phenomenon in relation to the ovulatory cycle revealed that 1, 25-dihydroxy-vitamin D3 production is enhanced throughout the 24 h following ovulation. Particularly important is the finding that its synthesis is already enhanced during the first 6 h after ovulation, at a time before any calcification of the egg shell begins. If, following oviposition, no ovulation occurs, 1, 25-dihydroxy-vitamin D3 production decreases rapidly and significantly within the first 6 h following oviposition. This study has revealed for the first time a physiological state, namely the reproductive period in the female bird, in which endogenous control over 1, 25-dihydroxyvitamin D3 production is exhibited without any previous manipulation, dietary or otherwise, of the animals.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

PubMed1998

Effect of butylated hydroxyanisole on catalase activity and malondialdehyde content in aging Zaprionus paravittiger (diptera).

Catalase activity and malondialdehyde (MDA) content were measured in whole body and mitochondrial homogenates of the banana fruit fly, Zaprionus paravittiger, fed on control and butylated hydroxyanisole (BHA, 10 mM) mixed diets. Catalase activity increased during the reproductive period and decreased thereafter with age. However, the MDA content increased with advancing age in both sexes. In general, females exhibited higher catalase activity and lower MDA content as compared to their male counterparts. BHA feeding increased catalase activity significantly during all age intervals in both sexes. Mitochondrial fractions had lower catalase activity and lower MDA content than whole body homogenates. However, the pattern of changes was similar in both homogenates with age as well as on antioxidant feeding. These results suggest that BHA strengthens the defense mechanism of the insects by increasing catalase activity and reducing MDA content which may be responsible for increased longevity of insects.

Aging↗

PubMed2004

Body mass index but not a polymorphism of the interleukin-1 receptor antagonist (IL-1 RA) gene is associated with age at natural menopause.

BACKGROUND: A genetic component of the onset of menopause has been described and several candidate genes have been identified. We hypothesized that carriage of a polymorphism of the interleukin-1 receptor antagonist gene (IL-1 RA) is associated with an early age at menopause. METHODS: In a prospective cohort study, 90 consecutive postmenopausal Caucasian women were genotyped by PCR for the presence of an 86-base pair tandem repeat polymorphism in intron 2 of IL-1 RA. RESULTS: We found that 36/90 (40%) women were homozygous for the wild-type allele 1 and 49/90 (54%) women were heterozygous for any of the variant alleles (1/2 [n = 44], 1/3 [n = 3], 2/3 [n = 2]). Two women (2%) were homozygous carriers of the variant allele 2. The wild-type allele 1 was identified on 119 of 180 chromosomes for an allele frequency of 0.66. The polymorphic alleles 2 and 3 were present on 56 and 5 chromosomes, respectively (allele frequencies 0.31 and 0.03, respectively). No correlation between the IL-1 RA genotype and the age at menarche and menopause, the length of the reproductive period, and the number of deliveries and miscarriages was ascertained. As to allele frequencies, homozygous and heterozygous carriers of the variant allele 2 had a median age at menopause of 50 (range 40-48) years, compared to 49.5 (range 39-56) years for women with no allele 2 (p value 0.41). Women with at least one allele 2 had a median age at menarche of 13 (range 10-16) years, compared to 13 (range 10-17) years for women with no allele 2 (p value 0.1). Decreasing body mass index, but not smoking, was correlated with an increasing age at natural menopause (r = -0.23, p = 0.04). CONCLUSIONS: Our preliminary data suggest that an 86-base pair tandem repeat polymorphism in intron 2 of IL-1 RA does not modulate the onset and cessation of menses in this cohort of Caucasian women.

Adult↗

PubMed1991

Risk factors in motor neuron disease: a case-control study.

