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Follicular development, oocyte maturity and fertilization in vitro.

Forty-four infertile women in 44 cycles were stimulated by CC/hMG/hCG (39 cycles) and by CC/hCG (5 cycles) for the purpose of in vitro fertilization (IVF, 37 cases with 35 transfers) and gamete intrafallopian transfer (GIFT, 7 cases). Intraoperative ovum pick-up was performed 32-36 hours after hCG injection. Blood E2 and P levels were determined. Blood E2 was found to be proportional to the number of mature and intermediate oocytes obtained, and correlated with the number of follicles (greater than 10 mm) and the total follicular fluid volume. Altogether 213 follicles aspirated were analyzed. There was a highly significant linear correlation (r = 0.72, P less than 0.01) between the follicular diameter (X cm) on the operation day and the aspirated follicular fluid volume (FFV, Y). The equation of the line was Y = 3.8 X-4.4. The higher concentrations of follicular E2, P, FSH, LH and lower T concentration were crucial to the maturing process of oocytes. It was found that mature oocytes could be retrieved from 26.5% of the small follicles, so it is worthwhile to aspirate the small ones. The fertilization rate was much higher with the mature oocytes than the immature ones. But the morphologically mature oocytes might function differently, i.e. the mature oocytes retrieved from the small follicles or from follicles with unbalanced hormonal microenvironment usually give a low fertilization rate.

Adult↗

The role of androgens in follicular development in the ovary. I. A quantitative analysis of oocyte ovulation.

In an attempt to understand more fully processes that control the selection or recruitment of follicles for ovulation, the superovulation paradigm in combination with the androgen, 5 alpha-dihydrotestosterone, or the antiandrogens, cyproterone or cyproterone acetate, was used in the immature mouse to alter the developmental potential of follicles destined to ovulate or to become atretic. Quantitative analysis of the numbers of eggs ovulated after one or more rounds of stimulation by pregnant mare's serum gonadotrophin followed by human chorionic gonadotrophin (PMSG-hCG), revealed a dose-dependent ovulation response to exogenous androgen and antiandrogen. Low dosages of androgen improved the ovulation response significantly. Large dosages of cyproterone and cyproterone acetate (100 mg/kg body weight) generally decreased the ovulation number in gonadotrophin-injected mice, suggesting a role for androgen in preovulatory events that occur within the ripened follicle after the ovulatory stimulus (hCG) has been received. Low dosages of cyproterone, particularly 25 mg/kg, significantly enhanced the ovulatory response, a phenomenon not observed for cyproterone acetate at this dosage. Radioimmunoassays of serum LH suggested that the differential response of the ovary to the two antiandrogens was probably related to endogenous LH release. Experiments in which the time of administration of hCG +/- cyproterone was varied after PMSG priming suggested that cyproterone at a dosage of 25 mg/kg had a "rescuing" effect on follicles destined to become atretic for up to 96 hr after PMSG priming. Cyproterone at a dosage of 100 mg/kg had no such effect, and actually decreased the magnitude of the ovulatory response at all time points tested, suggesting that follicular atresia was accelerated by this treatment. Experiments in which the time of administration of cyproterone (100 mg/kg) was varied after hCG suggested that whatever the important androgen-mediated events preceding ovulation, these events occur within 2 to 3 hr after the hCG signal. By quantitating the numbers of eggs over several superovulation cycles, it could be shown that hormonal treatment in one induced cycle could affect significantly the ovulation response in subsequent cycles, suggesting that androgens influence the development of classes of follicles other than preovulatory follicles. These studies suggest that the process through which follicles are selected for ovulation is extremely sensitive to the androgenic environment and that the developmental pathways leading to ovulation or preovulatory follicular atresia are closely linked.

Animals↗

A new model for ovarian follicular development during the human menstrual cycle.

