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PubMed1999

Collagenase and gelatinase messenger ribonucleic acid expression and activity during follicular development in the rat ovary.

Metalloproteinases are members of a family of proteinases that remodel the extracellular matrix throughout the body. To test the hypothesis that metalloproteinases are regulated by gonadotropin-induced changes during follicular growth, rats were injected with eCG (20 IU, s.c.), and ovaries and serum were collected at the time of eCG administration (0 h) and at 6, 12, 24, 36, or 48 h later for analysis of metalloproteinase mRNA expression, metalloproteinase activity, and steroidogenesis. Serum estradiol levels increased from 18.9 pg/ml at 0 h to 503.8 pg/ml at 48 h. Analysis of mRNA expression was performed for collagenase-3, 72-kDa gelatinase, and 92-kDa gelatinase (n = 3-4). For collagenase-3, eCG stimulated a 32-fold increase in collagenase-3 mRNA at 48 h after eCG injection as compared to that in ovaries collected at the time of eCG administration (i.e., 0-h control). The mRNA levels for 72-kDa gelatinase were 2.8-fold compared to 0 h at 36 h after eCG treatment and returned to control levels by 48 h after gonadotropin treatment. Levels of the 92-kDa mRNA expression peaked at 24 h (4. 2-fold compared to 0 h) and returned to control levels by 36 h. Gel zymography revealed 3 gelatinolytic bands corresponding to the gelatinases of approximately 72 kDa, 92 kDa, and 105 kDa. Analysis of metalloproteinase activity as the degradation of collagen or gelatin per ovary showed an increase in gelatinolytic and collagenolytic activity between 12 and 48 h after eCG treatment. In summary, these findings demonstrate that the gonadotropin induction of folliculogenesis results in changes in the metalloproteinases that may be responsible for extracellular matrix remodeling associated with follicular growth.

Animals↗
PubMed1995

Influence of postpartum energy restriction on energy status, plasma LH and oestradiol secretion and follicular development in suckled beef cows.

Effects of postpartum energy restriction, parity and time after parturition on energy status (measured by glucose, insulin, non-esterified fatty acids (NEFAs) and beta-hydroxybutyrate), LH secretion and follicular growth were investigated in ten primiparous and nine multiparous suckled cows. Females were allocated by parity, body mass and body condition score at calving to diets supplying either 100% (CE, n = 10) or 70% (LE, n = 9) of energy requirements until day 70 postpartum. Metabolic parameters were measured every week from calving to day 70 postpartum. Blood samples were collected at intervals of 15 min for 10 h on day 30 and day 50 after parturition for LH measurement. Ovaries were examined between days 20 and 30 and days 40 and 50 postpartum by ultrasonography. Energy supply affected mean plasma concentrations of glucose (CE: 0.64 +/- 0.01 g l-1 versus LE: 0.61 +/- 0.01 g l-1; P < 0.05) and NEFA (CE: 168 +/- 17 mu eq l-1 versus LE: 309 +/- 18 mu eq l-1; P < 0.01) but by day 70 postpartum, glucose and NEFA concentrations were not significantly different between the two groups. LH pulse amplitude and frequency were not affected by energy supply (P > 0.10). However, at day 30 postpartum, LH pulse frequency was negatively correlated with plasma concentration of NEFA (r = -0.61; P < 0.01). Cows fed diets supplying 100% of energy requirements had more large follicles than did cows fed low energy diets (CE: 0.82 +/- 0.05 versus LE: 0.31 +/- 0.05; P < 0.05). The size of the largest follicle was greater in CE cows than in LE cows (CE: 10.2 +/- 0.1 mm versus LE: 8.7 +/- 0.2 mm; P < 0.05). Between 40 and 50 days postpartum, the size of the largest follicle was negatively correlated with NEFA concentration (r = -0.5; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1987

Follicular development and early luteal function of conception and non-conceptional cycles after human in-vitro fertilization: endocrine correlates.

Two-hundred patients, half of whom had on-going pregnancies, were examined in terms of follicular growth, urinary oestrogen and LH output, oocytes recovered and embryos replaced. The two groups were identical in all parameters measured except that urinary LH output was significantly higher (P less than 0.01) in non-pregnant patients on the two days prior to HCG administration. During the early to mid-luteal phase, plasma progesterone concentrations were related to the number of follicles aspirated at oocyte recovery, but the overall pattern of secretion was similar in both groups. It is concluded that monitoring urinary LH output, a non-invasive technique, may be of great value for assessing oocyte quality and predicting the outcome of in-vitro fertilization and embryo replacement.

