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 order to study the effect of cyanoketone on steroidogenesis of rat adrenal, the assay technique for corticosteroids released into the incubated media of the rat adrenal cells treated with collagenase was basically investigated. Corticosterone was measured by fluorometric method and pregnenolone by radioimmunoassay. Reliability of radioimmunoassay was satisfactory. About 400,000 cells were obtained from one adrenal gland of male or female rats and sex-dependent difference in pregnenolone and corticosterone production in response to ACTH was not found. Net corticosterone production by isolated adrenal cells was related to the log of the concentration of ACTH by a sigmoid curve over the range 1 to 1000 muU/ml. The half-maximum response was observed at an ACTH concentration of 10 muU/ml, and maximum corticosterone production responding to ACTH (100-1000 muU/ml) was about 5 mug/adrenal/120 min. When cell suspensions were incubated with 1000 muU/ml of ACTH, the conversion from pregnenolone to corticosterone was inhibited 50% by cyanoketone at a concentration of 2 times 10(-8) M. The conversion was completely inhibited at a concentration of more than 10(-7) M. Cyanoketone up to a concentration of 10(-5) M seemed to have no inhibitory effect on cholesterol side-chain cleavage. In the absence of ACTH significant amount of pregnenolone was formed (about 60 ng/adrenal) by isolated adrenal cells obtained from normal adult female rats during incubation with 10(-7) M of cyanoketone for 60 min. To eliminate the possibility of the effect of endogenous ACTH which might be present in incubation medium, cell suspensions were obtained from hypophysectomized female rats. Incubations were carried out in the same condition as mentioned above and significant amount of pregnenolone was formed by cell suspension, which was about 35 ng/adrenal.
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PMID:[Steroidogenesis in isolated adrenal cells of rat. -Effects of cyanoketone on pregnenolone and corticosterone production- (author's transl)]. 17 Jan 42

Recent data have implicated the phosphatidylinositol/calcium second-messenger system in the control of aldosterone secretion by the adrenal zona glomerulosa. However, in the rat adrenal there are few reports of a direct effect of protein kinase C activation on steroid secretion, while the effects of calcium mobilization may be variable. Since the rat adrenal zona glomerulosa is sensitive to the mode of tissue preparation, these mechanisms were reinvestigated in intact (non-dispersed) capsular tissue and collagenase-dispersed zona glomerulosa cells. Steroidogenesis in the intact zona glomerulosa was markedly affected by agonists of the calcium messenger system. Most notably, aldosterone and 18-hydroxycorticosterone (18-OH-B) secretion were stimulated by A23187 (100 nmol to 10 mumols/l) and BAY K 8644 (500 nmol/l). Phorbol 12-myristate 13-acetate (TPA; 1 pmol to 1 mumol/l) stimulated aldosterone secretion at all doses and caused a dose-dependent increase in 18-OH-B and 18-hydroxydeoxycorticosterone (18-OH-DOC) secretion. Corticosterone secretion was slightly increased in the presence of A23187 but not by TPA or BAY K 8644. Production of 18-OH-DOC was unaffected by A23187 and BAY K 8644. The calcium channel antagonist verapamil (10 mumols/l) inhibited ACTH-stimulated aldosterone secretion by the intact zona glomerulosa but had no effect on corticosterone secretion. Verapamil (10 mumols/l) also inhibited the increase in aldosterone secretion by collagenase-dispersed zona glomerulosa cells stimulated by ACTH (100 fmol to 100 nmol/l), angiotensin II (100 pmol to 10 nmol/l) and potassium (5.9 and 8.4 mmol/l); stimulated corticosterone secretion was unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Specific effects of agonists of the calcium messenger system on secretion of 'late-pathway' steroid products by intact tissue and dispersed cells of the rat adrenal zona glomerulosa. 247 55

An experimental animal model with adrenal cortex transplantation was developed to study adrenal cortex replacement therapy in patients with multiple endocrine neoplasia type 2 who have had bilateral adrenalectomy for pheochromocytomas. Adrenal cortex of syngenetic rats was isolated from the medulla by collagenase digestion and a defined sedimentation. The cell suspension of the cortical cells was implanted under the kidney capsule of untreated syngenetic rats. After two weeks the recipients were bilaterally adrenalectomized. Serum corticosterone levels were measured as an estimate of function of the grafts. All recipients were healthy throughout the observation period, whereas all adrenalectomized controls died within 18 days. Vital cortex cells could be demonstrated in the explanted grafts by immunohistochemistry. Corticosterone levels of transplanted animals were nearly normal (9.5 ng/100 mL +/- 0.4) compared to the controls (0.20 ng/mL +/- 0.06). This animal model of adrenal cortex transplantation allows the separation of medullary from cortical cells. After transplantation, these cortical cells survived for eight weeks and were able to replace the adrenal cortex function.
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PMID:Adrenal cortex transplantation after bilateral total adrenalectomy in the rat. 257 52