OBJECTIVE: To evaluate changes in ovarian follicle dynamics during the human menstrual cycle to test the hypothesis that folliculogenesis occurs in a wave-like fashion. DESIGN: Prospective longitudinal study. SETTING: Healthy volunteers in an academic research environment. PATIENT(S): Fifty healthy women of reproductive age (range 19-43 years) with a history of regular menstrual cycles not taking medications known to interfere with reproductive function were evaluated. INTERVENTION(S): Transvaginal ultrasonography was performed daily for one interovulatory interval (IOI). MAIN OUTCOME MEASURE(S): Changes in the diameter and number of follicles > or =5 mm were evaluated. RESULT(S): Sixty-eight percent of women exhibited two waves of follicle development during the IOI and 32% exhibited three waves. Waves were characterized by an increase and subsequent decrease in the number of follicles > or =5 mm occurring in association with the growth of > or =2 follicles to > or =6 mm. A day effect and day by wave interaction were detected in the mean diameter of the largest three follicles and the number of follicles > or =5 mm. CONCLUSION(S): The follicular wave phenomenon in women provides a new model for ovarian function during the menstrual cycle and will improve our understanding of the ovarian response to fertility and hormonal contraceptive regimens.

Adult↗

Oxytocin can affect follicular development in the adult mouse.

Injection of oxytocin into normal adult cycling mice caused alterations in ovarian histology. Oxytocin was administered early on the day of pro-oestrus and it induced the appearance of large numbers of corpora lutea by late pro-oestrus, suggesting oxytocin stimulated ovulation. When mice were examined very early on the day of normal oestrus the ovarian population of follicles was different in the experimental group from that in the control mice, there being increased numbers of preantral and antral follicles in treated animals. As oxytocin can cause an alteration in the timing of follicular maturation and ovulation processes study of communications between the adenohypophysis and areas containing oxytocin might be important for understanding physiological details of ovulation. The relative times at which, for instance, antral follicle and corpora lutea populations increased suggested that oxytocin might have more than one activity which affects ovarian behaviour.

Animals↗

Ovarian follicular development stimulated by leuprorelin acetate plus human menopausal gonadotropin in chimpanzees.

We attempted ovarian stimulation using gonadotropins in 14 chimpanzees. Subjects were given a single administration of leuprorelin acetate, followed by repeated administration of human menopausal gonadotropin (hMG) for 16-21 days. During the dosing period, the ovarian follicle diameter and count were measured by transvaginal ultrasonography. The hormone administration induced the development of multiple follicles, and multiple oocytes were subsequently retrieved. However, the follicle count was decreased, suggesting atresia, in some subjects. Statistically, the final follicle diameter was dependent on the dosing duration and the hMG dose in the late stage, while the maximum follicle count during hMG administration was dependent on age and the hMG dose in the early stage. Five subjects showed mild ovarian hyperstimulation syndrome (OHSS)-like symptoms with a high serum estradiol (E2) concentration. These results suggest that leuprorelin acetate plus hMG administration successfully stimulates the development of multiple ovarian follicles for oocyte retrieval and that the serum E2 concentration is predictive of OHSS-like symptoms in chimpanzees.

Animals↗

Effects of guanethidine administration on compensatory ovarian hypertrophy, compensatory ovulation and follicular development in the prepubertal female guinea pig.

We analyzed the participation of sympathetic ovarian innervation in the prepubertal female guinea pig on regulation of compensatory ovarian hypertrophy (COH) and compensatory ovulation at puberty. The COH of the left ovary was significantly higher that of the right one (left ovary: 41.5+/-5.2 vs. 27.5+/-5.6%, p<0.05, Kruskal-Wallis test). The sympathetic denervation induced by guanethidine administration beginnings at birth or on day 10 resulted in a significant increase of the COH by each ovary (p<0.05, Kruskal-Wallis test). Only one of the six untreated control guinea pigs sacrificed at the follicular phase ovulate. All the hemiovariectomized animals with the left ovary in situ ovulated, while only two out of five with the right ovary in situ did (100 vs. 40%: p<0.001, Kruskal-Wallis test), unlike the denervated animals, which did not ovulate. The number of corpora lutea present in the ovaries was similar among all groups of animals. These results demonstrate differences in the follicular diameter in untreated female guinea pigs and add further support to the concept of asymmetrical response of the ovaries to denervation.

Animals↗

Effect of hypothyroidism on ovarian follicular development, granulosa cell proliferation and peripheral hormone levels in the prepubertal rat.