Corpus Luteum↗
PubMed1987

Effect of estrogens on follicular development and ovarian and uterine estrogen receptors in the immature rabbit, guinea pig and mouse.

Immature rabbits, guinea pigs and mice were injected with estradiol cyclopentylpropionate (ECP) or diethylstilbestrol (DES) for 3 days to evaluate whether estrogen enhances follicular maturation. Also, estrogen receptors in the ovary and uterus from these animals were measured. Uterine weight increased in all animals treated with ECP or DES, whereas actual ovarian weight increased only in the guinea pig. This correlated with the ability of estrogens to significantly increase the number of antral follicles in the guinea pig ovary. In the rabbit and mouse, estrogen increased only the number of small or large preantral follicles. However, the number of estrogen binding sites in the ovarian cytosol and nucleus was greater in the rabbit and the mouse than in the guinea pig. The affinity of ovarian cytosol receptors was the lowest for the guinea pig among the 3 species. Thus it is seen that estrogen does not enhance follicular maturation in all animal species. The ovarian response to estrogen is not only dependent upon estrogen receptors but also unknown mechanism(s) that may be related to paracrine or autocrine functions.

Animals↗
PubMed1993

Effect of synthetic nonapeptide (Thr-Cys-Ser-Val-Ser-Glu-Trp-Gly-Ile) on ovarian follicular development in the bull frog Rana tigrina (Daud).

Effect of synthetic nonapeptide (Thr-Cys-Ser-Val-Ser-Glu-Trp-Gly-Ile) representing the amino acid sequence 86-94 of human seminal plasma was studied on the ovarian follicular growth in the bullfrog R. tigrina during preparatory phase of reproductive cycle. Daily (except on Sundays) injections of 10 micrograms nonapeptide for one month caused a significant increase in ovarian weight and number of second growth phase (SGP) or vitellogenic oocytes. The results suggest that the nonapeptide is biologically active in amphibians also.

Amino Acid Sequence↗
PubMedDate not supplied

Assessment of follicular development in clomiphene induced cycles by means of ultrasound and laparoscopy: a comparative study.

Fifty clomiphene/H.C.G. stimulated patients undergoing laparoscopy as part of their infertility work up consented to participate in a study on: the reproducibility of ultrasonic measurement of follicular size as expressed by the inter and intra observer variation; the accuracy of ultrasonic assessment of location, number and size of follicles and the growth rate of the Graafian follicle during the last 12 hr prior to oocyte collection. The inter and intra observer variation was moderate to good. Correct diagnosis of the dominant follicle was made in 73%, of the number of follicles in 72% and of follicular size (difference in size between ultrasound and laparoscopy less than 2 mm) in 48% of the material studied. There was a rather wide range in follicular growth rate values during the last 10-17 hr prior to laparoscopy.

Chorionic Gonadotropin↗
PubMed1982

[Assessment of follicular development and ovulation by ultrasound].

The relation between ultrasonographic signs of ovulation and serum estradiol (E2) rise and luteinizing hormone (LH) surge were studied. Forty-eight cycles were examined in Twenty-eight infertile patients. The correlation between the follicular diameter as measured by ultrasound and actual follicular diameter under direct visualization was also determined in 19 follicles of the 25 patients who had undergone laparotomy. In 34 of the 48 cycles, growing follicles and follicular rupture could be observed by ultrasound (72.3%). The mean diameter of the follicles measured the day before estimated ovulation was 22.4 +/- 2.75 mm(range 16-27mm). The ultrasonographic ovulation period (UOP) occurred within 24 hours from the day of maximal LH levels in 24 of the 34 cycles, and within 48 hours from the day of the E2 peak in 25 of the 34 cycles. The follicular diameter measured by ultrasound was greater than the actual diameter found during laparotomy, but there was a high degree of correlation (r = 0.900). Furthermore, the E2 and P levels in follicular fluid were high in large follicles and correlated well with the ultrasound assessments of follicular size. These results suggested that ultrasonic monitoring provides a reliable measure of follicular growth and prediction of ovulation, and offers a highly sophisticated scientific tool for the study of reproductive endocrinology.

