Immunohistochemical and qPCR determination of the expression and serum level of anti-Müllerian hormone in pre-pubertal, intact and ovarian remnant syndrome detected bitches

Serum anti-Müllerian hormone is an indirect predictor of ovarian reserve in domestic cats

Anti-Müllerian hormone (AMH) serves as an indirect marker for predicting primordial follicles that are representative of ovarian reserve. In this study the possibility of using AMH and age to predict the ovarian reserve in domestic cats. Ovaries and blood were collected from 30 cats undergoing routine ovariohysterectomy. The animals were divided into three age groups: prepubertal (<4 mo, n = 10), adult (1-5 y, n = 10), and senior (>5 y, n = 10). Blood was collected at surgery for serum AMH measurements using the AMH Gen II ELISA kit. The intra-assay coefficient of variation (CV) and inter-assay CV were 3.56 % and 7.68 %, respectively. One side of the ovary was processed to determine AMH localization using immunohistochemistry and for a histological count of follicles, which is the gold standard. The expression of AMH protein was quantified from the contralateral ovary by Western blot analysis. Primordial follicles exhibited the most pronounced inverse relationship with age (rho = -0.779, P < 0.05), followed by a positive association with serum AMH concentration (rho = 0.490, P < 0.05), indicating that both age and AMH are potential markers indicative of primordial follicles. Furthermore, secondary (rho = 0.651, P < 0.05) and small antral follicles (rho = 0.648, P < 0.05) were identified as the major sources of circulating AMH, as indicated by the stronger correlation with serum AMH concentrations compared with primary follicles. However, there was no significant correlation between the expression of AMH protein and other factors, including age, primordial follicles, primary follicles, secondary follicles, small antral follicles, and serum AMH concentration. A model for predicting primordial follicle number using serum AMH concentration (AIC = 672.66, P < 0.05) and age (AIC = 668.93, P < 0.05) was established. In conclusion, both serum AMH concentration and age may serve as comparable markers of ovarian reserve in domestic cats. Moreover, AMH is particularly useful in situations where age information is not available.

Abundance of Anti-Muellerian hormone in cat ovaries and correlation of its plasma concentration with animal age, weight and stage of the estrous cycle

In female animals of different species, Anti-Müllerian hormone (AMH) is produced by follicular granulosa cells and has been associated with the ovarian follicle pool. Because concentration of AMH in plasma of ovary-intact female cats is apparently more variable than previously assumed, we have analysed AMH concentration in blood of cats (n = 93) presented for routine ovariectomy and assessed ovarian histology and AMH protein expression in the surgically removed ovaries. We hypothesised that AMH is synthesized only in preantral and small antral follicles and that plasma AMH concentration reflects the antral follicle count (AFC). Corpora lutea were detected in 35% of the female cats, whereas plasma progesterone concentration was ≥1 ng/mL in 57% of the cats. Follicular cysts were present in 15 cats (16%). Positive immunostaining for AMH protein was detected in close to all primordial and antral follicles, ovarian cysts, 70% of corpora lutea and 28% of atretic follicles. Concentration of AMH in plasma averaged 6.8 ± 0.5 ng/mL (range 1.3-21.7 ng/mL). The AFC increased with increasing AMH concentration with a moderate positive correlation between AFC and AMH (r = 0.286, p < 0.01). Plasma AMH concentration was not affected by season or cats' age, weight, stage of the estrous cycle and presence of follicular cysts. In conclusion, AMH protein is expressed in all endocrine structures of the cat ovary. While AMH is a marker for the presence of ovarian tissue, its usefulness to assess ovarian function in individual female cats is of limited value.

