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S M Laird

Publications and source records attributed to S M Laird.

At least 37 records · Page 2Linked to original sources
PubMed1998

Serum androgen levels in women who have recurrent miscarriages and their correlation with markers of endometrial function.

OBJECTIVE: To compare plasma androgen concentrations in women who have recurrent miscarriages and in fertile women, and to correlate the results with concentrations of the endometrial protein PP14 in uterine flushings and plasma from women who have recurrent miscarriages. DESIGN: Retrospective study. SETTING: Hospital research unit. PATIENT(S): Women attending a recurrent miscarriage clinic and normal fertile volunteers. Ten of the women with recurrent miscarriages had polycystic ovary disease (PCOD) as assessed by ultrasonography or increased follicular LH levels. INTERVENTION(S): Plasma samples were obtained from the women on days LH-7, LH-4, LH+0, and LH+7 or LH+10 of a cycle. An endometrial flushing sample and a biopsy specimen were taken from women with recurrent miscarriages on day LH+7 or LH+10. MAIN OUTCOME MEASURE(S): Androstenedione, testosterone, and sex hormone-binding globulin (SHBG) were measured in the plasma samples. The endometrial protein PP14 was measured in the uterine flushings and in the LH+7 or LH+10 plasma samples from the women with recurrent miscarriages. RESULT(S): Testosterone concentrations were higher in the women with recurrent miscarriages both with and without PCOD on days LH-7 and LH-4 of the cycle. Concentrations of androstenedione also were higher in the women with recurrent miscarriages, but without PCOD on day LH-7. Testosterone SHBG ratios were higher in the women with recurrent miscarriages, without PCOD compared with the controls on days LH-7, LH+0, and LH+7. Mean follicular testosterone concentrations were correlated negatively with both uterine (r = -0.47) and plasma (r = -0.49) PP14 levels on day LH+10. Mean luteal phase testosterone SHBG ratios were correlated negatively with uterine PP14 concentrations on day LH+7 of the cycle (r = -0.674). CONCLUSION(S): Androgen levels are higher in women who have recurrent miscarriages than in normal fertile controls. These high levels of androgens may have a detrimental effect on endometrial function.

Abortion, Habitual↗
PubMed1998

Tumour necrosis factor stimulates stress-activated protein kinases and the inhibition of DNA synthesis in cultures of bovine aortic endothelial cells.

In this study, we examined the ability of tumour necrosis factor-alpha (TNF) to stimulate the mitogen-activated protein (MAP) kinase homologues p42/44 MAP kinase, c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase and its effect upon DNA synthesis in primary cultures of bovine aortic endothelial cells (BAECs). TNF strongly stimulated p38 MAP kinase and JNK activity in both a time- and concentration-dependent manner. By contrast, TNF was a very poor activator of p42/44 MAP kinase relative to the known activator of p42/44 MAP kinase in endothelial cells, adenosine triphosphate (ATP). TNF-stimulated activation of p38 MAP kinase, and MAPKAP kinase-2, a known downstream target of p38 MAP kinase, was strongly inhibited by pre-incubation with the p38 MAP kinase inhibitor SB203580, whereas the minor activation of p42/44 MAP kinase was abolished by pre-incubation of the cell with the novel MAP kinase kinase 1 inhibitor PD098059. Addition of TNF resulted in a 50-60% decrease in DNA synthesis in BAECs. Pre-incubation with PD098059 or co-incubation with ATP failed to modify the inhibitory effect of TNF upon DNA synthesis. SB203580 reduced basal DNA synthesis by approximately 50%; however, if failed to modify the inhibition mediated by TNF. These results indicate that TNF strongly activates both p38 MAP kinase, JNK and, to a minor extent, p42/p44 MAP kinase. It is likely that only one of these kinases, JNK, plays a role in the regulation of DNA synthesis in these cells.

Animals↗
PubMed1998

Is the measurement of placental protein-14 and CA-125 in plasma and uterine flushings useful in the evaluation of peri-menopausal and post-menopausal bleeding?