Adult↗
PubMed1988

Sequential effects of FSH on the first stages of ovarian follicular development in normal and dwarf Snell mice.

The population of small growing ovarian follicles was divided into 4 classes according to the number of granulosa cells (from 15 to 95) surrounding the oocyte, and a comparison was made of normal and dwarf mice. Follicular cell proliferation was estimated by tritiated thymidine incorporation. In normal mice, most follicles in classes 1 (15 to 35 granulosa cells in their largest cross-section) and 2 (36 to 55 cells) were labelled (86 and 95%, respectively); FSH treatment increased the labelling index (L.I.) in all follicle classes. In dwarf mice, only 38 and 76% of follicles in classes 1 and 2, respectively, were labelled. However, FSH treatment increased the percentage of labelled follicles and the L.I. to levels which were similar to those in the ovaries of untreated, normal animals. FSH stimulation of the percentage of labelled follicles and L.I. was obvious as early as 3 h after injection. There was a major increase of the L.I. 24 h after FSH stimulation, specially in dwarf mice; several hypotheses are proposed to explain this finding. We conclude that FSH is necessary for the development of the population of small growing follicles in the mouse ovary.

Animals↗
PubMed1989

Localization of transferrin and its receptor in ovarian follicular cells: morphologic studies in relation to follicular development.

Granulosa cells perform an essential role in ovarian follicle and ovum development. Proliferating cells have an absolute requirement for iron, which is delivered by transferrin with subsequent intracellular transport via the transferrin receptor. Because iron and transferrin concentration increase in follicular fluid with advancing follicular maturation, the authors studied the distribution of transferrin and its receptor in rat and human granulosa cells with light and electron microscopic immunohistochemistry. Intense cytoplasmic staining was found in granulosa cells, with immunostaining enhancement occurring with advanced follicle maturation, including the periovulatory period. Immunoelectron microscopy showed transferrin throughout the cytoplasm, often in proximity to polyribosomes and vesicular structures. When transferrin was absent in the culture medium used to maintain granulosa cells, diminished transferrin immunostaining was seen. Based on these findings, the authors conclude that follicular maturation is closely related to high levels of cellular transferrin and transferrin receptor. Acquisition of transferrin occurs primarily by either ultrafiltration or facilitated diffusion, whereas de novo local synthesis does not have a major role.

Animals↗
PubMed1983

Follicular development during the luteal phase of the human menstrual cycle.

The aims of the present studies were to determine the number, size range, health, and steroidogenic activities of antral follicles in normal human ovaries during the luteal phase of the menstrual cycle. Steroidogenic activity was assessed from the levels of androstenedione, testosterone, and estradiol in follicular fluid and the levels of extant and FSH-stimulable aromatase activity and FSH-stimulable progestin synthesis in the granulosa cells. Data for luteal phase ovaries were compared to those obtained for ovaries from the late follicular phase. On average, 94% (range, 70-100%) of the luteal phase follicles (greater than or equal to 1 mm diameter) were atretic as assessed by oocyte viability and granulosa cell number. The largest healthy follicles during the mid- to late luteal phase were 4-4.5 mm in diameter; these contained high levels of aromatizable androgen (500-2000 ng/ml), low levels of estradiol (less than 10 ng/ml), and granulosa cells with an extant level of aromatase activity 200 times lower than that in a preovulatory follicle. Based on these biochemical criteria, healthy (luteal phase) follicles were not distinguishable from atretic follicles. Granulosa cells from the luteal phase follicles were responsive to FSH with respect to progesterone and estradiol biosynthetic activity; the aromatase system in the cells from the mid- to late luteal phase follicles was significantly more responsive to FSH than that in cells from late follicular or early luteal phase follicles (P less than 0.05). These data suggest that the number of healthy luteal phase follicles (greater than or equal to 1 mm diameter) available for subsequent preovulatory development is limited.

Adult↗
PubMed1993

Characterization of gonadotropin-releasing hormone receptors in goldfish ovary: variation during follicular development.

