Follicle profile and plasma gonadotropin concentration in pubertal female ponies

Twelve female ponies were examined daily for 30 days and classified as ovulating (OV; N = 6; 197 ± 6 kg) or prepubertal (PP; N = 6; 196 ± 9 kg). Follicles were detected by ultrasound and gonadotropins quantified by radioimmunoassay. The mean diameter of the largest follicles was significantly larger in OV (38 ± 1 mm) than in PP (26 ± 2 mm) but there was no difference between groups in the size of the second largest follicle. There were more small follicles (<24 mm) in the PP than in the OV group, but PP fillies had a smaller number of follicles >29 mm than the OV fillies. Follicle-stimulating hormone (FSH) levels did not differ between groups but PP fillies had lower luteinizing hormone (LH) peak (8 ± 1 ng/ml) and basal (4 ± 0.5 ng/ml) levels, lower peak magnitude (2 ± 0.2 ng/ml) and period average (5 ± 0.6 ng/ml) than OV fillies (32 ± 4.5, 8 ± 1.2, 17.1 ± 6, and 15 ± 2.3 ng/ml, respectively). The PP group, in contrast to the OV group, showed no relationship between FSH surge and follicle wave emergence. We conclude that an LH concentration higher than 8 ng/ml is needed for follicle growth to a preovulatory size. Wave emergence and FSH secretion seem to be independent events, probably due to an inhibitory neural system in these PP animals. PP fillies may provide a physiological model for the study of follicle wave emergence which apparently does not depend on gonadotropin levels.

Culture of bovine ovarian follicle wall sections maintained the highly estrogenic profile under basal and chemically defined conditions

Follicle cultures reproduce in vitro the functional features observed in vivo. In a search for an ideal model, we cultured bovine antral follicle wall sections (FWS) in a serum-free defined medium (DM) known to induce 17β-estradiol (E2) production, and in a nondefined medium (NDM) containing serum. Follicles were sectioned and cultured in NDM or DM for 24 or 48 h. Morphological features were determined by light microscopy. Gene expression of steroidogenic enzymes and follicle-stimulating hormone (FSH) receptor were determined by RT-PCR; progesterone (P4) and E2 concentrations in the media were measured by radioimmunoassay. DM, but not NDM, maintained an FWS morphology in vitro that was similar to fresh tissue. DM also induced an increase in the expression of all steroidogenic enzymes, except FSH receptor, but NDM did not. In both DM and NDM, there was a gradual increase in P4 throughout the culture period; however, P4 concentration was significantly higher in NDM. In both media, E2 concentration was increased at 24 h, followed by a decrease at 48 h. The E2:P4 ratio was higher in DM than in NDM. These results suggest that DM maintains morphological structure, upregulates the expression of steroidogenic enzyme genes, and maintains steroid production with a high E2:P4 ratio in FWS cultures.

Cattle with Hair Whorl Patterns above the Eyes are More Behaviorally Agitated During Restraint

The article focuses on the temperament of cattle depending on the position of hair whorl. The article was published in the journal Applied Animal Behaviour Science.

Lock of Hair - Charles Band

Lock of hair from Charles Band – an envelope within another envelope containing Charles Band’s hair. This is from a haircut for Granny’s anniversary. The writing of the envelope says “Pussy’s hair” Nov. 21, 1922.

Four Leaf Clover & Lock of Hair

Envelope containing a four leaf clover “for luck” and little Margaret’s hair (9 mos. old), Sept. 3, 1937.