A case-control study of risk factors in 512 cases of motor neuron disease (MND) and 512 controls, affected by other neurological diseases, was performed. Clinical history showed a significant increase in gastric ulcer and mechanical injuries among MND cases, whereas the frequencies of operations, poliomyelitis, malignancies and autoimmune diseases were similar for cases and controls. The women affected by MND had a later menarche and an earlier menopause; therefore, the reproductive period was significantly shorter, supporting a possible role of sexual hormones in the pathogenesis of MND. The analysis of occupations showed an increased number of farmers and also of subjects exposed to chemical products among MND cases.

Adult↗

PubMed1987

The effect of nicotine and alcohol on the fertility and life span of rats. A cytological analysis.

Inbred Fisher and Buffalo rats were exposed to nicotine and alcohol. Fertility was greatly reduced in both strains with nicotine treatments being much more deleterious than alcohol use. Fisher rats tolerated both toxins better than Buffalo rats. Both strains became 'extinct' after one generation of fetal and postnatal exposure to nicotine, but alcohol-ingesting Fisher rats had 3 or more generations of offspring. The total reproductive period was significantly shortened in both strains under the effect of both toxins, as was the total life span. The causes of the teratological effects of both toxins are inflammatory processes as evidenced by the presence of numerous lymphocytes and/or polymorphonuclear leukocytes. Their presence occurs earlier in nicotine than in alcohol use and earlier in Buffalo than in Fisher rats, but the damage done during nicotine treatment is reversible when the procedure is terminated. Inflammation is not transmitted to the newborn offspring of nicotine- or alcohol-treated mothers, but occurs in neonates during the nursing period or later. There is considerable individual variation in the tolerance to both toxins. Experimental results and clinical observations show a sufficient number of similarities to justify the use of experimental data as a model for further studies on human subjects.

Animals↗

PubMed1989

Treatment of uterine leiomyomata: past, present and future.

Hysterectomy for uterine leiomyomata can now be considered a safe procedure, but preoperative LHRH analogue administration greatly facilitates the surgical procedure, allowing myomectomy, when otherwise a hysterectomy may have been necessary. In selected cases, especially near the end of the reproductive period, LHRH analogues may become a valid alternative to hysterectomy.

Female↗

PubMed1992

Effect of propyl gallate feeding on glutathione content in ageing Zaprionus paravittiger (Diptera).

Glutathione content increased during the reproductive period and decreased thereafter up to the 43rd day of age in whole body as well as mitochondrial homogenates of ageing Zaprionus paravittiger. However, females exhibited higher levels of glutathione as compared to males. In whole body homogenates, propyl gallate (PG; 25 micrograms/ml) increased the glutathione content significantly up to the 22nd day of life whereas in mitochondria it increased during all age intervals in the two sexes with the exception of the 36th and 43rd day of survival in males. In conclusion, the higher level of glutathione on PG feeding might be one of the factors leading to the prolonged life span of flies.

Aging↗

PubMed1975

Fertility of the sibs of schizophrenic patients.

This investigation has provided evidence against the hypothesis that heterozygous carriers of schizophrenic gene have a reproductive advantage through enhanced fertility. An advantage arising from lower mortality between birth and the end of the reproductive period was not investigated, but should be examined before we search for other explanations of the apparently stable polymorphism of schizophrenia.

Age Factors↗

PubMed1997

Seasonal variation in uptake of short-chain neutral amino acid by red blood cells and hepatocytes in trout (Salmo trutta).

The present study shows that the capacity of trout (Salmo trutta) red blood cells (RBCs) and freshly isolated hepatocytes to take up short-chain neutral amino acids changes according to a seasonal pattern. Maximal amino acid uptake rates in RBCs were obtained in winter and spring, while minima were seen in summer and autumn. In contrast, the maximal rates for the freshly isolated hepatocytes were obtained in autumn and winter, and the minima were seen in spring and summer. In addition, by studying the uptake of glycine, evidence was found that the activities of the amino acids carriers ASC, asc and Gly in RBCs varied according to a seasonal rhythm. The activity of the ASC and asc systems changed in parallel with the global uptake of amino acids. Moreover, the RBC:plasma concentration ratio for certain substrates of these carriers (alanine, serine and glycine) varied accordingly. In contrast, the activity of the Gly system was modified inversely with respect to the overall amino acid uptake. The activity of the ASC system in freshly isolated hepatocytes was also seasonally modified, reaching a maximum in autumn, shortly before the reproductive period.

