Cystic Degeneration in Porcine Ovaries - Second Communication: Concentrations of Progesterone, Estradiol-17β, and Testosterone in Cystic Fluid and Plasma; Interpretation of the Results

Contents: The content of progesterone, estradiol-17β, and testosterone of plasma and cystic fluid was determined in 79 sows with ovarian cysts. The average progesterone concentration of sows with dark corpora lutea (CL) was higher than of sows with pale or absent CL (39.4 vs. 8.7 vs. 8.0 ng/ml plasma; p < 0.001; and 7512 vs. 3644 vs. 2723 ng/ml cystic fluid, respectively; p < 0.001). The cystic fluid of animals with oligocystic ovaries (10 cystslanimal) had a significant higher progesterone concentration in comparison to potycystic animals (7200 vs. 3682 ng/ml; p < 0.001). Testosterone and estradwl-17β levels in plasma and in cystic fluid of polycystic animals were significantly higher in comparison to oligocystic animals (Plasma-Testosterone: p < 0.01; Plasma-Estradwl: p < 0.05; Cyst-Testosterone: p < 0.01; Cyst-Estradiol: p < 0.001). In oligocystic ovaries testosterone in cysts exceeded the estradiol-17β levels, whereas in polycystic ovaries the situation was vice versa (p < 0.001).
It is suggested that cystic ovarian degeneration in the sow is not exclusively a gradually progressing process, rather then a complex syndrome with three components, were characterized by a separate course of development (oligocystic, polycystic. oligo-polycystic syndrome).     

Effect of the gonadotrophins treatment on morphological alterations in ovary and peripheral plasma concentrations of steroid hormones in gilts

The present study was designed to examine the influence of gonadotrophins treatment on the ovarian morphology changes and plasma concentrations of steroid hormones in peripheral blood. The experiment was performed on sexually pubertal gilts (Large White x Landrace) of similar age (7-8 months) and body mass (100-110 kg) with two controlled subsequent estrous cycles. The animals were randomly divided into four groups: two control consisting of pigs with the luteal phase (n = 9, the 10th day of the estrous cycle) and the follicular phase (n = 6, the 20th day of the estrous cycle) and two experimental ones consisting of animals with both mentioned periods (n = 7 and n = 9) treated with gonadotrophins (PMSG and hCG). The gilts in the luteal phase were injected (s.c.) with gonadotrophins at a daily dose of PMSG 400 and hCG 200 IU from the 16th to the 27th day (the 6th day of the next estrous cycle). The gilts in the follicular phase, were injected with the same dose of gonadotrophins but from the 8th to the 19th day of the estrous cycle. Plasma concentrations of P4, A4, T, E1, E2 and metabolite of PGF2 alpha-PGFM were determined by radioimmunoassay (RIA) method. Injections of PMSG and hCG in both experimental groups produced several times enlarged: weight, size and volume of ovaries and alterations in a number of structural elements as compared with those found in the control animals. The morphological elements presented in ovaries: corpora haemorrhagica, corpora lutea, regular and atretic follicles and first of all cysts by distinctly differentiation thickness of the walls are characteristic for cystic ovarian degeneration. Plasma concentrations all determined hormones after gonadotrophins treatment in experimental groups were increased except E1 (insignificant decrease) in luteal phase as compared with those found in the control groups. Statistically significant increase (p < 0.001) in plasma concentrations of P4, A4, and T in both experimental groups and E2 (p < 0.001) in luteal phase were noted. In peripheral plasma concentrations increase of E1 and E2 in follicular phase of the estrous cycle were insignificant.     

Bovine Uterine,Cervical and Ovarian Cytosol Estrogen and Progesterone Receptor Concentrations in Cystic Ovarian Disease

Bovine cytosol estrogen (ERC) and progesterone receptor (PRC) concentrations were measured simultaneously in various regions of the uterus and in ovarian stromal tissue in cows with cystic ovarian disease (follicular cysts), arid the concentrations compared with those in animals with normal cycles. In cystic ovarian disease, ERC concentrations in endometrium (550 fmol/mg cytosol protein (c.p.)) and in myometrium (405) were significantly higher than in control animals. Very high PRC contents were measured in the endometrium (3115) and myometrium (2761) of cows with cystic ovarian disease. In control animals, PRC concentrations in the endometrium and myometrium were significantly lower than in diseased animals. No statistical differences were observed in ERC or PRC contents between the endometrium and the myometrium in cows with cystic ovarian disease. ERC and PRC concentrations in the uterine cervix and ovaries were low compared to those detected in the uterus. Bovine serum estradiol-17ß concentrations were higher (p<0.001) in cows with cystic ovarian disease than in control animals in postpartum anestrus or during the normal estrous cycle. Serum sex hormone-binding globulin (SHBG) concentrations were of the same magnitude as in control cows during their estrous cycles. These findings show that long standing low endogenous progesterone and elevated estradiol concentrations in serum are associated with elevated ERC and PRC concentrations in bovine uterus.     

