Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study we determined whether the fetus and estrogen affect maternal serum concentrations of GH, insulin-like growth factor-II (IGF-II), and epidermal growth factor (EGF) and placental IGF-II formation in pregnant baboons. The objective was to ascertain whether the previously reported increase in placental formation and serum concentrations of IGF-I induced by removal of the fetus and, thus, estrogen in pregnant baboons was mediated by GH and whether it was specific for IGF-I. On day 100 of gestation (term is 184 days), fetuses were removed, and placentas were left in situ, i.e. fetectomy. After fetectomy, baboons received pellets of aromatizable androstenedione (50-150 mg every 10 days, sc; n = 8), were injected with estradiol (E2) benzoate (0.50-2.5 mg/day, sc; n = 8), or were not further treated (n = 6) on days 101-159 of gestation. Placental cells obtained on day 160 were dispersed in 0.1% collagenase, isolated via 50% Percoll centrifugation, then incubated for 24 h at 37 C in medium 199. Maternal serum E2 concentrations increased with advancing gestation in intact baboons, were decreased by 79% after fetectomy and, thus, removal of adrenal C-19 steroid estrogen precursors, and restored by androstenedione or E2 treatment after fetectomy. Mean serum GH was 20.2 +/- 0.6 ng/ml on days 101-160 in untreated intact animals. Fetectomy decreased (P less than 0.001) GH levels to 12.1 +/- 0.5 ng/ml. Androstenedione or E2 treatment after fetectomy restored serum GH to 20.8 +/- 1.1 and 22.4 +/- 0.6 ng/ml, respectively. Serum IGF-II was 1406 +/- 54 ng/ml on days 101-160 in controls and decreased (P less than 0.001) rapidly after fetectomy to a value (305 +/- 16) that was 78% lower than that in untreated baboons. Androstenedione or E2 treatment after fetectomy had no effect on the fetectomy-induced decrease in IGF-II levels. In vitro secretion of IGF-II by placental trophoblasts of fetectomized baboons (10.3 +/- 0.6 ng/ml.24 h) was 88% lower (P less than 0.001) than that in controls (85.6 +/- 15.7). Despite androstenedione or E2 treatment after fetectomy, placental IGF-II production remained low (9.2 +/- 1.1 and 8.8 +/- 0.4 ng/ml.24 h, respectively). The overall mean maternal serum EGF concentration was 379 +/- 20 pg/ml in the second half of baboon pregnancy. Fetectomy or treatment with androstenedione or E2 had no effect on serum EGF levels.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Influence of the fetus and estrogen on maternal serum growth hormone, insulin-like growth factor-II, and epidermal growth factor concentrations during baboon pregnancy. 195 92

We have previously shown that placental low density lipoprotein (LDL) uptake is decreased in baboons treated with antiestrogen and we have proposed, therefore, that estrogen regulates placental LDL uptake and use during primate pregnancy. In the present study, an alternate in vivo approach was employed to determine whether restoration of estrogen in animals in which the formation of estrogen was decreased would reverse the decline in LDL uptake. Placental estrogen was suppressed by removing the fetus (fetectomy) and thus adrenal androgens on day 100 of baboon gestation (term is 184 days). Placental LDL uptake was determined on day 160 after fetectomy alone, and after fetectomy and sc administration of the estrogen precursor androstenedione (50 to 150 mg every 10 days). Placental cells (10(6] were dispersed with 0.1% collagenase, isolated via 50% Percoll gradient centrifugation, then incubated at 37 C for 12 h in medium 199 with 10-100 micrograms [125I]LDL and LDL uptake (i.e. binding and internalization) determined by Scatchard analysis. In intact baboons and animals that had undergone fetectomy, syncytiotrophoblasts predominated and formed a continuous surface covering of the placental villi. Moreover, placental cells of intact and fetectomized baboons isolated on 50% Percoll consisted primarily of syncytiotrophoblasts, as evidenced by their immunohistochemical reaction with antisera against placental lactogen and pregnancy-specific-beta 1-glycoprotein. Serum estradiol in untreated baboons increased with advancing gestation and mean (+/- SE) concentrations were 1.29 +/- 0.04 ng/ml on days 101-160 of gestation. Placentas remained in situ and viable after fetectomy, but serum estradiol decreased to 0.24 +/- 0.02 ng/ml, or 19% of normal (P less than 0.01). Androstenedione restored serum estradiol after fetectomy to a mean of 0.69 +/- 0.03 ng/ml on days 101-160, or 53% of normal. Specific LDL uptake (nanograms per microgram protein) by placental cells after fetectomy alone (3.2 +/- 0.4) was 22% (P less than 0.001) of controls (14.4 +/- 1.2). Androstenedione increased (P less than 0.005) LDL uptake after fetectomy to a value (8.8 +/- 1.2) that was 61% of normal. LDL degradation, which depends on uptake, was 59 +/- 1% of normal after fetectomy and restored with androstenedione treatment to 94 +/- 2% of normal. Apparent dissociation constants (microgram/ml) for LDL uptake were similar after fetectomy (0.38), and fetectomy and androstenedione treatment (0.41), but lower (P less than 0.01) than in intact animals (0.80).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulation of placental low density lipoprotein uptake in baboons by estrogen. 198 38