The aim of this study was to examine the effects of prepubertal hypothyroidism on ovarian development in rats. Therefore, from birth up to day 40 postpartum, rats were given 6-propyl-2-thiouracil (PTU) via the drinking water of mothers and pups. At ages ranging from 12 to 40 days, ovarian weights were measured and serum was collected to estimate thyrotrophin (TSH), follicle-stimulating hormone (FSH) and inhibin levels. Two hours before sacrifice the animals received an injection of bromodeoxyuridine (BrdU) to estimate the proliferative activity of the follicular granulosa cells. Ovaries were fixed in Carnoy's fluid and follicle counts were performed on sections stained with anti-BrdU and with haematoxylin and eosin. The PTU treatment resulted in increased serum TSH levels, indicative of hypothyroidism, and markedly lower body and ovarian weights, whereas serum FSH and inhibin levels were hardly affected. At day 40, ovaries of PTU-treated animals contained relatively more secondary and less antral follicles, smaller non-atretic antral follicles and more atretic follicles when compared with untreated rats, while corpora lutea were absent. It is concluded that this disturbed folliculogenesis is due to inadequate thyroid hormone supply, which hampers the differentiation and not the proliferation of granulosa cells because diameters of antral follicles were significantly smaller whereas the BrdU-labelling index had not changed.

Animals↗

Ovarian morphology and follicular development in sex-linked imperfect albino (s(al)-s) and nonalbino hens before or after a forced moult.

1. The effects of the s(al-s) gene on ovarian morphology and the development of ovarian follicles in old laying hens before and after a forced moult were investigated by measuring and weighing the ovaries and follicles. 2. The laying rate of albinos was higher than that of nonalbinos before the forced moult but not afterwards. Hierarchical follicles in albino hens were smaller than those of nonalbinos before but not after the moult. 3. Growth intensity of hierarchical follicles was greater in albino hens before the moult, suggesting that follicular maturation was more rapid, possibly explaining the higher egg production observed. 4. All differences between genotypes disappeared after the moult, suggesting that the state of the ovary before a moult is independent of that afterwards.

Albinism↗

Induction of precocious puberty in heifers II: advanced ovarian follicular development.

Precocious puberty can be induced in a majority of heifers weaned early and fed a high-concentrate diet. The objective of this experiment was to determine whether induction of precocious puberty is associated with an acceleration of ovarian maturation in heifers. Crossbred Angus and Simmental heifer calves were weaned at 104 +/- 2 (n = 18; early weaned) or 208 +/- 3 (n = 10; normal-weaned, NW) d of age. The early weaned heifers were fed a high-concentrate (60% corn; EWH, n = 9) or control diet (30% corn; EWC, n = 9). The NW heifers were also fed the control diet after weaning. Daily transrectal ultrasonography was performed to characterize a complete follicular wave beginning at a mean age of 126, 161, 196, 224, and 252 (EWH and EWC), or 224 and 252 (NW) d. Blood samples were collected daily during periods of ultrasonography to determine estradiol concentrations and weekly beginning at mean ages of 153 (EWH and EWC) or 216 (NW) d to be analyzed for progesterone concentrations. Heifers in the EWH treatment were heavier (P < 0.01) than EWC heifers from a mean age of 175 d through the end of the study (treatment x age; P < 0.05). Body weights did not differ between EWC and NW. At mean ages of 196 and 224 d, the maximum diameter of the dominant follicle (MaxDF) was greater (P < 0.05) in EWH than EWC heifers. At a mean age of 224 d, MaxDF was greater (P < 0.05) in EWC than NW heifers but was not different by a mean age of 252 d. All EWH, 5 of 9 EWC, and 5 of 10 NW heifers attained puberty at less than 300 d of age (precocious puberty). Age at puberty was less (P < 0.05) in EWH (252 +/- 9 d) than in EWC and NW (308 +/- 26 and 330 +/- 25 d, respectively) treatments. Across all heifers, MaxDF and duration of follicular waves increased with age (P < 0.05), mean number of follicles during follicular waves decreased with age (P < 0.05), and peak concentrations of estradiol during follicular waves increased until a mean age of 224 d. To further characterize aspects of precocious puberty, heifers were compared across treatments between those that experienced precocious puberty and those that did not. In heifers that experienced precocious puberty, BW at puberty was less (P < 0.01) and MaxDF, follicular wave duration, and peak estradiol concentrations were greater (P < 0.05) compared with heifers that did not experience precocious puberty. Ovarian maturation was accelerated in heifers that were weaned early and fed a high-concentrate diet and was associated with precocious onset of puberty.