In this prospective study, we examined the possible diagnostic value of the measurement of two endometrial proteins, placental protein-14 (PP14) and CA-125, in the evaluation of pre- and post-menopausal bleeding. Concentrations of these two proteins were measured in plasma and uterine flushings obtained from 139 pre- and post-menopausal women with bleeding problems, and 26 normal post-menopausal control women without bleeding. Endometrial biopsy samples were also obtained for histological study. Concentrations of PP14 in both the plasma and uterine flushings in post-menopausal women were significantly lower (P < 0.001) than those of control pre-menopausal women. In post-menopausal women, the concentrations of PP14 (mean +/- SEM) in both plasma and flushing were significantly higher (P < 0.001) in women with endometrial adenocarcinoma (46.9+/-7.5 ng/ml plasma; 3350+/-1711 ng/ml flushing) than in the controls (7.6+/-1.3 ng/ml plasma; 125+/-27 ng/ml flushing) or in women with post-menopausal bleeding and atrophic endometrium (20.4+/-2.1 ng/ml plasma; 453+/-167 ng/ml flushing). In contrast CA-125 concentrations in plasma and flushings were similar in post-menopausal and pre-menopausal women. Plasma concentrations of CA-125 were higher in post-menopausal women with adenocarcinoma (29.1+/-7.4 IU/ml) than in those with post-menopausal bleeding and atrophic endometrium (21.8+/-2 IU/ml) (P < 0.05) or control post-menopausal subjects (16.1+/-2.1 IU/ml) (P < 0.01). CA-125 concentrations in uterine flushings were not significantly different in any group of post-menopausal women. The results show that concentrations of PP14 are correlated more strongly to endometrial histopathology than those of CA-125 in pre- and post-menopausal women. Elevated PP14 concentrations are also associated with the presence of endometrial adenocarcinoma and may have a potential to be used as a marker for this disease.

Adenocarcinoma↗
PubMed1998

Endometrial protein PP14 and CA-125 in recurrent miscarriage patients; correlation with pregnancy outcome.

The concentrations of endometrial proteins PP14 and CA-125 were measured in uterine flushings taken on days LH+10 and LH+12 (10 and 12 days after luteinizing hormone surge) of the menstrual cycle from 15 normal, fertile women and 49 women who suffered recurrent miscarriage. The concentration of PP14 was significantly lower in the flushings from the recurrent miscarriage patients than in those from fertile controls on both day LH+10 (median: 1300, range: 3-10 300 ng/ml versus median: 13 933, range: 2174-40 404 ng/ml; P < 0.01) and LH+12 (median: 1560, range: 820-12 100 ng/ml versus median: 14 047, range 1402-62 108 ng/ml; P < 0.05). Similarly concentrations of CA-125 were significantly lower in flushings from recurrent miscarriage women compared to controls on both day LH + 10 (median: 1555, range: 47-6710 U/ml versus median: 6385.5, range 2884-27 731 U/ml, P < 0.01) and LH+12 (median: 2892, range: 956-9974 U/ml versus median: 7127.5, range: 1591-21 343 U/ml; P < 0.05). In contrast there was no significant difference in the concentration of PP14 in plasma samples taken on the same days as the flushings from recurrent miscarriage patients and fertile controls. The concentrations of PP14 in uterine flushings obtained on day LH + 10 or LH + 12 from recurrent miscarriage women during a pre-pregnancy investigative cycle were significantly lower (P < 0.05) in patients who went on to miscarry (median: 1000, range: 9-2900 ng/ml) than those who went on to have a live birth (median: 1440, range: 4-12 100 ng/ml) during a subsequent pregnancy. In contrast there was no significant difference in uterine CA-125 or plasma PP14 concentrations between these two groups of recurrent miscarriage patients. The results suggest that measurements of uterine PP14 and CA-125 may be useful in the assessment of endometrial development in recurrent miscarriage patients and suggest the importance of PP14 in preparing the endometrium for embryo implantation. In addition pre-pregnancy uterine PP14 measurements may be useful in predicting subsequent pregnancy outcome.

Abortion, Habitual↗
PubMed1998

The value of biochemical and ultrasound measurements in predicting pregnancy outcome in women with a history of recurrent miscarriage.

In this study, the potential prognostic value of serial ultrasonographic, endocrinological and biochemical measurements in the early pregnancy of women with a history of unexplained recurrent miscarriage was examined. A total of 113 pregnancies among 93 women were studied, of which 77 (68%) resulted in live birth, whereas 36 (32%) ended in a miscarriage. The normal range (5-95th centile) of various measurements was derived from pregnancies which resulted in a live birth. Among the 36 failed pregnancies, 42% had one or more human chorionic gonadotrophin (HCG) measurements, 35% had one or more gestation-sac diameter measurements, 33% had one or more embryonic heart rate measurements, 20% had one or more crown-rump length measurements and 9% had one or more placental protein 14 measurements below the normal range, a week or more prior to the confirmation of miscarriage. Altogether, 22/36 = 61% of the failed pregnancies could have been predicted on the basis of one or more of the measurements below the normal range.