In the present study, we used an in vivo approach to determine whether the fetus and estrogen have direct effects on placental production and serum concentrations of insulin-like growth factor I (IGF-I) in baboons. On day 100 of gestation, fetuses were removed and placentas left in situ (fetectomy). On days 100-155 of gestation after fetectomy, baboons received 50 mg androstenedione pellets sc in increasing numbers (1-3 every 10 days, n = 8), were injected sc with estradiol (E2) benzoate (0.50-2.5 mg/day, n = 8), or were not further treated (n = 6). Placentas were obtained on day 160, and cells were dispersed in 0.1% collagenase, isolated on 50% Percoll, then incubated for 24 h at 37 C in medium 199. Mean (+/- SE) peripheral serum E2 (nanograms per ml) in untreated baboons (n = 5) was 1.33 +/- 0.06 on days 101-160. Fetectomy decreased (P less than 0.001) E2 to 0.28 +/- 0.04, and androstenedione and E2 after fetectomy increased serum E2 to 0.75 +/- 0.08 and 2.51 +/- 0.23, respectively. Serum IGF-I (nanograms per ml) determined by RIA was 182 +/- 6 on days 101-160 in controls. Serum IGF-I increased (P less than 0.001) rapidly after fetectomy to 403 +/- 22 on days 101-160 and fell precipitously to 185 +/- 8 after placental delivery. Androstenedione and E2 treatment after fetectomy decreased IGF-I to 291 +/- 16 and 239 +/- 6, respectively, values similar to those before fetectomy. Uterine vein concentrations of IGF-I were similar to those in peripheral maternal serum, and the same relative treatment effects were observed. IGF-I secretion (picograms per ml/24 h) by placental trophoblasts of fetectomized baboons (80.1 +/- 9.8) was 242% greater (P less than 0.001) than controls (23.4 +/- 4.7) and decreased after fetectomy by androstenedione (56.7 +/- 15.1) and E2 (62.3 +/- 12.8). Thus, removal of the fetus decreased serum E2 and markedly elevated placental production and maternal serum levels of IGF-I, and these effects were largely reversed by androstenedione or E2. We suggest that the fetus, via secretion of estrogen precursors, regulates placental IGF-I production and consequently maternal serum concentrations of IGF-I during primate pregnancy.
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PMID:Influence of the fetus and estrogen on serum concentrations and placental formation of insulin-like growth factor I during baboon pregnancy. 222 24

Estrogen production in vitro was compared for Leydig cells from cryptorchid and scrotal testes in boars and stallions. Animals with natural and experimental cryptorchidism were used. Purified Leydig cells were prepared from testes of mature animals by collagenase treatment and Percoll density gradients. After incubation for 3 hours (1 X 10(6) cells), estrone sulfate and estrone in the media were measured by direct radioimmunoassay. Androstenedione and testosterone in media extracts also were determined. Cells from the abdominal testis of unilateral cryptorchid boars and stallions showed impaired estrogen production compared with that of the contralateral scrotal testis. Surgical translocation of the scrotal testis to the abdominal cavity in four unilaterally cryptorchid, prepubertal boars did not result in a reduced capacity for estrogen secretion by Leydig cells examined after puberty. Cells from the naturally retained testis in each of these four animals produced practically no estrogen. In a naturally bilateral cryptorchid stallion, there was a high rate of estrogen secretion by both testes. It was concluded that the scrotal testis of a unilaterally cryptorchid animal exerts a suppressive influence on estrogen formation by the abdominal testis.
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PMID:Impaired estrogen production by Leydig cells of the naturally retained testis in unilaterally cryptorchid boars and stallions. 287 46