Aging↗

[Investigation of follicular development and oocyte maturation after cryopreservation and xenograft of newborn mouse ovaries].

In order to explore the feasibility of cryopreserving primordial follicles in attaining their developmental competence following freezing and thawing, ovaries from newborn mice were cryopreserved and the thawed ovaries were xenografted into kidney capsules of adult female mice. Ovaries were isolated from newborn B6C2F(1) female mice, infiltrated by Leibovitz 15 (L-15) medium containing 10% (V/V) fetal bovine serum (FBS) and 1.5 mol/L dimethylsulfoxide (DMSO), and then packed into 0.25 ml plastic straws. The ovaries contained in straws were frozen under nitrogen vapour at -40 degrees C in Cryocell 1200 programmable freezer, and stored in liquid nitrogen for periods ranging from 1 week to 6 months. Upon thawing, the straws were dipped into room temperature water for 10~20 s, after which the ovaries were collected and washed in L-15 buffer containing 10% (V/V) FBS without DMSO to remove cryoprotectant. The thawed ovaries were transplanted into kidney capsules of 8~12-week old adult B6C2F(1) female recipient mice by two protocols, with either 1 or 2 ovaries in each capsule. Upon withdrawal after at least 14 d of transplantation, only 45.00% (72/160) of the ovaries were recovered from 40 recipients transplanted with 2 ovaries in each capsule, compared to 82.50% (33/40) in 20 recipients with only 1 ovary in each capsule. The grafted ovaries exhibited similar follicular developmental progression to that of natural ovaries. There were antral follicles present in the transplanted ovaries on day 14, whose number increased more substantially on day 19 after transplantation. Following stimulation of the recipient mice with 10 IU PMSG on day 19 after xenografting, follicles further developed to preovulatory stage with appearance of cumulus oocytes and enlarged antrum. Oocytes from these fully grown antral follicles were collected and matured in vitro in modified essential medium-alpha (MEMalpha). After 16~17 h of culture, 40.90% of the oocytes exhibited germinal vesicle breakdown (GVBD) and among which 89.02% proceeded to the metaphase II (MII) stage as indicated by exclusion of the first polar body. The remaining oocytes were further cultured and 50.83% of which initiated GVBD by 20~21 h of culture, but only 21.40% of which proceeded to MII. The above results demonstrated that the primordial follicles in newborn mouse ovaries were capable of sustaining freezing and thawing, and reinitiating development following xenograft into kidney capsule in adult recipient female mice. Production of mature oocytes from such re-developed follicles following gonadotrophin priming and the subsequent oocyte in vitro maturation implied immense prospect of application of this method to preserve female germ cells, conserve endangered species, establish animal gene stock, and utilize oocytes in assisted reproductive techniques.

Animals↗

Diet and follicular development.

In Caucasian women, the length of the menstrual cycle is 28 days with a SD of 3.9 days. Many factors including diet modify menstrual periodicity. We have determined the effect of a meatless vegetarian diet in Caucasian women on the length of the menstrual cycle and the episodic and luteinizing releasing hormone-stimulated release of luteinizing hormone. The effect of a Western diet on the menstrual cycle in urban Black South African women was also studied. In Caucasian women, the vegetarian diet decreased (p less than or equal to 0.01) the pituitary response to luteinizing releasing hormone and decreased (p less than or equal to 0.05) the episodic release of luteinizing hormone. A Western diet increased (p less than or equal to 0.01) the duration of the follicular phase in Black South African women. Thus diet is a factor modifying the episodic release of gonadotrophins and follicular maturation.

Adult↗

Endogenous luteinizing hormone surge in women during induction of multiple follicular development with pulsatile follicle stimulating hormone.

