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Biomedical subjects

T E Curry

Publications and source records attributed to T E Curry.

51 records · Page 3Linked to original sources
PubMed1988

Identification and characterization of metalloproteinase inhibitor activity in human ovarian follicular fluid.

Metalloproteinase inhibitors regulate collagenase activity in the extracellular matrix. To assess the role of metalloproteinase inhibitors in the ovulatory process, inhibitor activity was examined in human follicular fluid collected 2-4 h before ovulation. The relationship between inhibitor activity and steroid content was determined, and the inhibitors were partially purified and characterized. Inhibitory activity in follicular fluid (n = 25) correlated with both follicular estradiol (P less than 0.001) and progesterone (P less than 0.02) concentrations per follicle. Chromatographic separation of the follicular fluid on Sepharose 6B isolated two peaks of inhibitory activity. The inhibitor from the small mol wt (Mr) peak shared many of the properties of tissue inhibitors of metalloproteinase. It was stable in response to heat (60 C) and methylamine (200 mM), and was destroyed by reduction and alkylation, a procedure reported to destroy previously characterized inhibitors. Partial purification by affinity and ion exchange chromatography demonstrated the inhibitor to be a glycoprotein with an approximate Mr of 28-29K. The large Mr inhibitor had an approximate size of 700K and exhibited many of the characteristics of alpha 2-macroglobulin, a serum-derived metalloproteinase inhibitor. It was sensitive to heat, methylamine, and reduction and alkylation. Thus, follicular fluid contains metalloproteinase inhibitor activity that is steroid related and may be hormonally regulated. Ovarian metalloproteinase inhibitors may act to regulate connective tissue remodeling during follicular rupture.

Chorionic Gonadotropin↗
PubMed1988

Expression of plasminogen activator (PA) and a PA inhibitor in human granulosa cells from preovulatory follicles.

Studies with rat ovarian cells indicate that proteolytic enzymes, such as plasminogen activator (PA), play a role in the tissue remodeling that occurs before ovulation. In the rat, gonadotropins appear to increase granulosa cell tissue-type plasminogen activator (t-PA) content by increasing the cellular concentration of t-PA mRNA as well as by modulating the activity of a specific PA inhibitor (PAI). We obtained granulosa cells from preovulatory follicles of women undergoing either in vitro fertilization or gamete intra-fallopian tube transfer in order to evaluate the roles of PA and PAI in human ovulation. Samples of granulosa cell total RNA were hybridized with probes for t-PA, urokinase-type PA, PAI type 1 (PAI-1), or inhibin A-chain (as a control). Northern analyses revealed that the RNA of granulosa cells from preovulatory follicles contained little or no detectable PA mRNA. In contrast, two species of PAI mRNA were detected in relative abundance. The signal intensity produced by the PAI-1 probe varied by about 8-fold among patient samples, suggesting that PAI-1 may be useful as a marker of follicular maturation and differentiation. These results demonstrate that human granulosa cells collected immediately before ovulation contain PA inhibitor mRNA, yet have little or no PA mRNA.

Cells, Cultured↗
PubMed1987

Ovarian prostaglandin synthase: immunohistochemical localization in the rat.

Ovarian prostaglandin synthase is stimulated by the luteinizing hormone surge resulting in the preovulatory increase in prostaglandins. In the present study, the ovarian cellular localization of prostaglandin synthase was identified by immunohistochemistry. Ovaries were collected from 27-day-old rats at the time of stimulation with pregnant mare serum gonadotropin (8 IU) (zero hours), 48 hours later, or 8 hours after administration of human chorionic gonadotropin (5 IU). At zero hours prostaglandin synthase immunostaining was present in the theca of larger follicles and interstitial regions. The number and intensity of immunostained cells in the theca increased between zero and 48 hours. The granulosa cell layer adjacent to the basement membrane in large antral follicles exhibited immunostaining. A similar staining pattern was observed 8 hours after human chorionic gonadotropin. These observations indicate that in the rat, the theca, interstitium, and granulosa contain prostaglandin synthase immunoreactivity and may contribute prostaglandins during follicular development and ovulation.

Animals↗
PubMed1987

Inhibition of follicle-stimulating hormone-induced ovulation by indomethacin in the perfused rat ovary.