Luteal toxicity evaluation in rats

The corpora lutea (CL) are endocrine glands that form in the ovary after ovulation and secrete the steroid hormone, progesterone (P4). P4 plays a critical role in estrous and menstrual cycles, implantation, and pregnancy. The incomplete rodent estrous cycle stably lasts 4–5 days and its morphological features can be distinguished during each estrous cycle stage. In rat ovaries, there are two main types of CL: newly formed ones due to the current ovulation (new CL), and CL remaining from prior estrous cycles (old CL). In the luteal regression process, CL were almost fully regressed after four estrous cycles in Sprague-Dawley rats. P4 secretion from CL in rodents is regulated by the balance between synthesis and catabolism. In general, luteal toxicity should be evaluated by considering antemortem and postmortem data. Daily vaginal smear observations provided useful information on luteal toxicity. In histopathological examinations, not only the ovaries and CL but also other related tissues and organs including the uterus, vagina, mammary gland, and adrenal glands, must be carefully examined for exploring luteal changes. In this review, histological and functional characteristics of CL in rats are summarized, and representative luteal toxicity changes are presented for improved luteal toxicity evaluation in preclinical toxicity research.     

Immunohistochemical Expression of Growth Factors in the Follicular Wall of Normal and Cystic Ovaries of Sows

The expression of growth factors was evaluated immunohistochemically in normal and cystic ovaries of sows. The immunohistochemically stained area (IHCSA) was quantified by image analysis to analyse the expression of these proteins in the follicular wall of secondary, tertiary and cystic follicles. IGF‐I immunoreactivity was strong in the granulosa cell layer (GC), moderate in the theca interna (TI) and mild in the theca externa (TE) of the normal follicles. There was severe reduction of the labelling to IGF‐I in the GC of the follicular and luteinized cysts. In the normal follicles, the reactivity for IGF‐II was very similar to pattern noted in IGF‐I. There was reduction of the IHCSAs in the GC of the follicular and luteinized cysts, but the decrease was not significant. The staining of the IGF‐II in the TI and TE of the cysts was increased, in comparison with normal follicles. The IHCSAs for VEGF were higher in the GC and TE of the normal follicles in contrast to TI, but this difference was noted only in the tertiary follicle. The VEGF reactivity increased in the GC of the cysts, in relation to normal follicles. The results of the current study show that the formation of ovarian cysts in sows is associated with alterations in the immunohistochemical expression of some growth factors.     

Relationships between ultrasonographic image attributes, histomorphology and proliferating cell nuclear antigen expression of bovine antral follicles and corpora lutea ex situ.

The aim of this study was to examine the relationships between quantitative ultrasonographic image characteristics, histological attributes and cell proliferating ability of bovine antral follicles and corpora lutea (CL) ex situ. Bovine ovaries (n = 30) from animals at various reproductive states (metoestrus-early dioestrus, n = 8; mid-dioestrus, n = 12; oestrous phase of peripubertal heifers, n = 6; and pregnancy, n = 4) were collected at the slaughterhouse. High-resolution ultrasonographic images of the ovaries were obtained in the water bath, digitized and subjected to computerized image analyses. The analyses utilized line and spot techniques designed to determine pixel values of the follicular wall (the largest follicles >2 mm in diameter in each ovary) and CL, respectively. Individual ovarian structures were dissected and processed for histology and immunohistochemical detection of proliferating cell nuclear antigen (PCNA). The mean follicular diameter was negatively correlated with total cell density (r = -0.45, p < 0.05), granulosa layer thickness (r = -0.67, p < 0.001) and the percentage of PCNA-positive cells (r = -0.57, p < 0.001). Numerical pixel values and heterogeneity of the follicular wall were positively correlated with total cell density (r = 0.42, p < 0.05 and r = 0.62, p < 0.05; respectively), granulosa layer thickness (both r = 0.39, p < 0.05), and the percentage of PCNA-positive cells (r = 0.54, p < 0.01 and r = 0.69, p < 0.001, respectively). Estimates of cell density and proliferating cell index were not correlated with the ultrasonographic image attributes of CL. We conclude that follicular size and echotextural variables, as determined by computer-assisted image analysis of ovaries ex situ, are reliable markers of the histophysiological properties of bovine antral follicles, but the ultrasonographic characteristics are not indicative of cell density and proliferation in the bovine CL.     

