Uterine Glycogen Research Articles

Endometrial glycogen metabolism during early pregnancy in mice.

Glucose is critical during early pregnancy. The uterus can store glucose as glycogen but uterine glycogen metabolism is poorly understood. This study analyzed glycogen storage and localization of glycogen metabolizing enzymes from proestrus until implantation in the murine uterus. Quantification of diastase-labile periodic acid-Schiff (PAS) staining showed glycogen in the glandular epithelium decreased 71.4% at 1.5 days postcoitum (DPC) and 62.13% at DPC 3.5 compared to proestrus. In the luminal epithelium, glycogen was the highest at proestrus, decreased 46.2% at DPC 1.5and 63.2% at DPC 3.5. Immunostaining showed that before implantation, glycogen metabolizing enzymes were primarily localized to the glandular and luminal epithelium. Stromal glycogen was low from proestrus to DPC 3.5. However, at the DPC 5.5 implantation sites, stromal glycogen levels increased sevenfold. Similarly, artificial decidualization resulted in a fivefold increase in glycogen levels. In both models, decidualization increased expression of glycogen synthase as determine by immunohistochemistry and western blot. In conclusion, glycogen levels decreased in the uterine epithelium before implantation, indicating that it could be used to support preimplantation embryos. Decidualization resulted in a dramatic increase in stromal glycogen levels, suggesting it may have an important, but yet undefined, role in pregnancy.

Glycogen in the uterus and fallopian tubes is an important source of glucose during early pregnancy†.

Pregnancy loss is common during the peri-implantation period in mammals when glucose is required for both embryonic development and decidualization of the endometrium. As the uterus cannot synthesize glucose, all glucose must come directly from maternal circulation as needed or transiently stored as the macromolecule glycogen. Glycogen acts as a glucose reservoir, storing up to 55 000 glucose moieties per molecule. Endometrial glycogen concentrations are correlated with fertility in humans, indicating that glycogen is an essential source of glucose during early pregnancy. In humans and primates, endometrial glycogen concentrations peak during the luteal phase due to progesterone. In contrast, in rats and mink, estradiol triggers an accumulation of uterine glycogen during proestrus and estrus. In mated rats, the glycogen content of the endometrium increases again after implantation due to high levels of glycogen stored in the decidua. In mink, endometrial glycogen reserves are localized in the uterine epithelia at estrus. These reserves are mobilized before implantation, suggesting they are used to support embryonic growth. Uterine glycogen concentrations continue to decrease after implantation in mink, probably due to a lack of decidualization. How ovarian steroids stimulate glycogenesis in the endometrium is unclear, but current evidence suggests that estradiol/progesterone interacts with insulin or insulin-like growth factor signaling. In summary, endometrial glycogen is an essential source of glucose during the peri-implantation period. More work is needed to characterize differences among species, elucidate the fate of the glucose liberated from glycogen, and understand how ovarian steroids regulate glycogen metabolism in the uterus.

Glycogen metabolism in mink uterine epithelial cells and its regulation by estradiol, progesterone and insulin

