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Molecular Reproduction and Development Jul 2014The timing and magnitude of exposure to preovulatory estradiol followed by post-ovulatory progesterone (periovulatory endocrine milieu) in cattle modulate endometrial...
The timing and magnitude of exposure to preovulatory estradiol followed by post-ovulatory progesterone (periovulatory endocrine milieu) in cattle modulate endometrial gene expression, histotroph composition, and conceptus development, but the mechanisms underlying this regulation remain unknown. Using an experimental model based on the modulation of follicle growth, this work aimed to evaluate if the polyamine metabolic pathway is regulated by the periovulatory endocrine milieu. Nelore cows were manipulated to ovulate small (n = 15) or large (n = 15) follicles, then the profiles of polyamines and their synthetic enzymes were compared between groups. Transcripts for the enzymes of this pathway, ornithine decarboxylase 1 (ODC1; the rate-limiting enzyme in polyamine biosynthesis) protein quantification, adenosylmethionine decarboxylase 1 (AMD1) protein immunolocalization, and concentrations of the different polyamines (putrescine, spermidine, and spermine) were respectively quantified by quantitative reverse-transcriptase PCR, immunoblotting, immunohistochemistry, and gas chromatography-mass spectrometry in both the endometrium and uterine flushing. No differences in gene and protein expression or concentration of polyamines were observed between groups. There were significant correlations between the relative abundance of ODC1 and spermidine/spermine N1-acetyltransferase 1 (SAT1) transcripts as well as between antizyme inhibitor 1 (AZIN1) and adenosylmethionine decarboxylase 1 (AMD1) transcripts. In conclusion, our results show that the polyamine metabolic pathway is present and functional, but not regulated by the periovulatory endocrine milieu in the bovine endometrium.
Topics: Adenosylmethionine Decarboxylase; Animals; Cattle; Diestrus; Endometrium; Female; Metabolic Networks and Pathways; Ornithine Decarboxylase; Polyamines; Progesterone
PubMed: 24659573
DOI: 10.1002/mrd.22323 -
The Journal of Veterinary Medical... Nov 2012Euglycemic-hyperinsulinemic glucose clamp (EHGC) method is a gold standard for assessing insulin resistance in humans. However, this method has yet to be commonly used... (Comparative Study)
Comparative Study
Characterization and comparison of insulin resistance induced by Cushing Syndrome or diestrus against healthy control dogs as determined by euglycemic- hyperinsulinemic glucose clamp profile glucose infusion rate using an artificial pancreas apparatus.
Euglycemic-hyperinsulinemic glucose clamp (EHGC) method is a gold standard for assessing insulin resistance in humans. However, this method has yet to be commonly used with dogs, due to the requirement of frequent blood sampling for glucose measurement and adjusting glucose infusion rate (GIR). The purpose of this study was to evaluate insulin resistance, induced either by Cushing Syndrome (CS) or diestrus in dogs, as determined by GIR by EHGC, using an artificial pancreas apparatus. Twenty animals were used in this study with ten (7 females and 3 males) serving as healthy controls, four (3 females, 1 male) diagnosed with CS, and six (all females) undergoing diestrus. A higher GIR value indicates increased insulin sensitivity and lower insulin resistance. GIR of healthy control animals was determined to be within a reference range of [10.6-21.3] with a median of 15.2 mg/kg/min. In comparison, the CS group had a median of 5.4 mg/kg/min; whereas the diestrus group exhibited a median of 8.9 mg/kg/min. Insulin resistant animals suffering from CS and undergoing diestrus demonstrated reductions of 65 and 40% in GIR, respectively; thus indicating differences in degree of insulin insensitivity can be discerned using the EHGC method.
