Effects of Conjugated Linoleic Acid (CLA) on Hormones and Factors Involved in Murine Ovulation (original) (raw)
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Effects of conjugated linoleic acid (CLA) on hormones and factors involved in urine ovulation
Conjugated linoleic acid is composed of polyunsaturated fatty acids (PUFA) that found in dairy products, beef and lamb. The aim of this study was to determine the effects of different doses of dietary CLA on systemic and local hormones and factors involved in ovulation. In this case-control study, 80 (50±2-day old) female mice were randomly divided into four groups. There were four replicates in each group and there were 5 mice in every replicate (20 mice, in total). The mice in the control group were fed with no CLA in their diet but the ones in the treatment group received 0.1, 0.3 and 0.5g/kg of CLA (replacing corn oil in the diet), respectively for 120 days. Later on, blood samples were obtained from the tails of animals that displayed estrus signs and estradiol, progesterone, LH, FSH, NO, leptin and TNFα were measured. Furthermore, the effects of CLA on the ovarian production of prostaglandins and NO were investigated. The data were analyzed by SAS software. CLA significantly d...
High α-linolenic acid and fish oil ingestion promotes ovulation to the same extent in rats
Nutrition Research, 2010
Prostaglandins (PG) have a regulatory influence on ovulation. α-Linolenic acid (ALA) vs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) differently influence PG biosynthesis. Whereas high EPA/DHA reduces PGE 2 , enhancing ovulation, we hypothesized that ALA would not affect ovulation. Our objective was to determine the effect of low and high ALA intake vs EPA/DHA on ovarian phospholipids, ovulation, and PG synthesis in rats. Following 27 days on diet and ovulation induction, ovaries were isolated and analyzed in 22 pups per diet. Ovarian phospholipid (n-3) polyunsaturated fatty acid (PUFA) incorporation increased with EPA/DHA ingestion. With significant ovarian (n-3) PUFA or EPA (P b .05) enrichment in the high-n-3 PUFA diets, ova release increased. Although high ALA did not enrich total (n-3), it increased ova release and tissue EPA over low ALA or control. Dietary EPA/DHA more effectively reduced ovarian arachidonic acid levels than dietary ALA. Dietary ALA increased PGF and very high intake reduced PGE, whereas EPA/DHA did not alter PGE or PGF. Enhanced ova release with high (n-3) PUFA intake may be induced via multiple mechanisms including reduced ovarian arachidonic acid. Significant ovarian retention of EPA and DHA enhanced ovulation with unchanged total PGE and PGF. Lack of change in PGE may have resulted from reduced PGE 2 combined with increased PGE 3. When EPA alone was elevated, PGE was reduced, whereas PGF was increased. Results indicate that very high ALA intake enhances ovulation similar to very high EPA/DHA ingestion, an effect potentially mediated via similar patterns of PGF 2 α and PGE 2 synthesis. Published by Elsevier Inc.
The Effect of Conjugated Linoleic Acid (CLA) on Male Reproductive Hormones in Mice
Spermatogenesis is a physiological reaction dependent to harmony of gonadotropins and steroid hormones activities. Conjugated linoleic acid is a group of long chain unsaturated fatty acids of a conjugated bound which are found in dairy products, beef and lamb. There are strong reasons that g/kg of food affects mediators involved in spermatogenesis. The aim of this study was determination of effect of various CLA doses on hormones and systemic factors of various CLA doses on hormones and systemic and local factors which affect spermatogenesis. Fifty mature male mice were divided in five groups (T 0 : control, T 1 : placebo and T 2-T 4 : treatment groups). Each group had two replications with four mice in each replication. Samples received control diet (0 g/kg of conjugated linoleic acid) or treatment diet (0.1, 0.3 and 0.5 g/kg of CLA) which was replaced with corn oil of diet. After 30 days, blood samples were taken and level of FSH, LH and testosterone hormones were measured. Data w...
Nutrition Research, 2009
Ovulation is a prostaglandin (PG)-dependent process. Although n-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) have differing effects in the body, both reduce PG synthesis. We hypothesized that dietary n-3 fatty acids and CLA would differentially alter ovarian PG profiles through reductions in expression of enzymes involved in PG biosynthesis resulting in enhanced ovulation. Our objectives were to determine how dietary stearidonic acid and eicosapentaenoic acid (EPA) at 0.3 g/100 g diet and mixed isomers of CLA at 0.7 g/100 g diet, human achievable levels with daily consumption of fish or beef and dairy products, respectively, would influence ovulation and ovarian cyclooxygenase-1 (COX-1) and COX-2 expression in ovulation-induced rats. After 27 days on diet and ovulation induction, ovaries were isolated and analyzed from 22 pups per diet. Eicosapentaenoic acid ingestion reduced ova release by 16% while increasing PGE 2 and PGF 2α release without altering COX-1 or COX-2 expression. Conversely, ovarian COX-1 expression was increased 135% with stearidonic acid ingestion associated with increased PGF 2α without altering PGE 2 or ova release. Conjugated linoleic acid ingestion reduced COX-2 expression to 65% of that in rats consuming control and EPA diets; however, without affecting ovulation or PGs. Although it is generally believed that the COX-2 is the primary COX involved in ovulation, these results demonstrated that the n-3 PUFA differently affect ovarian COX-1 expression and that this effect differs from CLA, which reduced COX-2 expression. Further, although ovarian PGF 2α is the primary PG altered by dietary n-3 PUFA, n-3 PUFA differentially influence ovarian PG biosynthesis and can decrease ova release, possibly induced through constitutive COX-1 enzyme expression.