Glycogen content in mink uterine glandular and luminal epithelia (GE and LE) is maximal during estrus and is depleted before implantation while embryos are in diapause. Uterine glycogen synthesis in vivo is stimulated by estradiol (E2) while its mobilization is induced by progesterone (P4). Nevertheless, treatment of an immortalized mink uterine epithelial cell line (GMMe) with E2 did not affect glycogen production. Interestingly, insulin alone significantly increased synthesis of the nutrient and glycogen content in response to insulin + E2 was greater than for insulin alone. Our objectives were to determine: 1) If insulin receptor protein (INSR) is expressed by mink uterine GE and LE in vivo and if the amount differs between estrus, diapause and pregnancy; 2) if E2, P4 or insulin regulate insulin receptor gene (Insr) expression by GMMe cells, and 3) if E2 and P4 act independently to regulate glycogen metabolism by GMMe cells and/or if their effects are mediated in part through the actions of insulin. The mean (±S.E.) percent INSR content of uterine epithelia was greatest during diapause (GE: 15.65 ± 0.06, LE:16.56 ± 1.25), much less during pregnancy (GE: 2.53 ± 0.60, LE:2.25 ± 0.32) and barely detectable in estrus (GE: 0.03 ± 0.01, LE:0.02 ± 0.01). Glycogen concentrations in GMMe cells increased 10-fold in response to insulin and 20-fold with insulin + E2 when compared to controls. Expression of Insr was increased 2-fold by insulin and insulin + E2 when compared to controls and there was no difference between the two hormone treatments, indicating that E2 does not increase Insr expression in insulin-treated cells. To simulate E2-priming, cells were treated with Insulin + E2 for 24 h, followed by the same hormones + P4 for the second 24 h (Insulin + E2 → P4) which resulted in Insr and glycogen levels not different from controls. Similarly, cells treated with Insulin + P4 resulted in glycogen concentrations not different from controls. We conclude that the glycogenic actions of E2 on GMMe cells are due to increased responsiveness of the cells to insulin, but not as a result of up-regulation of the insulin receptor. Glycogen mobilization in response to P4 was the result of decreased glycogenesis and increased glycogenolysis occurring concomitantly with reduced Insr expression. Mink uterine glycogen metabolism appears to be regulated in a reproductive cycle-dependent manner in part as a result of the actions of E2 and P4 on cellular responsiveness to insulin.

Activity based evaluation of a traditional Ayurvedic medicinal plant: Saraca asoca (Roxb.) de Wilde flowers as estrogenic agents using ovariectomized rat model

Ethnopharmacological relevanceSaraca asoca (Roxb.) de Wilde, Ashok, is a popular traditional plant used for gynecological disorders. In India, the juice of Ashok flowers is traditionally consumed as a tonic by women in case of uterine disorders. But despite the use, its estrogenic potency is not yet evaluated and thus lacks the scientific recognition and acclaim. Aim of the studyThis study is designed to investigate the estrogenic potential of standardized ethanolic extract of Saraca asoca flowers (SAF) using ovariectomized (OVX) female albino Wistar rat model. Materials and methodsSaraca asoca flowers were extracted in ethanol using hot maceration technique and the extract was standardized in terms of content of four phytoestrogens like quercetin, kaempferol, β-sitosterol and luteolin using HPTLC technique. Safety of the extract was evaluated at a dose of 2000mg/kg body weight in female albino Wistar rats as per the OECD guidelines. Bilateral ovariectomy surgery was performed for the excision of both the ovaries. The OVX animals were treated with the ethanolic extract of SAF at three dose levels- 100mg/kg, 200mg/kg and 400mg/kg body weight in distilled water as a vehicle, orally once a day for two weeks. Estradiol valerate was employed as a modern drug for comparative evaluation of the results. Estrogenic potency was studied by assaying the activities of serum and plasma marker enzymes and hormones viz. G6PDH, LDH, 17β-estradiol, progesterone along with cholesterol, triglycerides and HDL, and vaginal cornification. The uterotrophic effect was evaluated by studying the histoarchitecture of the uterus, effect on uterine weight and changes in the levels of uterine glycogen content. ResultsHPTLC revealed the presence of markers like quercetin, kaempferol, β-sitosterol and luteolin from the ethanolic extract of SAF. The content of the four markers was found to be 1.543mg/g, 0.924mg/g, 4.481mg/g and 2.349mg/g, respectively. SAF extract was found to be safe at an oral dose of 2000mg/kg body weight in rats. Among the three doses administered to ovariectomized rats, treatment with high dose was found to be more efficacious when compared with ovariectomized rats. ConclusionThe findings of this study firmly support the estrogenic potency of ethanolic extract of SAF which may be by the reason of phytoestrogens.

Estradiol stimulates glycogen synthesis whereas progesterone promotes glycogen catabolism in the uterus of the American mink (Neovison vison).