Topics: Animals; Blood Glucose; Cushing Syndrome; Diestrus; Dog Diseases; Dogs; Female; Glucose; Glucose Clamp Technique; Immunoenzyme Techniques; Insulin; Insulin Resistance; Male; Pancreas, Artificial; Reference Values
PubMed: 22785565
DOI: 10.1292/jvms.12-0041 -
American Journal of Veterinary Research Jan 1989Receptors for estrogen and progesterone were measured in cytosols prepared from specimens of canine endometrium obtained at late proestrus, day 4 of estrus, day 2 of...
Receptors for estrogen and progesterone were measured in cytosols prepared from specimens of canine endometrium obtained at late proestrus, day 4 of estrus, day 2 of diestrus, and at 10 day intervals from days 10 through 80 of diestrus. Twenty nine adult bitches were used, with 2 to 4 dogs used at each time point. Concentrations of estradiol receptors measured in endometrial cytosols from late proestrus through day 10 of diestrus were similar (mean +/- SEM: 9.9 +/- 2.2, 10.5 +/- 1.2, 16.3 +/- 1.6, and 16.2 +/- 2.9 pmol/g of tissue at proestrus, day 4 of estrus, days 2 and 10 of diestrus, respectively). As serum concentrations of progesterone increased during early diestrus, the concentration of estradiol receptors decreased and were significantly (P less than 0.05) lower on days 30 (4.9 +/- 1.3 pmol/g of tissue) and 40 (3.7 +/- 0.6 pmol/g of tissue) of diestrus. After day 40 of diestrus, when serum concentrations of progesterone were approaching basal concentrations, the concentration of estradiol receptors increased and remained significantly (P less than 0.05) higher from days 60 to 80 of diestrus (day 60, 13.4 +/- 2.9; day 70, 15.7 +/- 1.7; day 80, 19.8 +/- 2.4 pmol/g of tissue). As observed for estrogen receptors, the concentration of endometrial receptors for progesterone also gradually increased from late proestrus (4.9 +/- 1.3 pmol/g of tissue) to day 2 of diestrus (6.4 +/- 0.3 pmol/g of tissue).(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Animals; Cytosol; Diestrus; Dogs; Endometrium; Estrus; Female; Proestrus; Progesterone; Receptors, Estradiol; Receptors, Progesterone
PubMed: 2919829
DOI: No ID Found -
Journal of the American Veterinary... Dec 2007To determine whether IM administration of exogenous oxytocin twice daily on days 7 to 14 after ovulation blocks luteolysis and causes prolonged function of corpora lutea...
OBJECTIVE
To determine whether IM administration of exogenous oxytocin twice daily on days 7 to 14 after ovulation blocks luteolysis and causes prolonged function of corpora lutea (CL) in mares.
DESIGN
Prospective study.
ANIMALS
12 mares.
PROCEDURES
Beginning on the day of ovulation (day 0), jugular blood samples were collected every other day until day 40 for determination of progesterone concentration. On day 7, mares (n = 6/group) were treated with saline (0.9% NaCl) solution (control group) or oxytocin. Beginning on day 7, control mares received 3 mL of sterile saline solution every 12 hours, IM, and oxytocin-treated mares received 60 units of oxytocin every 12 hours, IM, through day 14. Mares were considered to have prolonged CL function if progesterone concentration remained > 1.0 ng/mL continuously through day 30.
RESULTS
The proportion of mares with prolonged CL function was significantly higher in the oxytocin-treated group (6/6), compared with the control group (0/6). All control mares underwent luteolysis by day 16, at which time their progesterone concentrations were < 1.0 ng/mL. In contrast, all 6 oxytocin-treated mares maintained progesterone concentrations > 1.0 ng/mL continuously through day 30.
CONCLUSIONS AND CLINICAL RELEVANCE
IM administration of 60 units of oxytocin twice daily on days 7 to 14 after ovulation was an efficacious method of inhibiting luteolysis and extending CL function in mares. Disrupting luteolysis by administering exogenous oxytocin during diestrus appears to be a plausible and practical method of long-term suppression of estrus in mares.