The neonatal human Leydig cell undergoes a transient period of activation during the first months of life. The biological significance of this activation is unknown. Furthermore, little is known about the hormonal regulation of this biological process, even though it coincides with an elevation of LH levels in serum. In order to study the function of human prepubertal testicular culture cells, obtained during the neonatal period, a method for maintaining primary culture cells (isolated from testes collected at necropsy) in culture was developed. Within 24 h after death, testes were collected from 1-36-month-old subjects. Subjects were divided into two age groups, based on the presence or absence of fetal Leydig cells: 1-7-month-old infants (group 1) and 12-36-month-old children (group 2). Testes were digested with collagenase, and cells were seeded in multi-well dishes. Cells were grown in serum-free conditioned media supplemented with 5 mg/l vitamin C, 0.2 IU/l vitamin E and 10% fetal bovine serum for 2 days. Cells were then grown for an additional 4 days in serum-free media in the presence or absence of hLH (40 IU/l), hCG (135 IU/l), rh FSH (1.5 IU/l), rhGH (0.12 IU/l) or insulin (0.9 mumol/l). Concentrations of steroids in media were determined by RIA on day 6 of culture. In basal conditions cells of group 1 (n = 11) secreted more testosterone, androstendione, 17-hydroxyprogesterone, progesterone and dehydroepiandrosterone (mean +/- SE: 6.76 +/- 1.86, 7.37 +/- 1.82, 61.9 +/- 1.86, 5.75 +/- 1.74 and 8.51 +/- 3.23 pmol/10(6) cells/24 h, respectively) than cells of group 2 (n = 5) (2.95 +/- 1.15, 1.50 +/- 2.75, 1.44 +/- 2.75, 0.78 +/- 1.74 and 3.23 +/- 1.32, respectively). Under hLH stimulation, cells of group 1 increased testosterone, androstendione and 17-hydroxyprogesterone secretions (to 38.2 +/- 0.89, 13.5 +/- 1.17 and 51.7 +/- 3.23), while progesterone secretion remained unchanged (2.82 +/- 1.20). Cell response to rhFSH and rhGH was similar to that of hLH. On the other hand, medium collected from cultures of cells isolated from a Sertoli cell tumor was able to stimulate testosterone secretion in subcultures of control testicular cells in a way similar to that of hCG. In conclusion, (1) these prepubertal human testicular cells can be maintained in primary culture for several days keeping their in vivo steroidogenic potential; (2) cells isolated from young infants can respond to hLH in culture; (3) response to rhFSH is probably mediated by a paracrine factor; (4) response to rhGH is observed in the absence of gonadotropins.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Human prepubertal testicular cells in culture: steroidogenic capacity, paracrine and hormone control. 762 44

To determine if androstenedione, an aromatizable androgen, has a direct effect on luteal progesterone secretion, collagenase-dispersed luteal cells or whole corpora lutea from pregnant rats were incubated in the presence of the androgen. Luteal cells from 15-day pregnant rats responded to androstenedione in a dose-dependent manner, with an increase in progesterone output at doses of 1 and 10 microM, but with no effect at minor doses of the androgen. Luteal cells obtained from animals on day 4, 9, 15 or 19 of pregnancy and incubated with 10 microM of androstenedione, increased progesterone production by 243, 39, 84 and 146%, respectively. Androgens (androstenedione, testosterone or dihydrotestosterone) but no oestrogens (oestradiol or diethylstilboestrol) at a dose of 10 microM, stimulated progesterone production in incubated luteal cells obtained from 15-day pregnant rats. The time-course pattern of androstenedione-induced progesterone production was studied by superfusion experiments using corpora lutea from rats on day 15 of pregnancy. A significant progesterone output was observed when androstenedione, but not oestradiol, was perfused through the luteal tissue. Intrabursal ovarian administration of androstenedione (10 microM) to 19-day pregnant rats induced a significative increase in serum progesterone levels 8 and 24 h after treatment. These in vivo results confirm the stimulatory effect of androstendione on progesterone production obtained in incubated luteal cells from pregnant rats. This study reports a direct luteotrophic effect of androstenedione in rat corpus luteum, not mediated by previous conversion to oestrogens.
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PMID:Androstenedione stimulates progesterone production in corpora lutea of pregnant rats: an effect not mediated by oestrogen. 798 Nov 28