Glycogen synthesis by mink uterine glandular and luminal epithelia (GE and LE) is stimulated by estradiol (E2 ) during estrus. Subsequently, the glycogen deposits are mobilized to near completion to meet the energy requirements of pre-embryonic development and implantation by as yet undetermined mechanisms. We hypothesized that progesterone (P4 ) was responsible for catabolism of uterine glycogen reserves as one of its actions to ensure reproductive success. Mink were treated with E2 , P4 or vehicle (controls) for 3 days and uteri collected 24 h (E2 , P4 and vehicle) and 96 h (E2 ) later. To evaluate E2 priming, mink were treated with E2 for 3 days, then P4 for an additional 3 days (E2 →P4 ) and uteri collected 24 h later. Percent glycogen content of uterine epithelia was greater at E2 + 96 h (GE = 5.71 ± 0.55; LE = 11.54 ± 2.32) than E2 +24 h (GE = 3.63 ± 0.71; LE = 2.82 ± 1.03), and both were higher than controls (GE = 0.27 ± 0.15; LE = 0.54 ± 0.30; P < 0.05). Treatment as E2 →P4 reduced glycogen content (GE = 0.61 ± 0.16; LE = 0.51 ± 0.13), to levels not different from controls, while concomitantly increasing catabolic enzyme (glycogen phosphorylase m and glucose-6-phosphatase) gene expression and amount of phospho-glycogen synthase protein (inactive) in uterine homogenates. Interestingly, E2 →P4 increased glycogen synthase 1 messenger RNA (mRNA) and hexokinase 1mRNA and protein. Our findings suggest to us that while E2 promotes glycogen accumulation by the mink uterus during estrus and pregnancy, it is P4 that induces uterine glycogen catabolism, releasing the glucose that is essential to support pre-embryonic survival and implantation.

Evaluation of the estrogenic activity of Indian medicinal plants in immature rats.

Introduction:The objective of the study was to evaluate the estrogenic activity of four Indian medicinal plants Saraca indica (Si), Symplocos racemosa (Sr), Cyperus rotundus (Cr), Terminalia arjuna (Ta), a marketed preparation of Si (Aśokāriṣṭa) and a combination of Si + Sr using an experimental model of estrogenicity.Materials and Methods:After approval of the institutional animal ethics committee, 22 day old female rats (n = 54) were randomly allocated to 9 groups – Group 1 and Group 2: Vehicle controls, Group 3: Ethinyl estradiol, Group 4: Si (270 mg/kg), Group 5: Sr (270 mg/kg), Group 6: Cr (540 mg/kg), Group 7: Ta (270 mg/kg), Group 8: Ashokarishta (4 ml/kg), Group 9: Si + Sr (135 mg/kg). Variables studied were: Body weight, uterine weight, relative uterine weight, presence of vaginal opening, histomorphology of the uterus and total uterine glycogen content. Parametric data were analyzed using one-way ANOVA and the categorical data were analyzed using Chi-square test.Results:All animals in the ethinyl estradiol group showed a significant change in all the variables. None of the individual test drugs, neither the marketed preparation produced change in any of the variables. The plant drug combination also did not produce a change in any of the variables studied except in histomorphology wherein it caused a slight increase in the height of the luminal epithelium of the uterus (P < 0.05 vs. Group 1).Conclusion:The plant drugs Si, Sr, Cr, Ta and Aśokāriṣṭa did not demonstrate estrogenic activity in the immature rat model. The plant drug combination Si + Sr showed questionable estrogenic activity which needs to be evaluated in further studies.

Uterine glycogen metabolism in mink during estrus, embryonic diapause and pregnancy.