Elucidation of the biological roles of Wnt5a signaling in follicle development

La santé folliculaire est déterminée par un nombre de facteurs endocriniens, paracrines et autocrines. Les gonadotrophines hypophysaires sont les principaux moteurs du développement du follicule, mais leurs actions sont modulées localement par les hormones et des facteurs de croissance. Les glycoprotéines de la famille des WNTs représentent une grande famille de molécules impliquées dans différentes voies de signalisation. Ils sont sécrétés dans le but de moduler et coordonner la réponse des follicules aux gonadotrophines, et leurs activités sont indispensables à la fonction ovarienne et à la fertilité féminine. Les WNTs sont généralement classés en fonction de la (des) voie(s) qu’ils activent. Le rôle des membres de la voie canonique WNT et de ses composants tels que CTNNB1, WNT4, WNT2, FZD1 et FZD4 est bien établi au cours du développement du follicule chez les rongeurs. Un rôle similaire des WNTs dans les espèces mono-ovulatoires demeure essentiellement inconnu. De plus, le rôle des WNT non canoniques dans l'ovaire de rongeurs est méconnu. Les objectifs de cette thèse sont (1) d'élucider la régulation hormonale de l'expression de WNT5A et le rôle physiologique de WNT5A dans les cellules de la granulosa bovine in vitro et (2) d'identifier les rôles physiologiques de WNT5A dans l'ovaire de souris par inactivation génique conditionnelle. Chacun de ces objectifs a mené à la publication d’un article à partir des résultats obtenus au cours de cette thèse. Dans le premier article, le rôle de WNT5A dans les cellules de la granulosa bovine a été étudié in vitro. Nous avons constaté que WNT5A est un régulateur négatif de la stéroïdogenèse stimulée par la FSH issue des cellules de la granulosa, et qu'il agit en supprimant l'activité de signalisation des WNTs canoniques tout en induisant la voie de signalisation MAPK8/JUN. le deuxième article, afin d’examiner le rôle de deux WNTs non-canoniques, WNT5A et WNT11, à différents stades de développement folliculaire, nous avons généré des modèles de souris knock-out conditionnels ciblant les cellules de la granulosa pour chacun de ces WNTs. Les résultats obtenus ont permis de mettre en évidence que WNT5A est nécessaire pour assurer la fertilité normale chez la femelle, le développement folliculaire et la stéroïdogenèse ovarienne. Il est aussi un antagoniste de la réponse aux gonadotrophines, agissant par l’intermédiaire de la suppression de la signalisation canonique des WNTs. Chez les souris knock-out pour WNT11, nous ne constatons aucun défaut important dans la fertilité des femelles. L’ensemble de notre travail met en évidence que WNT5A est essentiel pour le développement normal du follicule et qu’il agit pour inhiber la différenciation des cellules de la granulosa. En résumé, nous avons fourni une étude novatrice et approfondie, utilisant plusieurs modèles et techniques pour déterminer les mécanismes par lesquels WNT5A régule le développement des follicules.

Studies on Thermodynamics and No-hair Theorem in Black hole Spacetime

Department of Physics, Cochin University of Science and Technology

Investigation of the effect of macrophages and other leukocytes on hair cell regeneration in the avian inner ear

This paper investigates the relationship between hair cell proliferation and immunosuppression in chicks.

Cisplatin ototoxicity and hair cell regeneration in the zebrafish lateral line

Hair cell death and regeneration on the zebrafish posterior lateral line was investigated after cisplatin administration. Hair cell regeneration was first observed by 24 hours of recovery and was further analyzed after specific recovery intervals. Disruption of the notch signaling pathways by the y-secretase inhibitor DAPT resulted in an increase in hair cells at three days of recovery.

Association between ovarian follicle development and pregnancy rates in dairy cows undergoing spontaneous oestrous cycles

Ovarian follicle development continues in a wave-like manner during the bovine oestrous cycle giving rise to variation in the duration of ovulatory follicle development. The objectives of the present study were to determine whether a relationship exists between the duration of ovulatory follicle development and pregnancy rates following artificial insemination (AI) in dairy cows undergoing spontaneous oestrous cycles, and to identify factors influencing follicle turnover and pregnancy rate and the relationship between these two variables. Follicle development was monitored by daily transrectal ultrasonography from 10 days after oestrus until the subsequent oestrus in 158 lactating dairy cows. The cows were artificially inseminated following the second observed oestrus and pregnancy was diagnosed 35 days later. The predominant pattern of follicle development was two follicle waves (74.7%) with three follicle waves in 22.1% of oestrous cycles and four or more follicle waves in 3.2% of oestrous cycles. The interval from ovulatory follicle emergence to oestrus (EOI) was 3 days longer (P < 0.0001) in cows with two follicle waves than in those with three waves. Ovulatory follicles from two-wave oestrous cycles grew more slowly but were approximately 2 mm larger (P < 0.0001) on the day of oestrus. Twin ovulations were observed in 14.2% of oestrous cycles and occurred more frequently (P < 0.001) in three-wave oestrous cycles; consequently EOI was shorter in cows with twin ovulations. Overall, 57.0% of the cows were diagnosed pregnant 35 days after AI. Linear logistic regression analysis revealed an inverse relationship between EOI and the proportion of cows diagnosed pregnant, among all cows (n = 158; P < 0.01) and amongst those with single ovulations (n = 145; P < 0.05). Mean EOI was approximately I day shorter (P < 0.01) in cows that became pregnant than in non-pregnant cows; however, pregnancy rates did not differ significantly among cows with different patterns of follicle development. These findings confirm and extend previous observations in pharmacologically manipulated cattle and show, for the first time, that in dairy cows undergoing spontaneous oestrous cycles, natural variation in the duration of post-emergence ovulatory follicle development has a significant effect on pregnancy rate, presumably reflecting variation in oocyte developmental competence.