Abortion, Habitual↗
PubMed1998

A prospective randomized controlled study comparing the morphological and biochemical responses of the endometrium to two different forms of 'period-free' hormone replacement therapy.

Thirty postmenopausal women were randomized to receive either continuous combined (cc) 2 mg oestradiol valerate and 0.7 mg norethisterone acetate hormone replacement therapy (HRT) daily (15 women) or tibolone 2.5 mg daily (15 women) and were monitored to determine the relationship between the two biochemical markers placental protein 14 (PP14) and the glycoprotein CA125, endometrial histology and occurrence of irregular bleeding after 12 months of treatment. The concentrations of PP14 and CA125 in plasma and uterine flushings before and after therapy were measured and their concentrations were associated with the histology of endometrial biopsies obtained on the same day as venesection and endometrial flushing. The levels of PP14 in uterine flushings were significantly increased after the administration of both types of HRT (P < 0.05 for tibolone and P < 0.001 for ccHRT). However, the concentrations of PP14 found in flushings after ccHRT were considerably greater than those found in flushings after tibolone; levels were increased about 150-fold by ccHRT and 6-fold by tibolone (P < 0.001). Plasma concentration of PP14 after both types of HRT were also significantly raised to a similar degree (P < 0.01). In contrast, the concentration of plasma and uterine CA125 were unchanged by either treatment. Histological analysis of the endometrium from women after 12 months of HRT treatment showed that 86% (6/7) of women on ccHRT had secretory activity as compared to 44% (4/9) women on tibolone (P < 0.05). Women with higher post-HRT uterine PP14 concentration were more likely to have irregular bleeding (P < 0.05). Our studies have shown that endometrial PP14 but not CA125 concentrations are raised to a significant degree by two different forms of period-free HRT regimens. Increased PP14 concentrations in uterine flushing may suggest endometrial stimulation of some form and predict the predilection to irregular bleeding. Thus uterine PP14 concentrations may be used to monitor endometrial responses in women on HRT.

CA-125 Antigen↗
PubMed1997

The production of leukaemia inhibitory factor by human endometrium: presence in uterine flushings and production by cells in culture.

The concentration of leukaemia inhibitory factor (LIF) was measured in uterine flushings obtained from normal fertile women, from women with unexplained infertility and from women who suffered recurrent miscarriage. In normal fertile women, LIF was not detected in flushings obtained on days luteinizing hormone (LH)+0 to LH+6 of the cycle, but concentrations gradually increased from day LH+7 to a maximum at day LH+12. The amount of LIF in flushings obtained from women with unexplained infertility was significantly lower than in those from normal fertile women on day LH+10 (P < 0.05). The production of LIF by cultured human epithelial and stromal cells was also investigated. LIF was not detectable in the supernatants of cultured stromal cells. Basal LIF production by epithelial cells varied according to the stage in the cycle at which the biopsy was taken. Significantly more LIF was produced by epithelial cells from late proliferative and early secretory endometrium compared with amounts produced by cells from early proliferative (P < 0.001) and late secretory (P < 0.01) endometrium. High doses of progesterone and oestradiol caused a small decrease in epithelial cell LIF production: the combined effect of progesterone and oestradiol (P < 0.01) was greater than the effect of either steroid alone (P < 0.05). The results show, for the first time, the capability of human endometrium to produce LIF in vivo. The fact that maximum LIF concentrations are present at implantation and that decreased concentrations occur in women with unexplained infertility suggest the importance of this cytokine in embryo implantation.

Cells, Cultured↗
PubMed1997

Stability of serum interleukin-10 levels during the menstrual cycle.