We have determined uterine glycogen content, metabolizing enzyme expression and activity in the mink, a species that exhibits obligatory embryonic diapause, resulting in delayed implantation. Gross uterine glycogen concentrations were highest in estrus, decreased 50% by diapause and 90% in pregnancy (P ≤ 0.05). Endometrial glycogen deposits, which localized primarily to glandular and luminal epithelia, decreased 99% between estrus and diapause (P ≤ 0.05) and were nearly undetectable in pregnancy. Glycogen synthase and phosphorylase proteins were most abundant in the glandular epithelia. Glycogen phosphorylase activity (total) in uterine homogenates was higher during estrus and diapause, than pregnancy. While glycogen phosphorylase protein was detected during estrus and diapause, glycogen synthase was almost undetectable after estrus, which probably contributed to a higher glycogenolysis / glycogenesis ratio during diapause. Uterine glucose-6-phosphatase 3 gene expression was greater during diapause, when compared to estrus (P ≤ 0.05) and supports the hypothesis that glucose-6-phosphate resulting from phosphorylase activity was dephosphorylated in preparation for export into the uterine lumen. The relatively high amount of hexokinase-1 protein detected in the luminal epithelia during estrus and diapause may have contributed to glucose trapping after endometrial glycogen reserves were depleted. Collectively, our findings suggest to us that endometrial glycogen reserves may be an important source of energy, supporting uterine and conceptus metabolism up to the diapausing blastocyst stage. As a result, the size of uterine glycogen reserves accumulated prior to mating may in part, determine the number of embryos that survive to the blastocyst stage, and ultimately litter size.

The Effects of Estradiol and Catecholestrogens on Glycogen Catabolism and Glucose Mobilization in the Uterus of the Mink (Neovison vison).

Embryonic development prior to formation of the placenta depends in part on uterine glandular secretions (histotroph) that are rich in carbohydrates, including glycogen. In mink, total uterine glycogen concentrations decrease 55% between estrus and the peri-implantation period, presumably to meet the metabolic demands of developing embryos. Estradiol-17beta (E2) stimulates uterine glycogen production and circulating E2 levels peak during proestrous and decline thereafter. We have shown that the effects of E2 are mediated in part through the catecholestrogens: 2-hydroxycatecholestradiol (2-OHE2) and 4-hydroxycatecholestradiol (4-OHE2) produced by the endometrium. It is however, unknown what is responsible for glycogen catabolism as the time of implantation draws near. While progesterone concentrations are increasing at this time, exogenous progesterone stimulated uterine glycogen accumulation in mink with intact ovaries. Although E2 levels are significantly reduced during most of the peri-implantation period, a transitory peak in E2 secretion occurs near the expected time of implantation. It is therefore possible that E2 and/or catecholestrogens facilitate both glycogen synthesis and breakdown. Therefore, to investigate the effects of these steroids on glycogen catabolism and glucose mobilization, our objectives were to determine the effects of E2, 2-OHE2 and 4-OHE2 on (1): uterine glycogen content and (2): gene expression levels for glycogen-synthase, glycogen-phosphorylase, and glucose-6-phosphatase. Mink (N=24) were ovariectomized and assigned at random to one of four groups: 1 = Controls, 2 = E2, 3 = 2-OHE2, and 4 = 4-OHE2. Animals were injected sc once daily with hormone (40ug/kg BW) in sesame seed oil, or oil only (controls) for 3 consecutive days. On day four, mink were sacrificed and uteri collected. Total uterine glycogen concentrations (mg/g dry wt) were increased 8-fold by E2 and 4-OHE2 and 4-fold by 2-OHE2, compared to controls (P<0.05). Interestingly, the percent glycogen content of the glandular epithelium was increased 4 to 5 fold by 4-OHE2 and E2 (P<0.05), but was not different between 2-OHE2 and controls. Expression of glycogen-synthase mRNA did not differ between E2, 4-OHE2 and controls, but was reduced 5-fold in response to 2-OHE2 (P<0.01). Uterine glycogen-phosphorylase mRNA expression was increased 3-fold by E2 and 4-OHE2, and 10-fold by 2-OHE2 (P<0.01). The expression of glucose-6-phosphatase mRNA was greatest in response to 2-OHE2, followed by 4-OHE2 and then E2 (P<0.05). We conclude that E2 and/or catecholestrogens influence both glycogen synthesis and breakdown, perhaps as a result of different concentrations or exposure time. Although 4-OHE2 is considered to be a more potent estrogen than 2-OHE2, our data show that 2-OHE2 had a greater effect than E2 and 4-OHE2 on the expression of all glycogen metabolizing genes investigated here. It is possible that as the time of implantation approaches, the production and/or sensitivity of the uterus to 2-OHE2 predominates over both 4-OHE2 and E2, promoting glycogen catabolism and glucose mobilization. Such a mechanism, could serve to regulate the release of glucose from uterine glycogen reserves, providing a source of nutrition to the developing embryos, which may be essential for implantation and reproductive success. (Funded by Fur Commission USA and NIH INBRE P20RR016454) (poster)

Uterine Glycogen Metabolism During the Reproductive Cycle of the Mink (Neovison vison).