Amino Acids↗

PubMed2002

The effects of lipid location on non-invasive estimates of body composition using EM-SCAN technology.

We evaluated the effect of lipid location on body-composition estimation accuracy using electromagnetic scanning (EM-SCAN), a non-invasive [total body electrical conductivity (TOBEC)] method. Molds were constructed that simulated a 'general' small mammal, either 93% lean/7% lipid (control) or 82% lean/18% lipid (lipid-location groups). In the 18% lipid molds, we varied the location of the fat; simulating all the fat in the head, tail or midsection or simulating homogenous distribution. Comparisons were made between the EM-SCAN output of each lipid-location group, and multiple-regression techniques were performed to derive body-composition estimation equations for both lipid mass (M(L)) and fat-free mass (M(FF)). Device output varied significantly for all lipid-location groups even though all groups contained 18% body fat, showing a lipid-location effect on device output. Calibration equations derived for each lipid-location condition estimated both M(L) and M(FF) accurately, but an independent equation was required for each lipid-location condition. In situations where species significantly vary body fat content and location, for example during hibernation or reproductive periods, we suggest deriving a calibration equation that is more representative of the actual body composition to improve M(L) and M(FF) estimation accuracy using non-invasive EM-SCAN methods.

Adipose Tissue↗

PubMed1987

Changes in Wolfe mammographic patterns with aging.

Mammograms of 212 women were examined at a mean interval of 15 (range 11-17) years, to determine whether there was any change in Wolfe mammographic pattern with age. The mean age of the patients at repeat mammography was 52 (range 32-75) years. The DY pattern tended to change to P2 or P1 with age. Those in whom the DY pattern remained tended to be younger (mean age 47 years) than those who changed to P2 (57 years), or P1 (55 years). Women whose pattern changed from DY to N1 had a mean age of 42 years. These findings support the hypothesis that the perilobular connective-tissue elements are the structures responsible for the dense appearance of the DY breast, as these elements would be most active between 15 and 45 years (peak reproductive period) and tend to regress later.

Adult↗

PubMed2005

Uncoupling of longevity and telomere length in C. elegans.

The nematode Caenorhabditis elegans, after completing its developmental stages and a brief reproductive period, spends the remainder of its adult life as an organism consisting exclusively of post-mitotic cells. Here we show that telomere length varies considerably in clonal populations of wild-type worms, and that these length differences are conserved over at least ten generations, suggesting a length regulation mechanism in cis. This observation is strengthened by the finding that the bulk telomere length in different worm strains varies considerably. Despite the close correlation of telomere length and clonal cellular senescence in mammalian cells, nematodes with long telomeres were neither long lived, nor did worm populations with comparably short telomeres exhibit a shorter life span. Conversely, long-lived daf-2 and short-lived daf-16 mutant animals can have either long or short telomeres. Telomere length of post-mitotic cells did not change during the aging process, and the response of animals to stress was found independent of telomere length. Collectively, our data indicate that telomere length and life span can be uncoupled in a post-mitotic setting, suggesting separate pathways for replication-dependent and -independent aging.

Aging↗

PubMed2001

Urinary vasodilator and vasoconstrictor angiotensins during menstrual cycle, pregnancy, and lactation.