PROBLEM: Menstrual cycle-associated variability in the circulating levels of several cytokines can be a confounding factor in measurements of in vivo cytokine levels in clinical studies. Since pregnancy-associated increases in interleukin-10 (IL-10) levels are well documented, we have investigated the variability in serum levels of IL-10 in healthy women at different stages of the menstrual cycle to ascertain whether this is a problem in comparative studies of circulating IL-10 levels. METHOD OF STUDY: We obtained fifty-four successive serum samples at points in the menstrual cycles of 12 healthy fertile women, precisely timed by measurement of the luteinizing hormone surge, and measured the interleukin-10 levels. RESULTS: Levels of IL-10 in successive serum samples from each woman taken on days LH - 7 (that is seven days prior to LH surge), LH - 4, LH + 1, LH + 7, and LH + 10 showed that IL-10 does not vary in a systematic way during the menstrual cycle. CONCLUSION: These results validate the sampling of women in studies of IL-10 levels in various clinical situations and establish that these levels are not dependent on menstrual cycle dates. They also suggest that menstrual cycle-related changes in IL-1 are not mediated by IL-10. The rise in progesterone in the luteal phase of the menstrual cycle is not mirrored by a rise in the circulating IL-10 level, which implies either that the pregnancy-associated rise is not related to progesterone or that it is only observed at the higher progesterone levels in pregnancy.

Adult↗
PubMed1996

The production of tumour necrosis factor alpha (TNF-alpha) by human endometrial cells in culture.

The production of tumour necrosis factor alpha (TNF-alpha) by cultured human endometrial epithelial and stromal cells prepared from endometrium obtained at different stages in the menstrual cycle has been investigated. TNF-alpha was not detectable in the supernatants of stromal cell cultures prepared from endometrial tissue obtained at any time in the menstrual cycle. TNF-alpha production by endometrial epithelial cells in culture varied depending on the time in the cycle at which the endometrial tissue was taken. Cells prepared from tissue obtained during the late proliferative phase of the cycle produced more TNF-alpha than those prepared from tissue obtained at other times in the cycle. In addition, a small increase in TNF-alpha production was seen by cells prepared from tissue obtained during the mid-secretory phase of the cycle. Interleukin 1 (IL-1) (1.4-140 pmol/l) caused a dose-dependent increase in TNF-alpha production by cells prepared from both proliferative and secretory endometrium. Maximum IL-1-stimulated increases in TNF-alpha production were similar in cells from both proliferative and secretory endometrium and typically reached from four to 10 times basal values. High doses of progesterone, either alone or in the presence of oestradiol, also affected TNF-alpha production by epithelial cells. TNF-alpha production by cells prepared from proliferative endometrium was increased by progesterone. In contrast, TNF-alpha production by cells prepared from secretory endometrium was decreased in the presence of progesterone. The effects of steroids on TNF-alpha production were less marked than that of IL-1, with values increasing or decreasing to a maximum of three times the basal value. Placental protein 14 (PP14) (0.18 and 1.8 nmol/l) also increased TNF-alpha production by cells prepared from proliferative tissue, but had no effect on its production by cells prepared from secretory endometrium. PP14-stimulated TNF-alpha levels typically only reached a maximum of two times basal values.

Cells, Cultured↗
PubMed1995

The production of placental protein 14 by human uterine tubal epithelial cells in culture.

Cells prepared from the mucosal layer obtained from the fimbrial, proximal ampullary and distal ampullary regions of the human uterine (Fallopian) tube have been grown in monolayer culture. Immunocytochemistry with anti-cytokeratin, anti-vimentin or anti-CD 45 antibodies indicated that the overwhelming number of cells were epithelial in nature and were free of fibroblasts and leukocytes. Basal and steroid-stimulated placental protein 14 (PP14) production was investigated in tissue obtained from nine patients undergoing hysterectomy, by addition of oestradiol and/or progesterone to confluent cultures. Basal PP14 production varied considerably between experiments, probably due to differences between individuals from whom the tissue had been obtained. However, there was no difference in basal PP14 production by cells prepared from the fimbrial, proximal ampullary and distal ampullary parts of the tube obtained from the same patient. When total PP14 production by cells obtained from an individual uterine tube was pooled both progesterone and oestradiol significantly (P < 0.05) stimulated the production of PP14 but the effect of progesterone either alone or in the presence of oestradiol was numerically greater than that of oestradiol alone. Considering PP14 production by cells prepared from the different regions of the tube showed that cells from the fimbrial region were more responsive to steroid stimulation than cells prepared from either the proximal or the distal ampullary regions. All combinations of hormonal supplementation stimulated PP14 production by cells from the fimbrial region on all days measured (P < 0.05 - P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1995

The measurement of CA 125 and placental protein 14 in uterine flushings in women with recurrent miscarriage; relation to endometrial morphology.