Gonadotropin-releasing hormone (GnRH) receptors were characterized in the goldfish ovary using an analogue of salmon GnRH ([D-Arg6,Trp7,Leu8,Pro9-NEt]GnRH; sGn-RH-A) as a labeled ligand. Binding of sGnRH-A to goldfish follicular membrane preparation was found to be saturable, reversible, and dependent on time, temperature, tissue concentration, and pH. Addition of unlabeled sGnRH-A displaced the bound 125I-labeled sGnRH-A in a dose-related manner. Hill plot as well as Scatchard analysis indicated the presence of two classes of binding sites, a high-affinity/low-capacity site and a low-affinity/high-capacity site, in the fully mature and less mature goldfish ovary. However, immature goldfish ovary contained only a single class of low-affinity binding sites. The equilibrium association constants (Ka) of the low-affinity sites were found to be similar in all follicular groups. However, there was a tendency for a higher Ka value of the high-affinity sites in the less mature follicles (0.5-0.95 mm) compared with the fully mature follicles (1.11-1.48 mm), although the differences were not statistically significant. Bound 125I-sGnRH-A was also found to be displaceable by sGnRH ([Trp7,Leu8]GnRH) and chicken GnRH-II (cGnRH-II; [His5,Trp7,Tyr8]GnRH), which occur naturally in the goldfish brain. sGnRH-A and cGnRH-II were found to bind with greater affinity than sGnRH to the goldfish ovarian GnRH binding sites.

Animals↗
PubMed2001

Ovarian follicular development following administration of progesterone or aspiration of ovarian follicles in Holstein cows.

The objective of this study was to compare the effects of administration of a single injection of progesterone (P4) and follicle aspiration on Day 7 of the estrous cycle on the timing and synchrony of follicular wave emergence, time of ovulation, and concentrations of P4, estradiol and FSH in Holstein cows. Twenty cows were assigned to 4 groups (n=5 cows per group) in a 2 by 2 factorial arrangement. Cows were treated on Day 7 (Day 0 = estrus) of the estrous cycle with either sham follicular aspiration and an oil vehicle administered intramuscularly (control), aspiration of ovarian follicles (aspiration), 200 mg of P4 im, or aspiration and 200 mg of P4 im (aspiration + P4). On Day 11, PGF(2alpha)(25mg) was administered to all groups. Synchrony of ovulation was less variable in each of the treatment groups compared with the control group (P<0.05), whereas ovulation was delayed in cows in the P4 group (P<0.05). Day of follicular wave emergence was delayed in the cows of the P4 group compared with cows in the aspiration and aspiration + P4 groups (P<0.01), whereas variability in wave emergence was less among both groups of aspirated cows compared with the cows in the control group (P<0.01). More follicles 4 to 7 mm in diameter were detected in the 2 aspiration groups compared with the cows in the control and P4 group (P<0.05). No difference was detected among groups in the maximum concentration of FSH associated with follicular wave emergence. We conclude that both the administration of P4 and the aspiration of follicles on Day 7 of the estrous cycle improves the synchrony of ovulation when luteolysis is induced on Day 11 and results in similar concentrations of FSH at the time of follicular wave emergence, but the timing of wave emergence and the number of follicles post-emergence differ.

Animals↗
PubMed2001

Ultrasonic survey of follicular development following superovulation with a single application of pFSH, eCG or hMG in goats.

During the breeding season, 42 adult German Improved Fawn nanny goats were superovulated with a single administration of pFSH, hMG or eCG at the end or a single dose of pFSH 36h before the end of estrus synchronization. Development of follicles and corpora lutea were observed by ultrasonic scanning of the ovaries every 8h from gonadotrophin treatment, until the end of estrus and once daily for the following 6 days. Differences in follicular dynamics could be realized in the four superovulation groups, and the duration of the stimulatory action following the single gonadotrophin challenge was estimated to last for 40-72h in the case of pFSH and to exceed 72h in the case of hMG and eCG treatment groups. Corpora lutea could first be detected 3 days after estrus, whereas an exact count was not possible until day 6. The ovulation rates were satisfactory, suggesting that a single injection of pFSH or hMG provides an adequate stimulus to induce a superovulatory reaction. Premature regression of corpora lutea could not be identified ultrasonographically at these early stages of the luteal phase. However, ultrasonography is a suitable method to follow follicular dynamics after superovulation and to estimate the superovulatory response in goats.

Journal Article↗
PubMed1991

Oxytocin influences preovulatory follicular development and advances ovulation in rats.