Topics: Animals; Area Under Curve; Corpus Luteum; Diestrus; Female; Horses; Injections, Intramuscular; Luteolysis; Ovulation; Oxytocics; Oxytocin; Progesterone; Prospective Studies
PubMed: 18081527
DOI: 10.2460/javma.231.12.1864 -
Journal of Animal Science Apr 1983To study the possible role of ovarian androgens in regulation of follicle stimulating hormone (FSH) secretion in the cycling mare, five mature, intact mares were treated...
To study the possible role of ovarian androgens in regulation of follicle stimulating hormone (FSH) secretion in the cycling mare, five mature, intact mares were treated with testosterone (20 micrograms/kg of body weight) daily during estrus; five control mares received safflower oil on the same schedule. Mares were teased for estrus and samples of jugular blood were drawn daily through one full estrous cycle. Concentrations of FSH in plasma were measured by a newly developed radioimmunoassay based on anti-ovine FSH serum and radioiodinated equine FSH. Testosterone treatment during estrus had no effect on duration of estrus, diestrus or the total cycle. Concentrations of FSH in plasma during estrus were unaffected by testosterone treatment. However, FSH concentrations in testosterone-treated mares were elevated (P less than .05) compared with controls during mid-diestrus (d 6 through 11). The magnitude and timing of the LH peaks were unaffected by treatment, as was the day on which the first elevated progesterone concentration occurred. These data are consistent with a model of FSH secretion in which ovarian androgens cause an accumulation of FSH in the pituitary during estrus in preparation for the surges that occur in FSH secretion during diestrus.
Topics: Animals; Diestrus; Estrus; Female; Follicle Stimulating Hormone; Horses; Luteinizing Hormone; Pregnancy; Progesterone; Testosterone
PubMed: 6406417
DOI: 10.2527/jas1983.564911x -
Hormones and Behavior Jun 1995Food restricting lactating rat dams over the first 2 weeks of lactation results in a prolongation of the period of lactational diestrus. Such food restriction has not...
Food restricting lactating rat dams over the first 2 weeks of lactation results in a prolongation of the period of lactational diestrus. Such food restriction has not only a direct effect on the dam but also the pups are undernourished, and the pattern of dam-litter contact is also changed. In a series of studies, we investigated the effects of nursing undernourished pups and the change in dam-litter interaction on the prolongation of lactational diestrus. While nursing undernourished pups in the last 2 weeks of lactation is sufficient to extend lactational diestrus in ad lib-fed dams nursing well-nourished pups in the last 2 weeks of lactation is not necessary for the prolongation of lactational diestrus seen in food-restricted dams. Further, neither nursing underfed pups nor increased nest time in the first 2 weeks postpartum are necessary factors for the prolongation of lactational diestrus in food-restricted dams.
Topics: Animals; Body Temperature Regulation; Body Weight; Diestrus; Energy Intake; Energy Metabolism; Female; Food Deprivation; Lactation; Maternal Behavior; Nutritional Status; Pregnancy; Psychophysiology; Rats; Rats, Wistar; Social Environment; Sucking Behavior
PubMed: 7557920
DOI: 10.1006/hbeh.1995.1012 -
Biology of Reproduction Jan 1989The relationship between the amount and duration of administration of estradiol benzoate (EB) to newborn female rats and the induction of sterility was examined in 407...