Isolated adrenocortical cells from White Leghorn chickens (Gallus domesticus) were compared to those from rats (Rattus norvegicus). Cells were prepared from collagenase-dispersed adrenal glands of sexually mature male animals. Corticosterone was measured by radioimmunoassay after incubation for 2 h with steroidogenic agents. Of the four ACTH analogues used, three were 6-17 times more potent with rat cells than with fowl cells (potencies were indicated by half-maximal steroidogenic concentrations). However, 9-tryptophan (O-nitrophenylsulfenyl) ACTH was 8 times more potent with fowl cells than with rat cells, thus suggesting that ACTH receptor differences exist between the two cell types. In addition, cAMP analogues were 10 times more potent with rat cells than with fowl cells suggesting that fowl corticosteroidogenesis is less dependent on cAMP than is rat corticosteroidogenesis. At equal cell concentrations, rat cells secreted 20-40 times more corticosterone than did chicken cells when they were maximally stimulated. Although rat cells converted 8 times more pregnenolone to corticosterone than did fowl cells, the half-maximal steroidogenic concentration for pregnenolone-supported corticosterone synthesis was the same for both cell types (about 5 microM). This suggests that fowl cells have lower steroidogenic enzyme content rather than lower steroidogenic enzyme activity. An unusual feature seen in the isolated fowl adrenocortical cells was an abundance of intracellular filaments.
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PMID:Isolated adrenocortical cells of the domestic fowl (Gallus domesticus): steroidogenic and ultrastructural properties. 298 70

A serum-free primary cell culture system was used to examine the direct effects and interactions of mammogenic hormones and epidermal growth factor (EGF) on the growth of mouse mammary epithelial cells. Epithelial cells were isolated by collagenase dissociation followed by Percoll gradient centrifugation and cultured within collagen gels in a mixture of Ham's F-12-Dulbecco's Minimum Essential Medium (1:1) containing insulin (10 micrograms/ml), crude soybean lecithin, trace elements, trypsin inhibitor, and antioxidants. Progesterone (P; 10(-6) - 10(-8) M) or ovine PRL (1 microgram/ml), in the absence of EGF, stimulated the growth of cells from mature virgin mice 2- to 4-fold over that of controls cultured in basal medium only. P and PRL synergized in stimulating growth 3- to 17-fold. 17 beta-Estradiol (10(-7) - 10(-10) M) alone did not stimulate growth or synergize with P and/or PRL. This lack of growth stimulation by 17 beta-estradiol was also observed in medium containing a low concentration of insulin (0.1 microgram/ml). EGF (10 ng/ml) alone stimulated growth to the same extent as the combination of P and PRL. EGF at 1, but not 10, ng/ml when combined with P and PRL could additively stimulate growth. Cells from midpregnant mice were less responsive than cells from virgin mice to the growth-stimulating effects of the combination of P and PRL (2-fold stimulation at most), but not to EGF (3- to 6-fold stimulation). Corticosterone, deoxycorticosterone, and aldosterone, but not cortisol, could synergize with PRL in stimulating the growth of cells from mature virgin mice. However, only deoxycorticosterone could stimulate growth in the absence of PRL. These results suggest that PRL, P, and adrenal corticoids may directly stimulate the growth of mouse mammary epithelial cells. The physiologically relevent adrenal corticoids, corticosterone and aldosterone, only potentiate the stimulatory effect of PRL. The hormonal stimulation of growth in vitro can be obscured by an optimum concentration (10 ng/ml) of EGF. The relative growth responses to mammogenic hormones and EGF may depend on the degree of differentiation of the cells.
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PMID:Stimulation of mammary epithelial cell growth in vitro: interaction of epidermal growth factor and mammogenic hormones. 388 12

Although the biological effects of ketanserin were originally attributed to its specific interaction with serotonin type 2 (5HT2) receptors, at high doses (greater than 10(-8)M) it also appears to act as an alpha 1-antagonist in some tissues. This in vitro study examines the possibility that Ketanserin may inhibit serotonin-induced steroidogenesis by blockade of alpha 1-receptors. Rat zona glomerulosa cells prepared by collagenase digestion of adrenal capsular tissue were incubated at 37 degrees C in Krebs-Ringer bicarbonate buffer (0.2% glucose, 0.2% bovine serum albumin) for 30 min with increasing doses of serotonin (10(-9)-10(-6)M) alone or in the presence of ketanserin (10(-6)M), methysergide (a 5HT-receptor antagonist) 10(-6)M) or prazosin (an alpha 1-antagonist)(10(-6)M). Cyclic AMP, Corticosterone and aldosterone outputs were measured by radioimmunoassay. Serotonin produced correlative sigmoidal dose responses for cyclic AMP, corticosterone and aldosterone which were inhibited by ketanserin and methysergide but not by prazosin. These results suggest that ketanserin does not act by alpha 1-blockade in the adrenal zona glomerulosa but rather as a specific 5HT-receptor antagonist.
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PMID:The specificity of ketanserin in the inhibition of serotonin-induced steroidogenesis in the rat adrenal zona glomerulosa. 610 Jul 54