In isolated, perfused ovaries of rats treated with pregnant mare's serum gonadotropin (PMSG), purified preparations of ovine follicle-stimulating hormone (FSH) (oFSH-211B) and rat FSH (rFSH-I-6), 100 ng/ml, were found to induce ovulations (4.8 +/- 0.9, n = 4, and 6.4 +/- 2.0, n = 5, ovulations per ovary, respectively). Indomethacin (5 micrograms/ml) added to the perfusate inhibited this ovulatory effect and exogenous prostaglandin F2 alpha (PGF2 alpha) (1 microgram/ml), or prostaglandin E2 (PGE2) (0.5 microgram/ml), reversed the blockade. Ovine FSH and rFSH had only a weak stimulatory effect on estradiol release, and only rFSH caused a significant increase in progesterone accumulation. Indomethacin reduced the stimulatory effect of rFSH on progesterone release, and this effect was reversed by PGE2 but not by PGF2 alpha. In a 6-h incubation experiment with preovulatory rat follicles, we tested the biological activity of gonadotropins used to induce oocyte maturation. The concentration of FSH used in the perfusion experiments induced oocyte maturation in more than 88% of the oocytes studied. The data confirm earlier findings that FSH can induce ovulations and show that prostaglandins are involved in this process. The data also indicate that prostaglandins might be involved in the FSH-induced increase of progesterone levels.

Animals↗
PubMed1986

The preovulatory increase in ovarian collagenase activity in the rat is independent of prostaglandin production.

In the present study, we have examined the role of gonadotropins and prostaglandins in the preovulatory increase of ovarian collagenase activity in the rat. Whole ovaries of immature PMSG-primed rats (20 IU) were removed before and 8 h after the rats were treated with human (h) CG, Nembutal, and/or indomethacin. The ovaries were homogenized in a solution containing Triton X-100 (0.25%) and centrifuged. Collagenase was extracted by resuspending the pellets in buffer containing 100 mM CaCl2, heating to 60 C for 6 min, and centrifuging. The supernatants were treated with dithiothreitol (2 mM) and iodoacetamide (5 mM) to inactivate collagenase inhibitors. Collagenase activity was measured as the percent digestion of 3H-type I collagen/100 microliters aliquot of ovarian sample. At zero time (52 h after PMSG), ovarian collagenase activity was 4.2 +/- 1.2% digestion (mean +/- SEM, n = 3). In ovaries collected 8 h after the endogenous LH surge or 8 h after the administration of 10 IU hCG at time zero, collagenase activity rose to 19.6 +/- 2.1 (n = 6) and 22.5 +/- 1.7% digestion (n = 11), respectively. Indomethacin (1.5 mg/100 g BW) administered 30 min after hCG, produced no change in collagenase activity (24.8 +/- 2.5% digestion, n = 7) although the expected increase in ovarian prostaglandin E after hCG treatment was blocked. When the endogenous LH surge was blocked with Nembutal (3 mg/100 g BW), collagenase activity in 8-h ovaries was 6.8 +/- 1.1% digestion (n = 10). The Nembutal block of the preovulatory collagenase increase was overcome by administration of hCG (8-h ovarian enzyme activity = 22.7 +/- 3.2% digestion, n = 8). These observations demonstrate that hCG stimulates ovarian collagenase activity and that this stimulation is not dependent on prostaglandin synthesis.

Animals↗
PubMed1985

Ovarian sympathectomy in the golden hamster: effects on estrous cyclicity and follicular development.

The role of adrenergic nerves in estrous cyclicity and follicular growth was studied in sympathectomized hamster ovaries. Specific ovarian sympathectomy was accomplished by injection of 6-hydroxydopamine (6-OHDA) into the ovarian bursal sac. Ovarian sympathectomy abolished all fluorescent adrenergic nerves 4, 8 or 12 days after treatment. Bilateral ovarian sympathectomy on metestrus altered the first estrous cycle in 53% of the animals and 20% had an altered second cycle. All sham injected animals had normal cycles. Four days after sympathectomy, there was a decrease in healthy follicles 80-240 microns and 250-340 microns in diameter and increased atresia of follicles 80-240 microns and 350-440 microns in diameter compared to solvent treated ovaries. Bilateral 6-OHDA treatment did not affect ovarian weight, number of corpora lutea or the total number of follicles per ovary. These observations suggest that ovarian adrenergic nerves modulate healthy follicular development in the golden hamster.

Animals↗
PubMed1985

Ovulations in rat ovaries perfused in vitro with follicle-stimulating hormone.