Since normal human pregnancy is characterized by normotension in the face of an increased renin-angiotensin-aldosterone system (RAAS), we evaluated the temporal pattern of urinary excretion of a novel vasodilator within this system, angiotensin-(1-7) (Ang-[1-7]), during the menstrual cycle, pregnancy, and lactation. The urinary profiles of Ang I, Ang II, human chorionic gonadotropin, 17beta-estradiol, and progesterone were also determined. During the menstrual cycle, urinary Ang-(1-7) and Ang II remained stable (mean cycle value: 94.6 +/- 11.3 and 11.4 +/- 1.1 pmol/g of creatinine, respectively) in nine females. In 10 normal pregnant women, urinary Ang-(1-7) and Ang II increased throughout gestation, averaging 1499.8 +/- 310 and 224.4 +/- 58 pmol/g of creatinine, respectively (p < 0.05) at wk 35 and falling during lactation to 394.0 +/- 95 and 65.7 +/- 20 pmol/ g of creatinine (p < 0.05), respectively. The Ang-(1-7)/Ang II ratio was unchanged in the different reproductive periods. During the menstrual cycle, Ang II and Ang-(1-7) correlated with 17beta-estradiol and progesterone using multivariate analysis (r = 0.31, p < 0.001) and r = 0.28, p < 0.02, respectively). During gestation, 17beta-estradiol and progesterone correlated with urinary Ang-(1-7) (r = 0.48, p < 0.001 and r = 0.47, p < 0.001, respectively) and Ang II (r = 0.24, p < 0.03 and r = 0.25, p < 0.03, respectively); by multiple regression, only Ang-(1-7) correlated with both steroids (r = 0.49,p < 0.001). The progressive rise of Ang-(1-7) throughout gestation, probably modulated by estrogen and progesterone, suggests a physiologic counterregulation within the RAAS.

Adult↗

PubMed2000

Characterization of SNP, a novel tissue- and phase-specific nuclear protein expressed during the proliferative phase in the oviduct of the lizard Podarcis sicula Raf.

The amino acid sequence of a novel tissue-and phase-specific nuclear protein (SNP) has been determined, after purification from the nuclei of the oviduct of the lizard Podarcis sicula Raf. during the reproductive period of the seasonal growth. SNP has a pI of 9.0 and contains 81 amino acid residues with a molecular weight of 9211.88 +/- 0.09. It shows a bipartite organization as the first 40 amino acids contain all 8 cysteinyl residues, while the last 41 amino acids contain 16 prolyl residues. Two more components have also been identified and characterized, with the first 79 amino acids matching SNP and missing one or two residues at the C-terminus. They have thus been named [des-(Ala81) SNP1] and [des-(Lys80-Ala81) SNP2], respectively. The molecular weights are 9140.21 +/- 0.83 for [des-(Ala81) SNP1] and 9011 +/- 0.09 for [des-(Lys80-Ala81) SNP2].

Amino Acid Sequence↗

PubMed1984

Steroid metabolism in corpora lutea of the western spotted skunk (Spilogale putorius latifrons).

The present study reports steroid metabolism by corpora lutea (CL) obtained from skunks with diapausing embryos ('delay' CL) and with activated embryos (activated CL). CL from both reproductive periods were incubated with various radioactive precursors. Control incubations without any tissue or with 50 microliter of packed skunk blood cells were also conducted simultaneously. Incubation of skunk CL with [3H]-pregnenolone for 3 h resulted in 36% of the precursor accumulating as progesterone. Metabolism of [3H]dehydroepiandrosterone (DHEA) to androstenedione proceeded with approximately the same amount of product accumulating (34-46%) as was observed in the conversion of pregnenolone to progesterone. These results suggest that delta 5 isomerase, 3 beta-hydroxysteroid dehydrogenase, is the most prominent enzyme in skunk CL. Metabolism of [3H]pregnenolone to 17 alpha-hydroxypregnenolone and [3H]progesterone to 17 alpha-hydroxyprogesterone occurred at low rates (1-7%), suggesting the presence of C21 steroid 17 alpha-hydroxylase in skunk CL. Aromatase activity, as estimated by measuring accumulation of oestradiol-17 beta from [3H]testosterone, was demonstrated in activated CL. These results suggest that skunk CL appear to metabolize steroids in a manner similar to CL of other mustelids such as the ferret and American badger.

17-alpha-Hydroxypregnenolone↗

PubMed1987

Characterization and androgenic regulation of major mRNAs coding for epididymal proteins in a lizard (Lacerta vivipara).