Cells from adrenal glands of 140-160 days foetal, neonatal and infant Rhesus monkeys (Macaca mulatta) were prepared, by collagenase digestion and incubated with 10 pg-16 ng/ml ACTH. The production of cortisol, androstenedione, corticosterone, progesterone and prostaglandins was measured. The cortisol production in the 140 day and 160 day foetuses and in the neonatal adrenal cells was comparable. It was 2-fold higher in adrenal cells of 6 month infant monkeys. In all the groups there was an increasing production of cortisol with increasing ACTH concentration, and a response to low physiological concentrations of ACTH. The androstenedione production was significantly greater in the 160 day foetuses than in either those of 140 days or of the neonate which demonstrated a poor response to increasing ACTH concentrations. It responded well to increasing ACTH in adrenal cells from 6 month infant monkeys. Corticosterone output was 1/10th of cortisol with only the 140 day foetuses showing an increase in production with increasing ACTH concentrations. The results demonstrate that cells of the primate foetal adrenal gland are not inherently unresponsive to ACTH stimulation as regards cortisol production, which per/micrograms DNA does not appear to change over the last 25 days before term.
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PMID:ACTH control of steroid secretion from adrenal cells of the developing rhesus monkey (Macaca mulatta). 632 49

Hypoxia in vivo leads to a decrease in aldosterone not completely explained by extrinsic controllers of adrenal function including adrenocorticotrophic hormone, renin-angiotensin II, and K+. The dissociation of renin and aldosterone during acute hypoxia in vivo may be explained by the finding that aldosterone synthesis in adrenal cells is reversibly and specifically inhibited by decreases in O2 levels within the physiological range. The present study investigated whether the direct effect of acute decreases in O2 levels on aldosteronogenic pathway is altered during maturation. Adrenal cells (whole adrenals) were prepared from fetal (27 days gestation), neonatal (1 day), and infant (10 days) New Zealand White rabbits, and capsular cells were prepared from young (21 days) and adult (3 months) rabbits. All cells were dispersed with collagenase. Basal and cAMP-stimulated aldosterone production were assessed under two different levels of O2 (pO2 = 20.0 kPa or pO2 = 8.7 kPa). Decreased O2 levels significantly inhibited cAMP-stimulated aldosterone production in cells obtained from rabbits of all ages by 60 +/- 5% cAMP-stimulated aldosterone production was significantly lower in cells obtained from neonates and premature animals under both normoxic and reduced O2 conditions as compared with animals > or = 10 days old. Corticosterone production by cells obtained from adults and 21-day-old rabbits was unaffected by reduced O2 conditions suggesting a specific effect on the aldosterone pathway. The data demonstrate that the O2 sensitivity of the aldosterone pathway is present throughout development.
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PMID:Aldosterone release from adrenal cells is inhibited by reduced oxygen levels in vitro during maturation in rabbits. 898 36

Hypoxia and fluid and electrolyte disturbances are serious risks to normal postnatal development. Because a decrease in inspired O2 (hypoxic hypoxia) inhibits aldosterone synthesis in the adult and aldosterone controls water and electrolyte balance, we studied adrenocortical function in rabbits exposed to normobaric normoxia or hypoxic hypoxia (fraction of inspired O2 0.09) from birth. At 21 days of age, rabbits were anesthetized, the adrenals were rapidly removed, and the adrenal capsules containing mostly zona glomerulosa cells were separated. Cells were dispersed with collagenase and studied in vitro. Hypoxia in vivo resulted in a 73% decrease in basal aldosterone release and a 86% decrease in adenosine 3',5'-cyclic monophosphate-stimulated aldosterone release in vitro. We hypothesized that increased unesterified fatty acids could be partly responsible for inhibition of aldosterone synthesis. Total serum unesterified fatty acids in hypoxic kits were significantly increased (298 +/- 14 micromol/l) compared with normoxic kits (184 +/- 31 micromol/l). When cells from hypoxic rabbits were washed with fatty acid-free albumin and studied under conditions devoid of fatty acids, aldosterone production was partially restored. Corticosterone production was not affected by washing. Washing had no effect on aldosterone synthesis by cells from normoxic rats. Finally, exposing washed zona glomerulosa cells to oleic acid (10-50 microM) inhibited aldosteronogenesis. We conclude that exposure to hypoxia from birth attenuates aldosterone production in part due to an increase in levels of unesterified fatty acid levels.
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PMID:Effect of exposure to hypoxia from birth on aldosterone in rabbits: role of unesterified fatty acids. 914 5

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