Ingestion of n-3 polyunsaturated fatty acids and ovulation in rats
Reproduction, 1995
The effects of different ratios of dietary (n-3):(n-6) polyunsaturated fatty acids on prostaglandin E, prostaglandin F2\g=a\ and ovulation in rats were assessed. Dietary (n-3) polyunsaturated fatty acids were incorporated, by ovarian phospholipids with ovarian tissue enrichment, with (n-3) polyunsaturated fatty acids enhancing, and (n-6) polyunsaturated fatty acids reducing, the number of ova released in immature rats primed with pregnant mares' serum gonadotrophin and human chorionic gonadotrophin. Incorporation of (n-3) polyunsaturated fatty acids appeared to enhance ovulation by altering total prostaglandin E production. This effect may be induced by changes in the prostaglandin E3:E2 ratio and the synthesis of less biologically active prostaglandin E3, or by dilution of the anti-ovulatory properties attributable to prostaglandin E2. High incorporation of dietary (n-6) polyunsaturated fatty acids may lead to reduced ovulation through excessive production of prostaglandin E2. Prostaglandin E or F2\ g=a\ and alterations in tissue phospholipid composition inhibited progesterone release, and inhibition was independent of the series of prostaglandin produced. This study provides evidence that dietary lipids affect ovulation in rats with possible implications for reproduction in other vertebrates.
Journal of dairy science, 2009
The feeding of conjugated linoleic acid (CLA) supplements to early-lactation dairy cows has been shown to decrease milk fat synthesis and possibly improve reproductive performance. However, previously reported studies used too few animals to clearly establish the effect of CLA on reproduction. Our objective was to combine data from these studies to evaluate the association of CLA with time to first ovulation and time to conception using methods of survival analysis and overall success of pregnancy by logistic regression. A database was compiled of individual animal data (n = 212) from 5 controlled studies in which CLA had been supplemented to early-lactation dairy cows. Survival analysis incorporated both semi-parametric models (Cox proportional hazards) and parametric models (log-normal). The probability of cows becoming pregnant increased in a nonlinear manner as trans-10, cis-12 CLA dose increased, with the optimal dose predicted to be 10.1 g/d. At the optimal dose, the probabili...
Journal of Dairy Science, 2007
The objective of this study was to evaluate the mechanism of action through which conjugated linoleic acid (CLA) beneficially affects reproduction. Lactating Holstein cows (n = 45, 20 ± 1 DIM) were assigned to 1 of 3 treatments: 70 g/d of Ca salts of tallow (control); 63 g/d of lipid-encapsulated CLA providing 7.1 g/d of cis-9, trans-11 CLA and 2.4 g/d of trans-10, cis-12 CLA (CLA 75:25); or 76 g/d of lipid-encapsulated CLA providing 7.1 g/d each of cis-9, trans-11 and trans-10, cis-12 CLA (CLA 50:50). Supplements were top-dressed for 37 d, milk production and DMI were recorded daily, and blood samples were taken 3 times per week. At 30 ± 3 DIM, ovulation was synchronized in all cows with a modified Ovsynch protocol, and on d 15 of the cycle cows received an oxytocin injection; blood samples were obtained frequently to measure 13,14 dihydro, 15-keto PGF 2α . On d 16 of the cycle cows received a PGF 2α injection and ovarian follicular aspiration was performed 54 h later. Follicular fluid was analyzed for fatty acids, progesterone, and estradiol. Endometrial biopsies were taken before and again near the end of the supplementation period for fatty acid analysis. The CLA resulted in decreased milk fat content of 14.1 and 6.1% at wk 5 of treatment of CLA 50:50 and CLA 75:25, respectively. There were no differences in energy balance or plasma nonesterified fatty acids; however, plasma IGF-I was greater in cows supplemented with CLA 50:50. The CLA isomers were not detectable in 4253 endometrial tissue, but cis-9, trans-11 CLA tended to be greater in follicular fluid of supplemented cows. Response to the oxytocin challenge was not different among treatments. Progesterone during the early luteal phase and the estradiol:progesterone ratio in follicular fluid tended to be greater in cows supplemented with CLA 50:50. Overall, these results indicate that short periods of CLA supplementation do not alter uterine secretion of PGF 2α . The mechanism through which CLA affects reproduction may involve improved ovarian follicular steroidogenesis and increased circulating concentrations of IGF-I.