In this study nine consecutive normally cycling women undergoing in-vitro fertilization (IVF) were superovulated with clomiphene citrate followed by pulsatile 'pure' FSH injected s.c. via a pump (28 IU every 3 h). All women displayed an endogenous LH surge, which was markedly attenuated in most of the cases (peak value 44.5 +/- 5.9 U/l, duration 29.2 +/- 1.2 h, mean +/- SEM) as compared to spontaneous cycles. An increase in serum progesterone levels before the onset of the LH surge was seen in only one woman at a time when the LH values were low. During the LH surge serum progesterone levels increased significantly in all patients (12.7 +/- 1.90 nmol/l vs 4.74 +/- 1.57 nmol/l at the onset of the surge, mean +/- SEM, P less than 0.05) indicating follicular luteinization. Very high oestradiol levels in serum were found at the onset of the LH surge (7504 +/- 898 pmol/l, mean +/- SEM). Preovulatory oocytes were recovered from all women through a laparoscope 34-36 h after the beginning of the LH surge and embryos were replaced to them after IVF. One ongoing clinical pregnancy occurred. In contrast to results in monkeys, these results demonstrate for the first time that normally cycling women superovulated with clomiphene pulsatile 'pure' FSH will display an endogenous LH surge. Although the surge is attenuated implantation can occur.

Clomiphene↗

Effects of norgestomet on follicular development in postpartum beef cows.

To examine effects of norgestomet pretreatment on development of follicles and their response to administration of gonadotropin releasing hormone (GnRH), 45 pluriparous suckled beef cows were assigned at random to receive a 6-mg implant of norgestomet for 9 d (inserted 24 d postpartum) or serve as untreated controls. Ovaries were obtained 48 h after removal of implants or 10 to 11 or 20 to 22 h after im administration of 150 micrograms GnRH at 48 h after removal of the implant. The largest follicle (F1) and all follicles within 3 mm in diameter of the F1 were dissected from the ovaries. Theca, granulosa and follicular fluid were separated and assayed for steroids and prostaglandins. Diameters and weights of F1 and weights of follicular components remained unchanged in control cows, but increased by 10 h and declined by 20 h in norgestomet-pretreated cows (treatment X time, quadratic, P less than .05). Ovarian volume and numbers of follicles at the surface of the ovary did not differ with treatment, but the diameter of the second-largest follicle (F2) was smaller (P less than .05) in norgestomet-pretreated cows than in controls (6.0 +/- .9 vs 8.2 +/- .7 mm). The F1 were embedded in the ovary in fewer norgestomet-pretreated than control cows (2/22 vs 8/23; P less than .05). Changes in steroids in F1 paralleled those in size (treatment X time, quadratic, P less than .05). Overall, F1 from norgestomet-pretreated cows had higher (P less than .05) contents of estradiol. Contents of prostaglandins in F1 follicles did not differ with treatment, but increased (P less than .05) following treatment with GnRH. The F2 had lower contents of estradiol than F1. It is suggested that norgestomet effected the maturation of a single follicle which produced more estradiol.

Anestrus↗

In vitro production of estradiol by bovine granulosa cells: evaluation of culture condition, stage of follicular development, and location of cells within follicles.

In vitro estradiol (E2) production by bovine granulosa cells was evaluated under several culture conditions, which included the presence or absence of fetal bovine serum (FBS; 2.5 and 10%), serum substitutes (1% Nutridoma [Boehringer-Mannheim, Indianapolis, IN], 2% UltroSer G [IBF Biotechnics, Villenue-la Garenne, France]), selenium (Se; 10 ng/ml), lipoprotein (0.25% Excyte/ml), O2 concentration (5 and 20%), and two attachment factors (Pronectin F and PepTite-2000). Dulbecco's Modified Eagle's medium:Ham's F-12 medium (1:1 mixture) containing 1 microM androstenedione, 1 microgram/ml insulin, and 0.1% BSA was the basal medium evaluated. The optimum conditions determined were the basal medium in 5% O2. These conditions were then used to ascertain whether or not E2 production by granulosa cells varied with respect to location of cells within a follicle. Follicular fluid was aspirated and centrifuged to obtain granulosa cells expected to be primarily luminal and cumulus cells. Follicles were then bisected, and remaining mural granulosa cells were removed by scraping the follicle wall with a fine plastic loop. Aspirated granulosa cells secreted more (p < 0.01) E2 than scraped cells. Production of E2 during Days 0 to 2 of culture by aspirated (0.15 +/- 0.05 ng/microgram DNA) and scraped (0.02 +/- 0.01 ng/microgram DNA) granulosa cells from small follicles (< 8 mm) was less than that by aspirated (6.30 +/- 2.20 ng/micrograms DNA) and scraped cells (1.90 +/- 1.00 ng/microgram DNA) from large follicles (> or = 8 mm). During Days 2 to 4 of culture when compared to Days 0 to 2, E2 production increased for aspirated (but not scraped) granulosa cells from small follicles (0.66 +/- 0.23 ng/microgram DNA)). In contrast, E2 production decreased (p < 0.05) over time in culture for aspirated (2.10 +/- 0.50 ng/microgram DNA) and scraped (0.16 +/- 0.07 ng/microgram DNA) granulosa cells from large follicles. Thus, granulosa cells proximal to the basement membrane may be less differentiated with regard to E2 production than cells distal to the basement membrane. In addition, aspirated granulosa cells from small follicles appear to continue to differentiate toward E2-producing cells during culture, a characteristic difficult to obtain with bovine granulosa cells.