Uterine Glycogen Metabolism During the Reproductive Cycle of the Mink (Neovison vison).

The effects of estradiol and catecholestrogens on uterine glycogen metabolism in mink (Neovison vison)

Glycogen is a uterine histotroph nutrient synthesized by endometrial glands in response to estradiol. The effects of estradiol may be mediated, in part, through the catecholestrogens, 2-hydroxycatecholestradiol (2-OHE2) and 4-hydroxycatecholestradiol (4-OHE2), produced by hydroxylation of estradiol within the endometrium. Using ovariectomized mink, our objectives were to determine the effects of estradiol, 4-OHE2, and 2-OHE2 on uterine: 1) glycogen concentrations and tissue localization; 2) gene expression levels for glycogen synthase, glycogen phosphorylase, and glycogen synthase kinase-3B; and 3) protein expression levels for glycogen synthase kinase-3B (total) and phospho-glycogen synthase kinase-3B (inactive). Whole uterine glycogen concentrations (mean ± SEM, mg/g dry wt) were increased by estradiol (43.79 ± 5.35), 4-OHE2 (48.64 ± 4.02), and 2-OHE2 (41.36 ± 3.23) compared to controls (4.58 ± 1.16; P ≤ 0.05). Percent glycogen content of the glandular epithelia was three-fold greater than the luminal epithelia in response to estradiol and 4-OHE2 (P ≤ 0.05). Expression of glycogen synthase mRNA, the rate limiting enzyme in glycogen synthesis, was increased by 4-OHE2 and 2-OHE2 (P ≤ 0.05), but interestingly, was unaffected by estradiol. Expression of glycogen phosphorylase and glycogen synthase kinase-3B mRNAs were reduced by estradiol, 2-OHE2, and 4-OHE2 (P ≤ 0.05). Uterine phospho-glycogen synthase kinase-3B protein was barely detectable in control mink, whereas all three steroids increased phosphorylation and inactivation of the enzyme (P ≤ 0.05). We concluded that the effects of estradiol on uterine glycogen metabolism were mediated in part through catecholestrogens; perhaps the combined actions of these hormones are required for optimal uterine glycogen synthesis in mink.

The Expression of Uterine Glycogen Metabolizing Enzymes in Response to Catecholestrogens Differs Between Parous and Nulliparous Rats: A possible Explanation for Larger Litter Sizes with Increasing Parity?

The Expression of Uterine Glycogen Metabolizing Enzymes in Response to Catecholestrogens Differs Between Parous and Nulliparous Rats: A possible Explanation for Larger Litter Sizes with Increasing Parity?

Evaluation of estrogenic activity of alcoholic extract of rhizomes of Curculigo orchioides

The rhizomes of Curculigo orchioides Gaertn. (Amaryllidacea) is an important Ayurvedic as well as Unani drug. It is present in several drug formulations used in the treatment of menorrhagia and other gynecological problems. In this study, we conducted a comparative study of estrogenic activity of alcoholic extract of Curculigo orchioides with diethylstilbestrol in bilaterally ovariectomized young albino rats. Bilaterally ovariectomized albino rats were divided into five groups ( n = 9) receiving different treatments, consisting of vehicle (0.6% w/v sodium carboxy methyl cellulose), ethanolic extract of rhizomes of Curculigo orchioides at three different doses (viz., 300, 600, 1200 mg/kg body weight) and standard drug diethylstilbestrol (DES) at a dose of 2 mg/kg body weight. All these were administered orally daily for 7 days. Estrogenic activity was assessed by taking percentage vaginal cornification, uterine wet weight, uterine glycogen content and uterine histology as parameters of assessment. Alcoholic extract of Curculigo orchioides showed a significant increase in percentage vaginal cornification, uterine wet weight ( P < 0.001), uterine glycogen content ( P < 0.001) and a proliferative changes in uterine endometrium compared to the control.