Endocrine regulation of ovarian antral follicle development in cattle

Antral follicle growth in cattle occurs in two distinct phases; the first 'slow' growth phase spans the time from antrum acquisition to a size of approximately 3 mm detectable by transrectal ultrasound, and the second 'fast' phase is gondadotrophin-dependent and includes cohort growth, dominant follicle (DF) selection, and DF growth. This review summarises current concepts of the relative roles FSH and LH, ovarian and metabolic hormones play mainly in the second phase of antral follicle growth in animals of different reproductive and nutritional states. It is proposed that differential FSH response may enable one cohort follicle to become selected, and that follicular secretions, particularly inhibin, suppress FSH and thus are responsible for DF selection and dominance. Acute dependence of the DF on LH pulses will determine DF lifespan, and the LH pulse profile can be influenced by metabolic hormones such as leptin, providing one possible link for nutritional state and reproduction. Direct ovarian effects of acute and chronic changes in growth hormone, insulin and insulin-like growth factor (IGF)-I have been described on cohort follicles, DF oestrogen activity and on DF growth. Influences of metabolic hormones on early antral follicles undergoing their first 'slow' growth phase are less well described, yet metabolic hormones appear to enhance growth into the cohort available for FSH-induced emergence, and may influence subsequent developmental competence of oocytes. (C) 2003 Elsevier Science B.V. All rights reserved.

Follicle-stimulating hormone isoforms and plasma concentrations of estradiol and inhibin A in dairy cows with ovulatory and non-ovulatory follicles during the first postpartum follicle wave

Following parturition, all cows display a wave of ovarian follicular growth, but a large proportion fail to generate a preovulatory rise in estradiol, and hence fail to ovulate. Follicle-stimulating hormone (FSH) exists as multiple isoforms in the circulation depending on the type and extent of glycosylation, and this has pronounced effects on its biological properties. This study examined differences in plasma FSH, estradiol, and inhibin A concentrations, and the distribution of FSH isoforms in cows with ovulatory or atretic dominant follicles during the first postpartum follicle wave. Plasma FSH isoform distribution was examined in both groups during the period of final development of the dominant follicle by liquid phase isoelectric focusing. Cows with an ovulatory follicle had higher circulating estradiol and inhibin A concentrations, and lower plasma FSH concentrations. The distribution of FSH isoforms displayed a marked shift toward the less acidic isoforms in cows with ovulatory follicles. A higher proportion of the FSH isoforms had a pl>5.0 in cows with ovulatory follicles compared to those with atretic follicles. In addition, cows with ovulatory follicles had greater dry matter intake, superior energy balance, elevated circulating concentrations of insulin and insulin-like growth factor-I, and lower plasma nonesterified fatty acids. The shift in FSH isoforms toward a greater abundance of the less acidic isoforms appears to be a key component in determining the capability for producing a preovulatory rise in estradiol, and this shift in FSH isoforms was associated with more favorable bioenergetic and metabolic status. (C) 2008 Elsevier Inc. All rights reserved.

Bovine follicle development is associated with divergent changes in activin-A, inhibin-A and follistatin and the relative abundance of different follistatin isoforms in follicular fluid