Animals↗

Immunohistochemical localization of transforming growth factor-beta 1 and -beta 2 during follicular development in the adult rat ovary.

The transforming growth factors-beta (TGF-beta) affect the metabolic activities of each of the cell types in the ovary. In vitro studies using immature rat ovaries have shown the expression of TGF-beta 1 and/or TGF-beta 2 mRNA in thecal/interstitial cells and in granulosa cells (Mulheron and Schomberg, 1990; Mulheron et al., 1991). To obtain information on the localization of TGF-beta 1 and TGF-beta 2 in the rat ovary in vivo, we have examined the immunohistochemical staining using antibodies specific for either TGF-beta 1 or TGF-beta 2. In the adult ovary the immunostaining for TGF-beta 1 was intense, whereas the staining for TGF-beta 2 was faint. The pattern of immunostaining for TGF-beta 1 and TGF-beta 2 remained constant in the interstitial cell compartment and was not affected by the stage of the oestrous cycle. Since the interstitium surrounds follicles at all stages of development we conclude that TGF-beta is not actively involved in regulating the progression of follicles at discrete stages. At the time of antrum formation in the follicle, intense staining for TGF-beta 1 was observed in thecal cells. Around the preovulatory stage of development, TGF-beta 1 and TGF-beta 2 immunoreactivity was also found in the granulosa cells. In the corpus luteum, intense staining for TGF-beta 1 was found in some areas, whereas other areas were negative. Weak to moderate staining for TGF-beta 2 was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of diets containing free gossypol on follicular development, embryo recovery and corpus luteum function in Brangus heifers treated with bFSH.

Thirty 2 yr old Brangus heifers were randomly assigned to 1 of 3 dietary treatments: Control, 0 g of free gossypol (FG) per head per day (FGHD) from corn and soybean meal (SBM); 5 g of FGHD from cottonseed meal (CSM); and 15 g of FGHD from whole cottonseed (WCS). Blood samples were collected weekly for serum progesterone (P(4)) and later quantified by RIA. Whole blood was collected on Days 1, 28, 42, 56 and 70 for erythrocyte fragility (EF) analysis. Following 65 d on dietary treatments and estrus detection, the heifers received bovine-FSH (bFSH) once daily on Days 10, 11 and 12 postestrus, and PGF(2alpha) on Day 12 postestrus. Fifteen of the thirty heifers were randomly selected, and 12 h following PGF(2alpha), the ovaries were removed and follicular diameters, ovarian weight and stromal weights were recorded. Follicular fluid was analyzed for steroid content by RIA. The remaining fifteen heifers were artificially inseminated. Embryos were recovered non-surgically on Day 7 postestrus and graded, and the recovery efficiencies were calculated. Following embryo collection, both ovaries were removed, the number of CLs was recorded, and CL P(4) content was determined by RIA. By Day 42 of treatment, heifers receiving CSM had elevated (P < 0.04) EF compared with the Controls, and remained elevated above that of Controls throughout the study. At Day 70, the CSM heifers tended to have higher (P < 0.07) EF than the WCS group, which in turn tended to be higher (P < 0.06) than the Controls. The Control and CSM heifers gained weight during the 70 d treatment period, while heifers consuming WCS lost weight (P < 0.05). Ovarian and stromal weights did not differ (P > 0.10) among treatment groups. Heifers receiving CSM had fewer (P < 0.05) follicles > 5 mm than WCS or Control heifers. Follicular fluid weights and steroid content did not differ (P > 0.10) among treatments. Both CL weight and the number of CLs per heifer were similar (P > 0.10) among treatments. Heifers receiving CSM or WCS had a higher (P < 0.003) CL P(4) content per gram of CL tissue than the Controls. Progesterone content per CL was greater in WCS heifers (P < 0.003) than in CSM heifers, while both the CSM and WCS heifers had a higher CL P(4) content than the Control heifers. Weekly and Day 7 postestrus serum concentrations of P(4) were similar (P > 0.10) among treatments. The number of embryos recovered, number of degenerated embryos, embryo grades and recovery efficiencies were not affected (P > 0.10) by dietary treatments. To standardize heifers relative to the number of degenerated embryos, the percentage of degenerated embryos recovered was calculated and tended to be greater (P < 0.06) in heifers consuming CSM than in either the Control or WCS groups. While most ovarian, follicular and embryo characteristics were not affected by dietary free gossypol, these results suggest that differences in the availability of free gossypol and/or dietary components between CSM and WCS may influence weight gain, CL P(4) content and embryo viability.