During the reproductive period (spring) under the control of testosterone the epididymis of the viviparous lizard secretes a group of major proteins with an approximate Mr of 19,000 named L protein(s). These proteins are recognized by a specific immunoserum and bind to the heads of spermatozoa. During spring, translation in reticulocyte lysate of RNA from secreting epididymis (stage 6) produced 5 immunoprecipitable bands with Mr values from 21,500 to 25,000. Such synthesis is undetectable during sexual rest in summer (stage 1). The 5 bands disappear when translation is performed in the presence of dog pancreas microsomes although a new band of Mr 19 000 becomes prominent. This suggests that synthesis of L protein involves two steps, i.e. synthesis of precursors (L preproteins) followed by a maturation process. At least 11 translation products (including L-preproteins) are involved in annual variations that follow the differentiation of the epididymal epithelial cells and their androgen dependency was studied by castration and in-vitro stimulation by testosterone. In these conditions, testosterone is able to control accumulation of RNA corresponding to L preproteins and to a translation product of Mr 29 000.

Animals↗

PubMed1996

Lipid and antioxidant changes in semen of broiler fowl from 25 to 60 weeks of age.

Spermatozoa and seminal plasma from cockerels at the beginning and end of their reproductive periods were examined for their lipid composition and associated antioxidant capacities. The significant reduction in concentration of spermatozoa with age was associated with a large increase in lipid concentrations in spermatozoa and in seminal plasma. This change in lipid concentration was accompanied by increases in the proportions of phospholipid and free cholesterol; in contrast, the proportions of these lipid moieties in seminal plasma were reduced. The major phospholipid fractions in the spermatozoa and seminal plasma were phosphatidyl choline and phosphatidyl ethanolamine. There was a large decrease with age in the proportion of phosphatidyl ethanolamine and a commensurate increase in that of phosphatidyl choline in the spermatozoa and seminal plasma. These major changes in phospholipid content were accompanied by a decrease in the amount of phosphatidyl serine in the spermatozoa and increases in phosphatidyl inositol and cardiolipin in both spermatozoa and seminal plasma. The reductions in the proportions of phosphatidyl ethanolamine were accompanied by considerable reductions in the content of the major polyunsaturated fatty acids 20:4 (n-6) and 22:4 (n-6). The changes in lipid composition owing to ageing were associated with a marked reduction within the spermatozoa of the major antioxidant enzyme glutathione peroxidase. The role of these changes in the specific combinations of polyunsaturated lipids and in antioxidant capacity in the reduction in fertility with age are discussed.

Aging↗

PubMed2006

17beta-estradiol induces Akt-1 through estrogen receptor-beta in the frog (Rana esculenta) male germ cells.

Several lines of evidence support the key role of estrogens in male fertility. Here, we investigate the regulation of the serine/threonine kinase Akt-1 in the frog (Rana esculenta) testis during the annual sexual cycle and, whether 17beta-estradiol (E2) exerts a role in the Akt-1 activity. Akt-1 has been shown to be the mediator of growth factor-dependent cell proliferation, survival, and metabolism in a variety of cell types. First, we demonstrate by immunohistochemistry, the presence of estrogen receptor-beta (ERbeta), and Akt-1 in the spermatogonia (SPG), spermatocytes (SPC), and spermatids (SPT). Western-blot analysis revealed that ERbeta isoform (molecular weight 55 kDa) was highly expressed in May (reproductive period) with respect to January and November (winter stasis); in parallel, Akt-1 (molecular weight 60 kDa) is highly phosphorylated (Ser-473) during the period of active spermatogenesis (May) compared with the winter stasis (January and November). In addition, in vitro experiments demonstrate that E2 treatment induces the activation of Akt-1, and this effect is counteracted by the anti-estrogen ICI 182-780. In conclusion, our data show that E2 induces Akt-1 phosphorylation (Ser-473) possibly via ERbeta in frog (R. esculenta) male germ cells.

Animals↗