The aim was to determine whether follicle growth in cattle is accompanied by changes in levels of inhibin-A (inh-A), activin-A (act-A) and different Mr isofomus of follistatin (FS) in bovine follicular fluid (bFF), reflecting differential roles of these proteins during folliculogenesis. Follcles (n= 146) from 2-20 min diameter were dissected from ovaries of similar to 40 cattle. Immunoassays were used to measure total FS, act-A, inh-A, oestradiol (E) and progesterone (P) levels; immunoblotting was used to quanti, the relative abundance of different FS isoforms. Follicle growth from 2-6 mm was associated with a 6-fold increase in inh-A and 30-fold increase in act-A; FS remained uniformly high from 2-10 turn. From 6-2 min, inh-A remained high while act-A and FS fell 3-fold and 2-fold, respectively. Act-A/FS ratio increased 20-fold from 2-6 mm before falling slightly through to 20 mm. Act-A/inh-A ratio increased 6-fold from 2-6 nun before falling 2-fold from 6 to 17-20 mm. These findings imply a marked increase in relative activin 'tone' around the stage at which dominant follicle,;election occurs. When larger follicles (13-20 mm) were subdivided according to E/P ratio, those with high (> 5) E/P ratio had lower (2-fold; P < 0(.)001) levels of inh-A and act-A in comparison to follicles with low (< 5) E/P ratio, but there were no significant diffierences in FS, act-A/inh-A ratio or act-A/FS ratio. Thus follicle size, but not oestrogenic status, has a major influence on the intrafollicular balance between act-A and its opposing factors, inh-A and FS. Six FS isoforms were detected in bFF (apparent Mr: 65, 41, 37, 35, 33 and 31 kDa) averaging 6, 13, 24, 26 13 and 17% respectively of total FS. During growth from 2-20 mm the proportion of total FS represented by 605, 41 and 37 kDa isoforms increased similar to 2-fold while the proportion represented by the 33 and 31 kDa isoforms decreased by 3-fold and 1(.)6-fold, respectively. Treatment of bovine granulosa cells in vitro with FSH and IGF alone or in combination increased total FS secretion up to 12-fold but did not affect the relative abundance of the five different FS isoforms detected. While the functional significance of the intriguing shift in FS isoform abundance in bFF during follicle development remains to be established, we have shown that a marked increase in intrafollicular activin 'tone' accompanies bovine follicle growth from 3-6 min, corresponding to the stage at which the FSH-dependent follicle selection mechanism operates in this species.

TGF-beta superfamily members and ovarian follicle development

In recent years, exciting progress has been made towards unravelling the complex intraovarian control mechanisms that, in concert with systemic signals, coordinate the recruitment, selection and growth of follicles from the primordial stage through to ovulation and corpus luteum formation. A plethora of growth factors, many belonging to the transforming growth factor-beta (TGF-beta) superfamily, are expressed by ovarian somatic cells and oocytes in a developmental, stage-related manner and function as intraovarian regulators of folliculogenesis. Two such factors, bone morphogenetic proteins, RMP-4 and BMP-7, are expressed by ovarian stromal cells and/or theca cells and have recently been implicated as positive regulators of the primordial-to-primary follicle transition. In contrast, evidence indicates a negative role for anti-Mullerian hormone (AMH, also known as Mullerian-inhibiting substance) of pre-granulosa/granulosa cell origin in this key event and subsequent progression to the antral stage. Two other TGF-beta superfamily members, growth and differentiation factor-9 (GDF-9) and BMP-15 (also known as GDF-9B) are expressed in an oocyte-specific manner from a very early stage and play key roles in promoting follicle growth beyond the primary stage; mice with null mutations in the gdf-9 gene or ewes with inactivating mutations in gdf-9 or bmp-15 genes are infertile with follicle development arrested at the primary stage. Studies on later stages of follicle development indicate positive roles for granulosa cell-derived activin, BMP-2, -5 and -6, theca cell-derived BMP-2, -4 and -7 and oocyte-derived BMP-6 in promoting granulosa cell proliferation, follicle survival and prevention of premature luteinization and/or atresia. Concomitantly, activin, TGF-beta and several BMPs may exert paracrine actions on theca cells to attenuate LH-dependent androgen production in small to medium-size antral follicles. Dominant follicle selection in monovular species may depend on differential FSH sensitivity amongst a growing cohort of small antral follicles. Changes in intrafollicular activins, GDF-9, AMH and several BMPs may contribute to this selection process by modulating both FSH- and IGF-dependent signalling pathways in granulosa cells. Activin may also play a positive role in oocyte maturation and acquisition of developmental competence. in addition to its endocrine role to suppress FSH secretion, increased output of inhibin by the selected dominant follicle(s) may upregulate LH-induced androgen secretion that is required to sustain a high level of oestradiol secretion during the pre-ovulatory phase. Advances in our understanding of intraovarian regulatory mechanisms should facilitate the development of new approaches for monitoring and manipulating ovarian function and improving fertility in domesticated livestock, endangered species and man.