Effects of Neodymium:Yttnum Aluminum Garnet Laser Irradiation on Endometrium and on Endometrial Cysts in Six Mares

Effects of neodymium:yttrium aluminum garnet (Nd:YAG) laser irradiation on equine endometrium were evaluated In vitro and in six mares with endometrial cysts. The Nd:YAG laser was applied to six endometrial sites, in each of five uterine specimens, with power densities of 5659 to 33,954 J/cm². Depth of tissue ablation was measured and graded on histologic sections of the tissue lesions. Power density had a significant effect on the depth of tissue ablation (p < .001). Grade 3 lesions (full-thickness ablation of the endometrium) were created with energy densities of 16,977 to 33,954 J/cm². Six mares had endometrial cysts treated by photoablation. Two of the four mares that were reproductively sound but barren, despite appropriate breeding, produced foals after treatment. One mare remained reproductively unsound after treatment, and another mare that was treated postpartum was bred successfully.     

Anovulation and plasma hormone concentrations after administration of dexamethasone during the middle of the luteal phase in sows undergoing estrous cycles

The effect of glucocorticoids on early follicular growth in sows undergoing normal estrous cycles was evaluated by administration of dexamethasone during the middle of the luteal phase. Plasma specimens were obtained for measurement of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone, and estradiol-17 beta concentrations. Fifteen sows were used. Control sows (n = 5) were given physiologic saline solution twice daily from day 9 to day 14 of the estrous cycle. Sows of the second group (n = 5) were given dexamethasone (30 micrograms/kg of body weight, IM) similarly, and those of the third group (n = 5) were given dexamethasone plus gonadotropin-releasing hormone (GnRH; 50 micrograms at 6-hour intervals, IV). Plasma specimens, obtained twice daily from day 8 through day 26, indicated that progesterone production and luteal regression were not inhibited by any of the 3 treatment regimens. Although preovulatory plasma estradiol concentration increased in control sows, such was not observed in the sows treated with dexamethasone or dexamethasone plus GnRH (P less than 0.01). Ovulation, with formation of corpora lutea, occurred in gilts given saline solution. Dexamethasone administration resulted in persistence of 19 to 41 follicles/ovary (2 to 4 mm in diameter), and dexamethasone-plus-GnRH treatment resulted in 6 to 18 follicles/ovary (5 to 6 mm in diameter). Plasma was obtained at 15-minute intervals for 12 hours to compare the effect of treatment on hormone concentrations on day 12 of the estrous cycle with the values on day 8.(ABSTRACT TRUNCATED AT 250 WORDS)     

High-Frequency Jet Ventilation in Anesthetized, Paralyzed Dogs and Cats Via Transtracheal and and Endotracheal Tube Routes

The ability of the SAV 6 high-frequency jet ventilator to effectively ventilate three anesthetized, paralyzed cats (3.2–4.2 kg), two small dogs (7.2 and 10.0 kg), six medium-sized dogs (20.5–25.0 kg), and three large dogs (36.0–43.0 kg) via a 14-gauge (dogs) or a 16-gauge (cats) catheter placed percutaneously into the trachea via the cricothyroid membrane or into a preplaced endotracheal tube was evaluated. The lowest driving pressure within the range of 0.25 to 2.0 kg/cm² (1 kg/cm²= 14.2 psi) and the highest cycle rate within the range of 60 to 240 per minute that would generate a PaCO₂ of 30 ± 3 mm Hg were determined.
All animals could be ventilated to a PaC0₂ of 30 ± 3 mm Hg by the endotracheal tube and transtracheal route, except the largest dogs, which couid be ventilated to an average PaC0₂ of 36 mm Hg by the transtracheal route. The transtracheal route consistently required higher driving pressures and lower cycle rates than did the endotracheal tube route. Cats could be ventilated with a driving pressure of 0.25 kg/cm²; small dogs could be ventilated with 0.5 to 1.0 kg/cm₂; medium-sized dogs with 1.0 to 1.5 kg/cm²; and large dogs with 1.5 to 2.0 kg/cm².
The SAV 6 high-frequency jet ventilator can effectively ventilate cats and dogs (7.2–43.0 kg) via a transtracheal catheter and an endotracheal tube.     