Journal Article↗

Follicle-stimulating hormone-enhanced fibronectin production by chicken granulosa cells is influenced by follicular development.

Experiments were conducted in vitro to examine the effect of ovine follicle-stimulating hormone (FSH) on various fractions of fibronectin (deposited, secreted in medium, and cell-associated) resulting from culture (12 or 24 h) of chicken granulosa cells isolated from the largest (F1) and third largest (F3) preovulatory follicles as well as from a pool of immature small yellow follicles (SYF). Fibronectin in each fraction was quantified with a specific ELISA. The amount of fibronectin deposited in culture wells containing unstimulated cells increased with time and was greatest in wells containing F1 cells. Follicle-stimulating hormone increased the quantity of fibronectin deposited within 12 h by F3 and SYF cells, but not by F1 cells. The magnitude of FSH-enhanced fibronectin deposition was greatest in cells derived from immature SYF. Fibronectin secreted in the medium by unstimulated cells also increased with the stage of follicular maturation. Follicle-stimulating hormone increased the amount of fibronectin secreted in the medium by F3 and SYF cells. The quantity of fibronectin associated with cells was increased by FSH in all cell types. Total (deposited plus medium plus cell-associated) fibronectin production was elevated in a dose- and time-dependent manner when FSH was added to F3 and SYF granulosa cells, but the gonadotropin was without effect in F1 cells. The magnitude of FSH stimulation (fold increase) of total fibronectin production was calculated as a multiple of the unstimulated (control) value for each cell type. The relative change in total fibronectin production resulting from addition of FSH (after 24 h incubation) was .02- to .24-fold in F1 cells as compared with .33- to .92-fold in F3 cells and 2.75- to 4.38-fold in SYF cells. These results indicate that FSH stimulates fibronectin production by chicken granulosa cells, and this stimulatory effect decreases as the follicle matures.

Animals↗

Effect of ovarian sympathectomy on follicular development during compensatory ovarian hypertrophy in the guinea-pig.

Selective ovarian sympathectomy was achieved by injecting 6-hydroxydopamine into a surgically closed periovarian bursa on Day 3 of the oestrous cycle (Day 1 = day of oestrus). Control ovaries had the periovarian bursa surgically closed and were injected with solvent. On Day 15 of the cycle, serum was collected for progesterone determination and ovaries were processed for morphometric analysis of follicles. In both control and sympathectomized ovaries remaining after unilateral ovariectomy on Day 3, there was an increase in ovarian weight and an increase in healthy preovulatory follicles (greater than 700 microns diam.). Sympathectomy of the ovary remaining after unilateral ovariectomy increased healthy follicles 510-700 microns diameter but decreased the total number of follicles per ovary. In animals bearing both ovaries, unilateral sympathectomy did not affect any of the characteristics measured. Serum progesterone concentrations were unaffected by any of the treatments. These results indicate that adrenergic nerves play a role in follicular dynamics in ovaries undergoing compensatory hypertrophy but are not necessary for compensatory increases in weight and number of preovulatory follicles.

Animals↗