P.3.f.002 The 5-HT6 receptor antagonists, SB271,046 and SB258,585, enhance social memory and cholinergic transmission in rats: a comparison with 5-HT1A receptor partial agonists

Glycogen is a uterine histotroph nutrient synthesized by endometrial glands in response to estradiol. The effects of estradiol may be mediated, in part, through the catecholestrogens, 2-hydroxycatecholestradiol (2-OHE2) and 4-hydroxycatecholestradiol (4-OHE2), produced by hydroxylation of estradiol within the endometrium. Using ovariectomized mink, our objectives were to determine the effects of estradiol, 4-OHE2, and 2-OHE2 on uterine: 1) glycogen concentrations and tissue localization; 2) gene expression levels for glycogen synthase, glycogen phosphorylase, and glycogen synthase kinase-3B; and 3) protein expression levels for glycogen synthase kinase-3B (total) and phospho-glycogen synthase kinase-3B (inactive). Whole uterine glycogen concentrations (mean ± SEM, mg/g dry wt) were increased by estradiol (43.79 ± 5.35), 4-OHE2 (48.64 ± 4.02), and 2-OHE2 (41.36 ± 3.23) compared to controls (4.58 ± 1.16; P ≤ 0.05). Percent glycogen content of the glandular epithelia was three-fold greater than the luminal epithelia in response to estradiol and 4-OHE2 (P ≤ 0.05). Expression of glycogen synthase mRNA, the rate limiting enzyme in glycogen synthesis, was increased by 4-OHE2 and 2-OHE2 (P ≤ 0.05), but interestingly, was unaffected by estradiol. Expression of glycogen phosphorylase and glycogen synthase kinase-3B mRNAs were reduced by estradiol, 2-OHE2, and 4-OHE2 (P ≤ 0.05). Uterine phospho-glycogen synthase kinase-3B protein was barely detectable in control mink, whereas all three steroids increased phosphorylation and inactivation of the enzyme (P ≤ 0.05). We concluded that the effects of estradiol on uterine glycogen metabolism were mediated in part through catecholestrogens; perhaps the combined actions of these hormones are required for optimal uterine glycogen synthesis in mink.

P.3.f.001 Association study of the glycogen synthase kinase-3β (GSK-3β)-50T/C polymorphism with schizophrenia; association with depression and cognitive impairment

Glycogen is a uterine histotroph nutrient synthesized by endometrial glands in response to estradiol. The effects of estradiol may be mediated, in part, through the catecholestrogens, 2-hydroxycatecholestradiol (2-OHE2) and 4-hydroxycatecholestradiol (4-OHE2), produced by hydroxylation of estradiol within the endometrium. Using ovariectomized mink, our objectives were to determine the effects of estradiol, 4-OHE2, and 2-OHE2 on uterine: 1) glycogen concentrations and tissue localization; 2) gene expression levels for glycogen synthase, glycogen phosphorylase, and glycogen synthase kinase-3B; and 3) protein expression levels for glycogen synthase kinase-3B (total) and phospho-glycogen synthase kinase-3B (inactive). Whole uterine glycogen concentrations (mean ± SEM, mg/g dry wt) were increased by estradiol (43.79 ± 5.35), 4-OHE2 (48.64 ± 4.02), and 2-OHE2 (41.36 ± 3.23) compared to controls (4.58 ± 1.16; P ≤ 0.05). Percent glycogen content of the glandular epithelia was three-fold greater than the luminal epithelia in response to estradiol and 4-OHE2 (P ≤ 0.05). Expression of glycogen synthase mRNA, the rate limiting enzyme in glycogen synthesis, was increased by 4-OHE2 and 2-OHE2 (P ≤ 0.05), but interestingly, was unaffected by estradiol. Expression of glycogen phosphorylase and glycogen synthase kinase-3B mRNAs were reduced by estradiol, 2-OHE2, and 4-OHE2 (P ≤ 0.05). Uterine phospho-glycogen synthase kinase-3B protein was barely detectable in control mink, whereas all three steroids increased phosphorylation and inactivation of the enzyme (P ≤ 0.05). We concluded that the effects of estradiol on uterine glycogen metabolism were mediated in part through catecholestrogens; perhaps the combined actions of these hormones are required for optimal uterine glycogen synthesis in mink.