Using the model of the isolated perfused rat ovary, we have found that highly purified ovine follicle-stimulating hormone (FSH) preparations cause ovulation and that this effect is not due to luteinizing hormone (LH) contamination. Ovine FSH-13 at a concentration of 1.5 mU/ml induced ovulations in all perfused ovaries (8.8 +/- 2.3 ovulations/ovary), as did a more purified preparation, ovine FSH-211B, at concentrations of 0.5 mU/ml (15.0 +/- 6.4 ovulations/ovary) and 5 mU/ml (11.3 +/- 2.6 ovulations/ovary). This ovulation-inducing effect of FSH is accompanied by a marked stimulation of estradiol levels in the perfusion medium without stimulation of progesterone levels. Furthermore, a purified rat FSH preparation (15 mU/ml) also induced ovulation in all ovaries (13.8 +/- 2.2 ovulations/ovary) as well as a stimulation of both estradiol and progesterone in the medium. These data clearly confirm the direct ovulatory effect of FSH on the ovary.

Animals↗
PubMed1985

The extraction of a tissue collagenase associated with ovulation in the rat.

A method has been developed to assay collagenase in ovarian extracts in the presence of tissue inhibitors. Rat ovarian tissue is first extracted with Triton X-100 and then heated to 60 degrees C in 50 mM Tris buffer containing 100 mM CaCl2. This extract contains collagenase activity and putative inhibitor(s). The inhibitory activity is removed by reduction with dithiothreitol and alkylation with iodoacetamide. Collagenase is then activated with aminophenylmercuric acetate and assayed using 3H-acetylated collagen from which the telopeptides have been removed. Identification of this activity as collagenase was performed by using the metalloprotease inhibitors EDTA and o-phenanthroline and by demonstration of the typical collagen cleavage fragments on sodium dodecyl sulfate-gel electrophoresis. To investigate the changes in collagenase activity associated with ovulation, immature rats received 20 IU of pregnant mare's serum gonadotropin and 52 h later 10 IU of human chorionic gonadotropin (hCG). After hCG administration, ovaries were removed at intervals from 0 to 20 h. Collagenase activity rose from 4.9 +/- 1.4% digestion of the 3H-collagen at 0 time to a maximum of 24.7 +/- 1.5% digestion at 8 h after hCG and remained high at 12 h (time of ovulation) and up to 20 h (18.7 +/- 1.9% and 16.1 +/- 1.6% digestion, respectively). These findings support a role of collagenase in the rupture of the follicle and they suggest a further role for this enzyme in the events following ovulation.

Animals↗
PubMed1984

Ovarian sympathectomy in the guinea pig. I. Effects on follicular development during the estrous cycle.

The influence of ovarian adrenergic nerves on follicular growth during the estrous cycle in the adult guinea pig was ascertained by comparing follicular development in control and chemically sympathectomized ovaries from the same animal. Selective ovarian sympathectomy was achieved by injecting 6-hydroxydopamine into a surgically closed periovarian membranous sac (bursa) on day 2 of the cycle (day 1 = day of estrus). The contralateral surgically closed ovarian bursa was injected with solvent used for 6-hydroxydopamine. Animals were laparotomized on days 5, 10 and 14 of the cycle. Blood from the utero-ovarian vein was collected bilaterally for measurement of progesterone and androstenedione. The ovaries were processed for histologic examination, and the number of follicles in each ovary was analyzed morphometrically. Sympathectomy on day 2 caused a decrease in healthy preovulatory follicles (greater than 700 micron diameter) on day 10 of the cycle. There were no differences in ovarian weights or the total number of follicles per ovary at this time. On days 5 and 14 of the cycle, there were no differences in ovarian weights, total number of follicles per ovary or follicles in any size classification. Sympathectomy did not alter progesterone levels in the utero- ovarian vein as compared to contralateral control levels. From control ovaries, there was a significant increase in progesterone in the blood of the utero-ovarian vein on day 10 but venous levels of progesterone from sympathectomized ovaries were not significantly different at any day of the cycle. In the venous effluent from sympathectomized ovaries, androstenedione was elevated at day 5 compared to days 10 and 14.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic Fibers↗
PubMed1984

Ovarian sympathectomy in the guinea pig. II. Effects on follicular development during the prepubertal period and following exogenous gonadotropin stimulation.

The role of ovarian adrenergic nerves in follicular growth was studied in prepubertal guinea pigs by determining the effect of sympathectomy on follicle populations and follicular development following exogenous gonadotropin administration. Selective unilateral ovarian sympathectomy was achieved by injecting 6-hydroxydopamine into a surgically closed periovarian bursa on day 20 postpartum. The contralateral surgically closed ovarian bursa was injected with the vehicle used for 6-hydroxydopamine. On day 25, animals were injected with pregnant mare serum or saline followed by human chorionic gonadotropin or saline 48 h later. All animals were laparotomized on day 28 and blood from utero-ovarian veins was collected bilaterally for androstenedione determination. Ovaries were processed for morphometric analysis of follicles. The sympathectomized ovary in saline-injected animals had a significant decrease in preantral follicles (characterized by less than or equal to 2 layers of granulosa cells without antrum formation), an increase in 310-500 micron diameter atretic follicles and an increase in follicles greater than or equal to 700 micron compared to the contralateral control ovary. There were no differences in androstenedione levels from the two sides, ovarian weights or the total number of follicles per ovary. Neither ovary had corpora lutea. The sympathectomized ovary in animals injected with gonadotropins was not different from the contralateral ovary in any of the parameters measured. Both control and sympathectomized ovaries had newly formed corpora lutea in response to the exogenous gonadotropins. These results suggest that ovarian adrenergic nerves normally participate in follicular development in the prepubertal guinea pig. However, exogenous gonadotropins may override neural influences on the prepubertal ovary.