Impact of Exogenous ACTH During Pro-Oestrus on Endocrine Profile and Oestrous Cycle Characteristics in Sows

Sows housed in freely moving groups have elevated cortisol levels until the rank order is established, which takes place within approximately 48 h. The aim of this investigation was to study the effect of repeated administration of synthetic adrenocorticotropic hormone (ACTH; Synacthen Depot), during the follicular phase (pro-oestrus) on oestrus, ovulation and endocrine parameters. Four multiparous sows were used. Follicular growth and ovulation were recorded by ultrasonography. The first oestrous cycle after weaning was used as control cycle. Onset of oestrus in the sow occurs 3-4 days after the time when plasma progesterone reaches a concentration of 8 nmol/l. The progesterone profile in the control cycle of the individual sow was used for estimation when the ACTH injections should start. In the third pro-oestrus ACTH (2.5 microg/kg) was given via an indwelling catheter every 2 h for 48 h. The sows were euthanased 4-6 days after onset of the third oestrus and the ovaries were examined. Cortisol levels were elevated during the treatment period (p < 0.05). The second cycle, in which the sows were injected with ACTH, was prolonged with 2.5 days compared with the control cycle (p < 0.05). The oestradiol pattern during oestrus was similar in the control and the treatment cycle in ovulating sows. Three sows had ovulated (fresh corpora lutea), but the ovaries contained additionally one or several luteinized follicles/cysts. In conclusion, ACTH administration during pro-oestrus caused a prolongation of the oestrous cycle and a disturbed follicular development.     

Ovarian Structure in Mice Lines Selected for Weight

Selection for body weight at 49 day of age ( s and h , downward selected lines; s' and h' , upward selected lines) affected reproductive traits in CF1 mice lines. The objective of this study was to compare ovarian structures in females of these lines, as well as in unselected controls (Line t ). The number of ovarian follicles ( N ), follicle diameter (FD), number of corpora lutea (CL), litter size (LS), and body weight ( W ), were recorded. There were significant differences among lines for N , FD, CL, LS and W ; means values for the lines with the greatest difference for post-pubertal females were: N _s  = 19.3 and N _s'  = 32.7; FD _h'   = 161.7 and FD _s'  = 178.2; CL _h  = 10.3 and CL _s'  = 21.9; LS _s  = 6.0 and LS _h'  = 11.1; W _h  = 18.9 and W _s'  = 32.4. There were also differences between positive lines; Line s' had a higher proportion of large follicles in pre-pubertal females, a greater capacity to convert these follicles into CL, but a lower capacity to maintain embryos until term than Line h' . For negative lines, Line h apparently had a reduced incidence of embryonic loss when compared with Line s . In conclusion, selection for body weight modified ovarian structure, as well as reproductive efficiency.     

Estimation of superovulation response in donor cows

Estimates were made of the superovulation response in donor cows using ovarian size, the number of corpora lutea (palpated per rectum) and blood progesterone levels. Neither the estimated number of corpora lutea nor ovarian size gave a satisfactory prediction of superovulation response. There was a large discrepancy between the number of corpora lutea present on the ovaries of nine superovulated cows (166) and the estimated number (106). All the corpora lutea on superovulated ovaries were smaller than normal (1.95 g). Blood progesterone levels at the time of embryo recovery were correlated with both the number of corpora lutea on the superovulated ovaries (r = 0.9, P less than 0.001) and the weight of the corpora lutea (r = 0.95, P less than 0.001). There were 67 embryos and ova recovered from the nine donors, representing 40 per cent of the actual and 63 per cent of the palpated corpora lutea. However, neither ovarian size, the number of corpora lutea nor blood progesterone levels were correlated with embryo production.     