Effect of mancozeb on ovarian compensatory hypertrophy and biochemical constituents in hemicastrated albino rat ☆

Mancozeb a carbamate fungicide was administered orally at doses of 500, 600, 700, and 800 mg/kg/day to normal hemicastrated virgin rats for 15 consecutive days to examine the effect on ovarian hypertrophy. Sham-operated and hemicastrated control rats were administered a similar quantity of olive oil. The vaginal smear and body weight of the rats were recorded daily and rats were sacrificed on the Day 16. The ovary, uterus, kidney, adrenal, spleen, liver, lungs, heart, thymus, and thyroid were removed and weighed. The left ovary from each animal was serially sectioned and stained for histologic studies. The hemicastrated control rats revealed a significant increase in relative ovarian weight with 66.3% hypertrophy. Treatment with 700 and 800 mg/kg/day mancozeb revealed a decrease in ovarian hypertrophy with 28.2 and 22.8% hypertrophy, respectively. There was no significant change in the number of estrous cycles and duration of each phase of the estrous cycle with 500 mg/kg/day mancozeb. However, there was a decrease in the number of estrous cycles, duration of proestrus, estrus, and metestrus with concomitant significant increase in the duration of the diestrus phase with 600, 700, and 800 mg/kg/day mancozeb treatment. There was a significant decrease in the number of healthy follicles with concomitant increase in the number of atretic follicles at higher doses of mancozeb. There were no significant changes in the body and organ weight with 500, 600, 700, and 800 mg/kg/day of mancozeb. The levels of protein, glycogen, total lipid, phospholipid, and neutral lipid were elevated in the liver, uterus, and ovary after hemicastration. Protein, glycogen, total lipid, phospholipid, and neutral lipid were not significantly changed in the liver, uterus, and ovary after 500 mg/kg/day mancozeb. However, treatment with 600, 700, and 800 mg/kg/day mancozeb showed a significant decrease in the levels of protein, glycogen, total lipid, phospholipid, and neutral lipid in the liver, uterus, and ovary, with the exception of liver total lipid and uterine glycogen. In addition to the decrease in the compensatory ovarian hypertrophy, mancozeb treatment reduced the number of healthy follicles with a concomitant increase in the number of atretic follicles. This finding plus disruption of the estrous cycle may be due to a direct effect on the ovary or the hypothalamo–hypophysial–ovarian axis.

Reversible Antifertility Effects of Benzene Extract of Papaya Seed on Female Rats

The effects of benzene extract from papaya seeds and those of withdrawal (30 days each) were investigated on the physiology of ovaries and uterus of rats and their fertility. The results revealed that the treatment did not affect ovarian steroidogenesis. On the other hand, uterine glycogen, protein and enzymes were altered which rendered the internal milieu hostile for implantation. The extract manifested an antifertility effect in treated animals. The withdrawal of treatment resulted in recovery of all the induced effects of the extract and restored fertility. Hence, the antifertility effects of the extract were transient and reversible. This is the first report of its kind using the benzene extract of the seed.

Effect of chronic underfeeding on uterine glycogen of rats. Influence of indomethacin and nordihydroguaiaretic acid

Glycogen values in uterine strips isolated from normal-fed estrous or diestrous rats, or from rats fed a restricted diet (50% of normal food intake for 25 days) were measured. Determinations were made immediately after killing (0 time or post-isolation) as well as after incubation in glucose-free medium (60 min time or post-incubation). The post-incubation levels of glycogen in the uteri from normal-fed animals diminished significantly in comparison to post-isolation values, and this decrement was not modified by the addition of indomethacin, nordihydroguaiaretic acid or exogenous prostaglandins E 1, E 2 or F 2α. In rats fed a restricted-diet, the initial glycogen values (0 time) were significantly lower than in normal-fed controls, but did not decline further after incubation in glucose-free medium (60 min time). The addition of indomethacin, acetylsalicylic acid or of nordihydroguaiaretic acid led to a significant fall in the glycogen levels, and exogenous PGE 1, PGE 2 or PGF 2α failed to alter the effects of the inhibitors. The values of PGE and PGF prostaglandins release to the medium by the uterus from restricted-diet rats did not differ from those obtained in the experiments with normal-fed animals. Administration of 17-β estradiol to restricted-diet rats led to suppression of the effects of this diet on the glycogen concentration. The above results indicate that in rats subjected to a prolonged period of dietary restriction, the uterine glycogen becomes responsive to the effects of cyclooxygenase and lipoxygenase inhibitors, suggesting the operation of some regulatory mechanism during critical periods of nutrition.