2012
Both n-3 polyunsaturated fatty acids (PUFAs) and conjugated linoleic acid (CLA) can alter biosynthesis of prostaglandins E 2 (PGE 2) and prostaglandin F2␣ (PGF 2␣), which have critical roles in animal reproduction. The objective was to determine the effects of dietary supplementation of fish oil (rich in n-3PUFAs; N3) or CLA on PGE 2 and PGF 2␣ production, ovulation rate, and litter size, using female transgenerational mice as an experimental model. Kunming mice were fed a diet that included 4% soybean oil (rich in n-6PUFAs; N6), 4% N3, or 4% CLA over three generations (ϳ 270 days). Ovarian concentrations of PGE 2 and PGF 2␣ , as well as the percentage of arachidonic acid (AA) in ovarian phospholipids, cyclooxygenase-2 (COX-2) enzyme activity and protein concentrations, were significantly lower in the N3 group than the N6 group. The number of ovulated oocytes and presumed zygotes were dramatically reduced, whereas the percentage of oocytes trapped in luteinized follicles was increased in the N3 group. Furthermore, litter sizes were decreased in the N3 vs. N6 groups (P Ͻ 0.05) in the second and third generations. In contrast, supplementation with CLA did not affect litter size or ovulation rate (P Ͼ 0.05). In conclusion, transgenerational supplementation with fish oil significantly decreased ovarian concentrations of AA and COX-2, concentrations of PGE 2 and PGF 2␣ , ovulation rate, and litter size in female mice.
Advanced Pharmaceutical Bulletin, 2013
Purpose: This study aimed to evaluate the possible estrogenic activity of some ingredients of Nigella sativa including Linoleic acid and Gama-Linolenic acid by vaginal cornification assay. Methods: Forty ovariectomized (OVX) rats, aged 16 weeks were allotted randomly to five groups: negative control (taking 1 ml olive oil/ day); positive control (taking 0.2 mg/kg/day Conjucated Equine Estrogen-CEE); experimental groups (taking 50 mg/kg/day Linoleic acid or 10 mg/kg/day Gamma Linolenic acid or 15mg/kg/day Thymoquinone ). All of supplements administered via intragastric gavage for 21 consecutive days. To assess estrogen like activity, vaginal smear was examined daily and serum estradiol was measured at baseline, after 10 days and at the end of experiment. Results: The significant occurrence of vaginal cornification cell (p<0.05) after Linoleic acid supplementation indicated estrogenic activity of Linoleic acid which was in consistency with serum estradiol level, but this effect was not as much as CEE. Gama-Linolenic acid also exist a few cornified cell in smear which was not significantly differ from those control group. Conclusion: Linoleic acid showed the beneficial effects on OVX rats' reproductive performance, thereby indicating its beneficial role in the treatment of the postmenopausal symptoms.
Polyunsaturated fatty acids and fertility in female mammals: an update
Both n-3 and n-6 polyunsaturated fatty acids (PUFAs) are derived from the diet, with concentrations in the reproductive tract reflecting dietary intake. PUFAs have multiple functions: as precursors to eicosanoids, regulators of steroid biosynthesis, inflammatory mediators and supplying energy (particularly in oocytes). The PUFA composition of cell membranes affects signalling pathways and susceptibility to oxidative damage. All of these roles may influence reproduction although results are often inconsistent between studies. Supplementation of cows with various PUFAs can increase the numbers of antral follicles although work on polyovular species (pigs, rodents) has usually failed to detect a change in ovulation rate. The anti-inflammatory actions of n-3 PUFAs may reduce follicular PGE production, delaying ovulation and allowing ovulatory follicles to grow larger and produce more steroid. Various PUFA supplements can reduce the interval from calving until first ovulation in cattle although the mechanism is uncertain. Both n-3 and n-6 PUFA supplements have been fed to various species before collecting oocytes for in vitro fertilization. Positive, negative and no effects on subsequent embryo development have all been reported. When PUFAs are added directly to oocyte maturation medium, high doses of linoleic acid (18 : 2 n-6) are consistently deleterious, while a-linolenic acid (18 : 3n-3) has been associated with positive outcomes. Uterine prostaglandin production regulates luteal regression and pregnancy recognition. Supplementary n-3 PUFAs have either increased or decreased PGF 2a production in different studies. There is some evidence that cattle and pigs fed a PUFA supplement post insemination may have an increased pregnancy rate. Review Methodology: CAB Abstracts and PubMed were searched for papers combining the term polyunsaturated (or PUFA) with keywords relating to female fertility (fertility, ovary, oocyte, follicular fluid, granulosa, ovulation, fertilization, luteal/corpus luteum and endometrium). Reference lists in recent relevant review articles and recent articles citing earlier reviews were also scrutinized. The main focus was on papers published since 2007.