Oxytocin has been shown to advance gonadotropin secretion in pro-estrus rats. The effects that oxytocin-induced changes have on the ovary were investigated in this study. Oxytocin administered to rats at proestrus 09.00 h, 10.00 h and 11.00 h advanced follicular growth, progesterone secretion, and the time of ovulation. However, both treated and control groups of rats ovulated similar numbers of oocytes and the oocytes released were of similar fertility. Because oxytocin has been shown to induce early LH and FSH release the effects of oxytocin administration on the ovary were possibly an indirect action involving the pituitary. The results of this investigation indicate that exogenous oxytocin alters the timing but not the fertility of periovulatory events.

Animals↗
PubMed1997

Effects of dietary fat on follicular development and circulating concentrations of lipids, insulin, progesterone, estradiol-17 beta, 13,14-dihydro-15-keto-prostaglandin F(2 alpha), and growth hormone in estrous cyclic Brahman cows.

Brahman cows were used to evaluate dietary fat (3.74% [control] and 5.20% [treated]) effects on blood hormone and lipid concentrations, follicular populations, and in vitro steroidogenesis. Cows were fed and ovaries were monitored by ultrasound from d 1 of the first estrous cycle (EC) until the first follicle of the second EC reached 8 mm, at which time ovaries were harvested. Follicular fluid (FF) was collected from large- and medium-sized follicles and assayed for progesterone (P4), estradiol-17 beta (E2), testosterone, cholesterol, and triglycerides. The corpus luteum was removed, minced, treated with LH, and incubated for 4 h. Granulosa cells harvested from the largest follicle were treated with forskolin, LH, or FSH and incubated for 48 h. Blood was collected during the treatment period and plasma assayed for 13,14-dihydro-15-keto-prostaglandin F(2 alpha) (PGFM), growth hormone (GH), insulin, P4 and E2. Cholesterol and triglycerides were assayed only from blood samples collected every 7 d. Treated cows had greater (P < .01) plasma E2 during the first EC and greater (P < .01) P4 during the second EC than controls. Treated cows had elevated (P < .01) insulin following d 16 of treatment, but GH and triglycerides were similar (P > .10) in both treatment groups. Treated cows tended (P = .10) to have greater PGFM peak concentrations than controls. Plasma cholesterol was elevated (P < .01) in treated cows on d 7 of the first EC. Treated cows tended to have greater (P < .09) follicular populations during the ovulatory and first wave of the first and second EC. Treatment did not affect (P > .10) FF concentrations of P4, E2, testosterone, cholesterol, or triglyceride from either large- or medium-sized follicles. There were no differences (P > .10) in steroid hormones produced in vitro.

Animals↗
PubMed1992

Role of prostaglandin F2 alpha in follicular development and subsequent luteal life span in early postpartum beef cows.

In postpartum cows expected to have corpora lutea (CL) of normal (norgestomet-treated) compared to short (control) life spans, function of the largest follicle increases after an increase in concentrations of prostaglandin F2 alpha (PGF). To determine whether PGF alters follicular growth and subsequent life span of the CL, 43 crossbred beef cows (19 to 22 d postpartum) were assigned to one of four treatments: 1) control (C; n = 10), 2) control+PGF (CPGF; n = 10), 3) norgestomet (N; n = 13), 4) norgestomet+flunixin meglumine (NFM; n = 10). Flunixin meglumine inhibits prostaglandin endoperoxide synthase. On day 0, N and NFM cows received a 6 mg implant of norgestomet. From days 3 through 8, CPGF and NFM cows were injected every 8 hr with 10 mg PGF im or 1 g FM iv, respectively. Implants were removed on day 9. On day 11, each cow received 1000 IU of hCG im to induce formation of CL. Follicular growth was monitored by daily ultrasonography from days 6 through 11. In a majority of the cases (25/32), the largest follicle present on day 6 was still the largest on day 11; frequency of persistence did not differ with treatment. Rate of growth of the largest follicle was greater in CPGF than in N cows (.6 +/- .1 vs .3 +/- .1 mm/d, respectively; P less than .05) but did not differ between C and NFM cows (.4 +/- .1 and .5 +/- .1 mm/d, respectively). Concentrations of estradiol in NFM cows were higher (P less than .05) on day 3 and declined to concentrations similar to those of the other treatments on day 9.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