The asymmetric distribution of ovarian functional structures in cattle

The results of continually repeated transrectal palpations, performed in 168 post partum periods, 383 estrous cycles and 178 early pregnancies, were used to describe and to discuss the left-right distribution of ovarian functional structures. In cycling as well as in pregnant cattle, anovulatory interestral follicles and estrous follicles or corpora lutea in the mean were all distributed at 41% and 59% on the left and right ovaries respectively. No signs were found indicating that the position of functional structures would be influenced by local interactions between follicles and corpora lutea. At least for cyclic ovarian activity, and in early pregnancy, the interrelationship observed between the locations of these structures could be put down to the normally increased activity of the right ovary. After delivery, the first follicles preferentially became discernible on the ovary opposite to the previously pregnant uterine horn. But, as from the 4th follicle p.p. onward, the distribution of new ovarian structures again agreed with the one of the ensuing reproductive stages. After calving, probably the position of new follicles is temporally influenced by direct signals from the uterine horns affected differently by pregnancy. Several observations indicate that the factors causing asymmetrical ovarian activity could exert a selective effect on the recruitment of the dominant and solitary interestral follicles from the pool of their minor and less differentiated precursors.     

Plasma progesterone levels in sows with induced cystic ovarian follicles.

Large multiple cystic ovarian follicles were induced in three sows and small multiple cystic ovarian follicles were induced in three other sows by injections of adrenocorticotrophic hormone (ACTH) during the follicular phase of the oestrous cycle. Plasma progesterone levels in sows with large cysts were relatively high, while those of sows with small cystic follicles were low. Removal of the ovaries with large cysts from one sow resulted in a precipitous drop in progesterone levels indicating that the large cysts were primarily the source of progesterone. The method by which ACTH may induced cystic ovaries was also investigated. Plasma progesterone levels in two ovariectomised sows during ACTH treatment fluctuated markedly during a 24 h period achieving peak values of 4 or 5 ng/ml. The results suggest that progesterone of adrenal cortical origin may be a factor in the development of the cystic ovarian condition.     

Effect of a nonsteroidal aromatase inhibitor on in vitro and in vivo secretion of estradiol and on the estrous cycle in ewes.

Three experiments were performed to study effects of decreased concentrations of estradiol-17β (E₂) on lifespan and function of ensuing ovine corpora lutea (CL). In experiment 1, 52 follicles were collected from 10 ewes and placed into individual culture with 0 or .01 μCi ³H-androstenedione (10 ng; ³H-A) and 0, 10⁻¹¹, 10⁻⁹, 10⁻⁷, or 10⁻⁵ M of a nonsteroidal aromatase inhibitor, CGS16949A (CGS). Concentrations of E₂ secreted into the medium, and synthesis of estrogens as estimated by formation of ³H-water from ³H-A were decreased by 10⁻⁵ and 10⁻⁷ (P<.01), but not 10⁻⁹ or 10⁻¹¹ M CGS. In experiment 2, luteolysis was induced in 24 ewes by injection of PGF₂ on days 5 to 10 of the estrous cycle (0 hr). Ewes received 0, 0.5, 1.0, 2.0 or 4.0 mg CGS per kg BW i.v. at −12, 0, 12 and 24 hr, and an ovulatory dose of hCG at 36 hr. Jugular (P<.001) and vena caval (P<.001) concentrations of E₂ were decreased by CGS at all doses tested for 8 to 10 hr, but had returned to levels similar to control ewes by the time of the next injection. Concentrations of E₂ around the time of the LH surge were similar in control and treated ewes. During the subsequent luteal phase, concentrations of progesterone (P₄) were similar in control and treated ewes. Thus, transient decreases in E₂ during the follicular phase were not deleterious to the subsequent luteal phase. In experiment 3, luteolysis was induced in 18 ewes by injection of PGF₂ on days 6 or 7 (0 hr) of the estrous cycle. Ewes received 0 or 1 mg CGS per kg BW i.v. every 8 hr from 0 to 40 hr. Ovulation was induced with hCG at 36 hr. CGS reduced jugular (P<.001) and vena caval (P<.001) concentrations of E₂, prevented an endogenous surge of LH (P<.05) and increased (P<.001) concentrations of FSH. All ewes had ovulated a marked follicle by 72 hr, but onset of the luteal phase, as assessed by concentrations of P₄, was delayed (P<.01) in ewes receiving CGS. Delayed luteal phases were not solely attributable to the presence of new CL or to luteinization of follicular cysts. When data were aligned according to the day ewes were observed in estrus, profiles of P₄ did not differ with treatment. Therefore, normal luteal function ensued following estrus whether or not ewes re-ovulated. In conclusion, decreased secretion of E₂ by the preovulatory follicle was not involved in the ontogeny of CL of short lifespan or subnormal function. Instead, adequate production of E₂ or precisely timed E₂ secretion may be required during follicular development for subsequent functional luteinization.     