The relationship between the amount and duration of administration of estradiol benzoate (EB) to newborn female rats and the induction of sterility was examined in 407 animals. Vaginal smear patterns were classified into 3 types according to the incidence of vaginal proestrus and estrus over a 10-day period: persistent estrous (PE), persistent diestrus (PD), and intermediate (INT), so that the changes in vaginal smear patterns could be analyzed quantitatively. Incidence of the PE pattern was most frequent in the rats that received a single injection of 10 micrograms EB on the day of birth (Day 1). Almost all of the animals receiving 10 daily injections of 10 micrograms EB from Day 1 showed persistent diestrus until at least 100 days of age. In the rats that were given 5 daily injections of 10 micrograms EB Day 1 through Day 5, or a single injection of 100 micrograms EB on Day 3, the incidence of the PD pattern was high at 41-60 days of age, but later the PD-type was replaced by the PE pattern of vaginal smears. In the rats that were treated with 5 daily injections of 10 micrograms EB from Day 1 through Day 5 and were ovariectomized on Day 22, a slight but significant increase in the level of luteinizing hormone in plasma was noted after administration of EB and progesterone on Day 100 but not on Day 50. These results indicated that neonatal injections of EB induce sterility, but the effect is dependent on the amount of EB injected and length of time over which the injections are given.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Aging; Animals; Animals, Newborn; Diestrus; Estradiol; Estrus; Female; Luteinizing Hormone; Ovariectomy; Rats; Rats, Inbred Strains; Vaginal Smears
PubMed: 2923954
DOI: 10.1095/biolreprod40.1.96 -
American Journal of Obstetrics and... Aug 1963
Topics: Animals; Diestrus; Estrus; Female; Pentobarbital; Pharmacology; Rats; Research; Sex; Sex Characteristics
PubMed: 14047505
DOI: 10.1016/s0002-9378(16)35237-1 -
The Anatomical Record Jul 1947
Topics: Animals; Corpus Luteum; Desoxycorticosterone Acetate; Diestrus; Estrus; Female; Humans; Rats
PubMed: 20251224
DOI: 10.1002/ar.1090980307 -
Theriogenology Oct 2006To better understand the process of slow luteal regression of the nonpregnant cycle in dogs and the acute luteolysis that occurs prepartum, the present study...
To better understand the process of slow luteal regression of the nonpregnant cycle in dogs and the acute luteolysis that occurs prepartum, the present study investigated in vitro PGF2alpha production by the endometrium, corpus luteum and placental explants obtained at known times of the cycle from pregnant bitches (days 63, 64 and immediately postpartum; day 0 = estimated day of the ovulatory LH surge) and from nonpregnant diestrus bitches (approximately days 65, 75 and 85). Both basal PGF2alpha production and its production in the presence of the protein kinase C (PKC) stimulator 12,13-phorbol dibutyrate (PDBu) were determined. For PDBu-supplemented incubations, mean PGF2alpha production (pg/mL/mg/6 h) by endometrium explants of the nonpregnant bitches in late diestrus was highest on day 65 (205 +/- 87) and reduced to low levels (38 +/- 17 and 11 +/- 11) on days 75 and 85, respectively. The production by corpus luteum explants from these bitches was significantly less on day 65 (46 +/- 14) than that of the day 65 endometrium explants, and was slightly increased on day 85 (103 +/- 52). The corresponding mean PGF2alpha production by the endometrium explants of pregnant bitches was on average much greater (i.e., two to three-fold) compared to nonpregnant bitches (P < 0.01) and involved high concentrations at day 64 (1523 +/- 467) and postpartum, compared to somewhat lower levels on day 63 (830+/-65); luteal PGF production (165 +/- 4) was also higher than in nonpregnant bitches around day 65. For pregnant bitches, PGF production per gram of tissue in the endometrium explants was greater than for the CL or placenta explants (180 +/- 37). Therefore, the endometrium of the pregnant bitch has an increased capability to produce PGF2alpha immediately prepartum, which on a tissue weight basis, exceeds that of either corpora lutea or the placenta. However, assuming a larger mass of placental tissue in vivo, we inferred that the placenta may contribute substantially to peripheral PGF concentrations.
Topics: Animals; Corpus Luteum; Diestrus; Dinoprost; Dogs; Endometrium; Enzyme Activators; Female; Hybridization, Genetic; Male; Phorbol 12,13-Dibutyrate; Placenta; Pregnancy; Protein Kinase C; Tissue Culture Techniques
PubMed: 16469369
DOI: 10.1016/j.theriogenology.2006.01.037