Serum Anti-Müllerian Hormone Levels and Estrous Monitoring of GnRH Agonist Deslorelin-Induced Estrus in Bitches: A Pilot Study

This study was performed to monitor estrous patterns and, more importantly, changes in anti-Müllerian hormone (AMH) concentrations during the peri-ovulatory period in deslorelin-induced estrous bitches. Healthy anestrous bitches (n = 4) were used. Estrus and ovulation were monitored after deslorelin implantation. Blood samples were collected for analysis of progesterone, estradiol-17ß and AMH concentrations before implantation (day 0) and on days 6, 8, 10, 12, 14, 16, 18, 20 and 22 after implantation. Six days following treatment, all bitches showed estrus signs. Ovulation took place between days 12 and 15. Circulating AMH concentrations varied among bitches from 0.12 to 3.08 ng/mL. However, no significant differences in AMH levels (mean ± SD) were observed between day 0 and days following post-implantation (p > 0.05). There were no significant correlations between AMH and estradiol or AMH and progesterone (p > 0.05). Ultrasonographically, the number of clearly identifiable ovarian follicles was higher before ovulation and the area of ovaries increased after ovulation (p < 0.05). Except for AMH, changes in vaginal cytology, estradiol-17ß and progesterone levels observed in our study were similar to naturally occurring estrus. Large intra- and inter-individual variation in AMH were observed suggesting that AMH is currently not suitable as a canine fertility marker to monitor ovarian response to deslorelin treatment for estrus induction.

Anti-Müllerian hormone concentrations in female rabbits and its relation to spay status, pseudopregnancy and ovarian follicle numbers

Anti-Müllerian hormone (AMH), known for its role during fetal sexual differentiation, is secreted by the Sertoli cells in males and the granulosa cells in females during postnatal life. As serum AMH concentrations correlate with follicle numbers, AMH is utilised as a marker of ovarian reserve in many species. In dogs and cats, AMH is used as a diagnostic tool to determine spay or neuter status. In the available literature, no research regarding serum AMH levels in rabbits has been published yet. The objectives of the present study were to 1) measure serum AMH concentrations in female rabbits and investigate the value of AMH as a diagnostic tool to differentiate between spayed and intact does, and 2) relate measured AMH levels to pseudopregnancy and ovarian follicle numbers. For AMH measurement, serum samples were obtained from sexually intact (n = 64) and spayed (n = 22) female rabbits. Spayed does were of various breeds; intact rabbits were Zika hybrid rabbits. In the intact does, AMH measurement was complemented by determination of progesterone levels, gynaecological examination, and histopathologic evaluation of the uterus and ovaries, including follicle counts. Serum AMH and progesterone concentrations were measured using a human-based chemiluminescence immunoassay (CLIA) and an enzyme-linked fluorescence assay (ELFA), respectively. Depending on progesterone levels, sexually intact does were classified into follicular (n = 52) or luteal phase (n = 12). Median serum AMH levels were 1.53 ng/ml (range 0.77 - 3.36 ng/ml) in intact and 0.06 ng/ml (range ≤ 0.01 - 0.23 ng/ml) in spayed does. AMH concentrations between the intact and spayed rabbits differed significantly and did not overlap (p < 0.001). Receiver operating characteristic (ROC) curve analysis yielded a sensitivity and specificity of 100% for a cut-off level of 0.50 ng/ml. Follicular or luteal phase had no significant influence on measured AMH levels (t = 0.061, df = 62, p = 0.951). While the number of secondary follicles correlated significantly with AMH concentrations (r_s = 0.410, p = 0.001), the number of primary or antral follicles did not (r_s = 0.241, p = 0.055 and r_s = 0.137, p = 0.281, respectively). In conclusion, a single determination of serum AMH concentrations was adequate to distinguish spayed from intact female rabbits. Among sexually intact individuals, whether does were in follicular or luteal phase had no significant influence on measured serum AMH concentrations. The relationship between small growing follicles and AMH levels as described in other species could be partially confirmed, as secondary follicles correlated significantly with AMH.

Intraovarian regulation of folliculogenesis in the dog: A review

Dog reproductive cycle is unique among other mammals in that females experience long and variable periods of ovarian inactivity. Neuroendocrine controls of the reproductive cycle have been thoroughly studied in the dog. However, there is little information regarding endocrine, paracrine and autocrine controls of dog ovarian folliculogenesis. Advancements in the understanding of mechanisms regulating dog ovarian follicle development will be helpful in the establishment of an approach to control cyclicity in this species. Furthermore, such information will likely be useful for the establishment of an in vitro follicle culture system to preserve fertility of genetically valuable disease models or endangered canids. This review highlights current knowledge on dog folliculogenesis with emphasis on endocrine, paracrine and autocrine controls of follicular development.