Exuberant mucometra associated with atresia of the cervix in a queen

This short communication reports the clinical, ultrasonographic and histopathological findings in a cat with atresia of the uterine cervix and mucometra. After 6 months of continuous oestrous behaviour, a remarkable abdominal enlargement was observed in a 14-year-old queen. A presumptive diagnosis of mucometra was concluded after the ultrasound evaluation and based on clinical signs and blood analyses. Ovariohysterectomy revealed a notable symmetrical distension (4-5 cm in diameter) of both uterine horns that were filled with fluid (690 ml); microbiological analyses confirmed the aseptic nature of the uterine fluid. Ovarian follicular cysts and cystic subsurface epithelial structures, >1.5 cm in diameter, were present in both ovaries and no corpora lutea were observed. Gross and microscopic evaluation of the uterus confirmed the development of cystic endometrial hyperplasia and the absence of an internal cervical os. The endometrial hyperplasia and mucometra could have developed as a consequence of repeated oestrogenic stimulation.     

QUANTITATIVE METHODS FOR INDIRECT CT LYMPHOGRAPHY

In this investigation, we applied quantitative CT methods to characterize contrast enhanced lymph nodes opacified using iodinated contrast media for indirect CT lymphography. lodinated nanoparticles were injected into the buccal submucosa and SQ into the metatarsus and metacarpus of four normal swine (1.0–4.0 ml/site, 76 mg I/ml). Attenuation (HU), volume (cm³), iodine concentration (mg I/cm³), total iodine uptake (mg I), contrast-to-noise ratio (CNR), and percent injected dose (%ID) were estimated in opacified inguinal, cervical and parotid/mandibular lymph nodes using manual image segmentation techniques on 24 hour post-contrast CT images. Lymph node volumes estimated by multiple slice ROI analysis were compared with estimates obtained by post-excisional weight measurements. HU and iodine concentration increased 5–20 fold in opacified nodes (p < 0.01) and CNR increased more than four-fold (p < 0.001). %ID ranged between 3.5 and 11.9% and did not appear dose related. ROI estimated lymph node volumes approximated volumes calculated from weight measurements. (R²= 0.94, p < 0.0001). We conclude that interstitially injected iodinated nanoparticles increase attenuation and conspicuity of targeted nodes on CT images. Quantitative methods could play an important clinical role in more accurate metastasis detection.     

Studies on Reproduction in the Goat: III. The Functional Activity of the Ovaries of the Goat

1. A study of the functional activity in the ovaries was undertaken on 366 organs from pregnant goats and 171 organs from nonpregnant goats. The ovulations were recorded by the presence of corpora lutea in the ovaries.
2. The right ovary appears to be the most active in the goat, since 57 % of the ovulations occurred in the right ovary. In cases of multiple ovulations there appears to be a greater tendency for the first of these ovulations to occur in the right ovary (62.34 %).
3. In almost 50 % of twin pregnancies both ova will be shed from the same ovary.
4. In six cases, five twin pregnancies and one triplet pregnancy, only one, respectively two corpora lutea were found. This can in all probability be taken as an indication of the occurrence of identical twins.
5. The incidence of “ovum loss” or early embryonic mortality was found to be 19.6 %.

     

Patterns of corpora lutea growth and progesterone secretion in sows with thrifty genotype and leptin resistance due to leptin receptor gene polymorphisms (Iberian pig)

The current study aimed to compare luteal function, as measured by corpora lutea dynamics and progesterone secretion, in 10 sows with obesity/leptin resistance genotype (Iberian pig) and 10 females of lean commercial crosses (Large White × Landrace). In all the animals, the oestrous cycle was synchronized with progestagens, and ovulation was induced by exogenous gonadotrophins. Thereafter, number and size of follicles and plasma oestradiol concentration were determined at oestrus detection, and number and size of corpora lutea and progesterone concentration were evaluated from Day 4 to 12 of the cycle. There were no differences between genotypes in follicle population and oestradiol concentration, and ovulation rate (15.2±1.3 in Iberian vs 12.7±1.8 in LWxL sows); however, there was a higher percentage of Iberian than control sows showing luteal cysts (66.7% vs 30%, respectively; p<0.05). In both breeds, both total luteal area and plasma progesterone concentration grew linearly from Day 4 to 8 (p<0.01) and remained more stable between Days 8 and 12, without significant differences between genotypes. In conclusion, current study supports that ovulatory processes and luteal functionality are not the main limiting factors for prolificacy in a pig model of leptin resistance and obesity.