Spontaneous activity in vitro of the uterine horns of unilaterally pregnant rats. Relations with glycogen and triglycerides levels

Effects of the placental implantation on the in vitro spontaneous contractile activity of uterine strips incubated in a glucose-free KRB medium, and its relationship with the glycogen and triglycerides tissue levels, have been analysed using unilaterally pregnant rats. The spontaneous activity increased with pregnancy duration, both in the implantation zone (Impl) and the interembryonic segment (Inter) of the pregnant horn. It increased in the contralateral sterile horn (SH) also. Activity was significantly greater in SH and Inter than in Impl, at the same stage of pregnancy. Uterine glycogen, but not triglycerides, appeared to be the substrate used to sustain contractile activity, as its concentration was greater in Impl, the relatively quiescent zone.

Effect of partial starvation onin vitrospontaneous activity and glycogen levels of uterine smooth muscle from pregnant and non pregnant rats

Effects of a restricted-diet (50% of the normal feeding) given during 14 days, on the isometric developed tension (IDT) of uterine horns isolated from pregnant and non pregnant (diestrous) rats, incubated in a KRB-medium without glucose, were explored. In 14 days-pregnant rats, dietary restriction did not alter the contractile activity with respect to normal-fed controls. Besides, levels of uterine glycogen, immediately after killing the animals or after 60 min incubation, remained unaltered. In advanced pregnancy partial starvation led to decay of spontaneous contractile activity after 60 min incubation. However, the considerable increment in the levels of tissue glycogen at 0 time was not modified, nor its decrease at the end of the in vivo experimental period. In non-pregnant rats, a reduced feeding did not alter the development of contractile tension, but exerted a pronounced effect on the glycogen levels: these were significantly lower than controls at 0 time but suffered no changes after 60 min on in vitro activity. Indomethacin appeared to have no effect on the spontaneous contractile activity of 14 days-pregnant rats. It significantly depressed contractility in 21 days-pregnant rats. Indomethacin did not modify the levels of glycogen in any of the experimental groups.

Metabolic effects of a “carbohydrate-free” diet in the pregnant rat

Abstrac The effects on selected metabolic indicators of carbohydrate deprivation in pregnant rats was studied. Pregnant rats were fed a diet containing 13% casein, either 69.5% (CON) or 0% (CD) carbohydrate, and oleic acid to make the diets isocaloric. Diets were fed beginning on Day 0 of pregnancy. A restricted intake group (RI) was also included to indicate the effect of reduced food intake. On days 8, 10, and 12 of pregnancy, animals were killed and liver, uterus and blood were harvested. Glycogen and glucose-6-phosphatase in endometrial tissue, glycogen in liver, ketone bodies in whole blood, and glucose, total lipid, cholesterol, urea nitrogen and alanine in plasma were determined. In CD dams, fetal resorption reached 75% by day 12 of gestation but only 35% in RI dams. Carbohydrate deprivation and restricted intake resulted in depleted liver glycogen. CD dams were hypoglycemic and hyperlipemic. Plasma alanine did not differ among the 3 groups and plasma urea was elevated in the CD group only on day 12. CD dams were markedly hyperketonemic. Neither uterine glycogen nor uterine glucose-6-phosphatase activity differed between the 3 groups, suggesting that uterine glycogen utilization was not the limiting factor in embryonic survival. Hypoglycemia, hyperketonemia or both may be related to the reproductive failure in CD rats.