Androstenedione↗
PubMed1984

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↗
PubMed1983

Ovarian blood flow in the rat: association with body weight, the estrous cycle, and pseudopregnancy.

The relationships of ovarian blood flow (OBF) to ovarian function, body weight, cyclic state, and age of the corpus luteum were studied in aging rats with acutely implanted electromagnetic blood flow probes. Ovarian function was monitored by estimation of serum 17-beta-estradiol (E2) and progesterone (P) levels during (i) different stages of body maturation as indexed by body weight, and (ii) various stages of the estrous and pseudopregnancy (PSP) cycles. A distinct elevation in basal OBF rates was observed to occur in relation to body weight/age. Basal OBF rates and body weight exhibited a near linear correlation (r = 0.985; P less than or equal to 0.001) between 200 and 260 g, with a rise in mean basal OBF rates from 1.1 to 3.2 ml/min occurring in Day-8 PSP rats (Day 0 = ovulation). In weight-regulated (greater than or equal to 250 g) cycle rats, OBF increased in parallel with serum E2 levels during the proestrus-estrus period in association with ovulation, and subsequently declined to basal levels on diestrus. In PSP rats, OBF remained elevated between Days 1 and 8, during the period of peak luteal function. Between Days 8 and 12, both OBF and luteal function declined in a parallel manner as the ovary prepared for the subsequent ovulatory period. These results indicate that during the estrous cycle, OBF rates and serum E2 levels rise in a parallel manner, whereas during PSP, serum P levels and OBF are positively correlated. The parallel decline in OBF and serum P during luteolysis suggest that both parameters are functionally related and may be regulated by either a systemic or intraovarian controlling mechanism.

Animals↗
PubMed1982

A light and electron microscopic study of the human ovarian ligament.

The structure of the human ovarian ligament was studied with light and electron microscopy, with emphasis on neural components. The ligament is primarily composed of smooth muscle arranged in an outer oblique and an inner longitudinal layer. The smooth muscle cells are connected by two types of intercellular junctional complexes, close contacts and intermediate junctions. The intercellular junctions may serve to coordinate smooth muscle activity and synchronize contractions of the ligament. Nerves are abundant and accompany the vascular supply. Specialized encapsulated neural structures previously reported were not observed. Acetylcholinesterase-positive nerves are more numerous than adrenergic nerves. Both types of nerves are associated with vascular smooth muscle. We conclude that these nerves either traverse the ligament or terminate in the ligament and are vasomotor.

Acetylcholinesterase↗
PubMedDate not supplied

Immunomodulation of rat endometriotic implant growth and protein production.

PROBLEM: The immune system has been implicated in the pathophysiology of endometriosis. To determine if modulation of the immune system influences endometriotic implant growth and protein production, the following experiment was conducted. METHOD: Female rats with surgically induced endometriosis were treated with either the immunosuppressive agent pentoxifylline (Pent; 5 mg/kg BW; N = 16) or a vehicle (N = 16) for 7 consecutive days, then killed. Twenty-four hours before death, 8 animals from each group were injected intraperitoneally with the immunostimulatory agent lipopolysaccharide (LPS; 200 micrograms/kg BW). At death, endometriotic implants were measured and protein production assessed by two-dimensional polyacrylamide gel electrophoresis. RESULT: Pentoxifylline significantly (P < 0.001) reduced endometriotic implant size (2.15 +/- 0.65 mm2 vs. 17.13 +/- 1.98 mm2) whereas LPS was without effect (18.32 +/- 2.57 mm2 vs. 17.13 +/- 1.98 mm2). Pentoxifylline also suppressed production of a portion of the proteins that comprise the implant specific group of proteins, ENDO-2, whereas LPS induced the production of two additional ENDO-2 proteins. CONCLUSION: Immunomodulatory agents can modulate rat endometriotic implant growth and production of implant-specific proteins.

Animals↗