Leydig cells were isolated from the perch testes belonging to the pre-spawning stage by collagenase treatment and mechanical separation followed by percoll gradient. They were incubated in vitro either for 5 h or at different times in the absence (control) or presence of piscine gonadotropin (GTH, 2 microg (1 x 10(6) cells)(-1)) or 3,5,3'-triiodothyronine (T3, 50 ng (1 x 10(6) cells(-1)) or T3-induced protein (TIP, 2 microg (1 x 10(6) cells)(-1)). 3Beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3beta-HSD) activity was determined by the conversion of [3H]delta5-dehydroepiandrosterone (DHEA) to [3H]delta4-androstenedione or [3H]delta5-pregnenolone to [3H]delta4-progesterone (P4) or by spectrophotometric estimation of NADH formation from NAD. T3 significantly increased (P < 0.01) both delta5-DHEA to delta4-androstenedione and delta5-pregnenolone to delta4-P4 conversion in Leydig cells indicating stimulation of 3beta-HSD activity. T3 stimulation of 3beta-HSD activity could be inhibited by cycloheximide (50 microg ml(-1)) suggesting the involvement of T3-induced protein (TIP) which was isolated and purified earlier in this laboratory from goat Leydig cells [15]. Addition of TIP or GTH significantly stimulated Leydig cell 3beta-HSD activity (P < 0.01). However, there was a difference between TIP and GTH stimulation in time kinetic study where TIP enhanced 3beta-HSD activity at 1 h (P < 0.05), reached its peak at 3 h (P < 0.01) and then plateaued till 8 h. GTH, on the other hand, did not show any stimulation of 3beta-HSD activity for 2 h, stimulation was marked only at 3 h (P < 0.05), reached a peak at 6 h (P < 0.01) and then leveled off. Determination of Km and Vmax of the enzyme showed an increase in the velocity of reaction by GTH with unaltered Km. TIP increased both velocity and affinity of the enzyme. GTH significantly increased the synthesis of 3beta-HSD protein at 3 h (P < 0.01) reaching maximal stimulation at 6 h which clearly coincided with the enzyme activity. In contrast, TIP had no effect on 3beta-HSD protein synthesis, but its direct addition to 3beta-HSD enzyme preparation in vitro caused significant augmentation of the enzyme activity (P < 0.01) suggesting thereby its modulatory effect on the enzyme. Results, therefore, show that although both T3 and GTH stimulated perch testicular Leydig cell 3beta-HSD activity, T3 effect was not direct but mediated via TIP and there is a clear distinction between GTH and TIP stimulation. GTH increased the enzyme activity by stimulating 3beta-HSD protein synthesis while TIP acts directly on the enzyme modulating it from less active to more active state.
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PMID:Differential regulation of Leydig cell 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase activity by gonadotropin and thyroid hormone in a freshwater perch, Anabas testudineus (Bloch). 1062 32

The present study was carried out to verify that the cells attached to the outside of the basement membrane of mechanically isolated follicles are theca cells and to evaluate the effect of growth hormone (GH) on these cells. Preantral follicles, 100-140 micrometer in diameter, were mechanically isolated from 11-day-old BDF1 hybrid immature mice, divided randomly into two groups, and cultured in vitro. One group was treated with 0.1% collagenase immediately after mechanical isolation in an attempt to remove theca cells attached to the outside of the basement membrane. The other group was untreated. Morphological examination revealed that 86.1% of mechanically isolated follicles before collagenase treatment had at least one theca cell around the basement membrane on the single section. However, after collagenase treatment no theca cells remained on the basement membrane of the follicles. Androstenedione secretion as a result of stimulation by 100 ng/ml hCG was significantly higher in the culture medium of the follicles with theca cells than in those of collagenase-pretreated follicles (p < 0.0001), indicating that the cells attached to the outside of the basement membrane were actually functional theca cells, not interstitial cells. To elucidate the effect of GH on theca cells, preantral follicles cultured in the presence of 1.0 mIU/ml GH were morphologically examined. Preantral follicles mechanically isolated from immature mice showed significant proliferation of not only granulosa cells but also theca cells in the presence of GH. In particular, theca cells, which remained dotted on the basement membrane in a small number just after isolation, proliferated and finally formed complete layers after the culture with GH. This is the first report that GH induced the proliferation of theca cells to form morphologically complete layers around the preantral follicle from 11-day-old mice.
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PMID:Morphological assessment of the effect of growth hormone on preantral follicles from 11-day-old mice in an in vitro culture system. 1065 8

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