The concentrations of CA 125 and placental protein 14 (PP14) were measured in uterine flushings obtained throughout the luteal phase of the cycle from eight normal fertile women. The concentrations of both proteins increased in a similar pattern throughout the luteal phase of the cycle, with the most dramatic increase occurring 6 days after their luteinizing hormone surge (day LH +6). However, a greater variation in CA 125 concentrations was seen compared to that seen for PP14. The concentrations were compared to those obtained on day LH +7 of the cycle from a group (n = 35) of women with recurrent miscarriage. The ranges in concentration of PP14 and CA 125 in the flushings of fertile and recurrent miscarriage patients were very similar. However, a greater proportion of women with recurrent miscarriage (55%) had low concentrations (< 5 ng/ml) of PP14 than in the control group (12.5%) and the concentrations of PP14 in the uterine flushings were significantly less (P < 0.05) in women with recurrent miscarriage compared to the normal fertile group. There was no significant difference in the concentration of CA 125 in the uterine flushings between the two groups. Histological observation of the endometrial biopsy samples from recurrent miscarriage patients gave menstrual cycle datings that ranged from day LH +2.5 to LH +6.5 with retarded endometrium (< day LH +5) in 12 of 35 (34%) patients. Of these 12 patients, 10 (83%) had low PP14 concentrations and six (50%) had low CA 125 concentrations in their uterine flushings. In the recurrent miscarriage patients with histologically normal (> or = day LH +5) endometrial development, 10 out of 23 (43%) also had low PP14 concentrations and 8 out of 23 (35%) had low CA 125 in their uterine flushings. The results suggest that PP14 is better than CA 125 as a marker for endometrial function in this group of women. In some cases (52%) the low concentrations of PP14 in the uterine flushings could be explained by retarded endometrial development but for the others the reduction in PP14 concentration in the uterine flushing was not associated with retardation of endometrial development.

Abortion, Habitual↗
PubMed1994

Stimulation of human endometrial epithelial cell interleukin 6 production by interleukin 1 and placental protein 14.

The effect of interleukin 1 (IL1) and placental protein 14 (PP14) on the production of interleukin 6 (IL6) by cultured human endometrial epithelial cells prepared from endometrial biopsy material obtained at different stages in the menstrual cycle was investigated. Basal IL6 production by cells prepared from proliferative endometrium was greater than that produced by cells prepared from secretory endometrium (7.3 +/- 0.3 and 1.1 +/- 0.2 ng/well/24 h respectively, P < 0.001). IL1 (0.025-2.5 ng/ml) caused a dose-dependent increase in IL6 production by cells prepared from both proliferative and secretory endometrium, but cells prepared from secretory endometrium responded to a lower concentration of IL1 than those prepared from proliferative endometrium. IL-1-stimulated IL6 production by epithelial cells prepared from secretory endometrium typically reached 10 times basal values, while in cells prepared from proliferative endometrium stimulated levels were approximately twice the basal values. PP14 (1-50 micrograms/ml) also caused a dose-dependent increase in IL6 production by epithelial cells prepared from secretory endometrium, but had no effect on IL6 production by cells prepared from proliferative endometrium. Even in secretory cells PP14 was less effective than IL1 at stimulating IL6 production, with stimulated levels only reaching twice the basal values. This suggests that PP14 and IL1 act via different mechanisms in the stimulation of IL6 production. The results show that IL6 production by human endometrial epithelial cells is stimulated by other immunomodulatory peptides and this may be part of the network of such peptides in the endometrium which may influence embryo implantation.

Adult↗
PubMed1993

The production of placental protein 14 and interleukin 6 by human endometrial cells in culture.

Epithelial and stromal cells prepared from endometrium taken at different times in the menstrual cycle were grown in primary culture and the production of placental protein 14 (PP14) and interleukin-6 (IL6) measured. Only the epithelial cells produced PP14. Epithelial cells from endometrium in the late secretory phase produced significantly greater amounts of PP14 (42 +/- 5.8 ng/24 h) compared with that produced by cells from early secretory and proliferative endometrium (16 +/- 1.7 and 11 +/- 1.9 ng/24 h respectively). PP14 production by cells from endometrium at all stages in the cycle was increased by progesterone, or progesterone and oestradiol together, while oestradiol alone had no effect on PP14 production. The greatest stimulation was seen during the early secretory phase when stimulated levels of PP14 reached those obtained during the late secretory phase. IL6 production by epithelial cells also varied depending on the phase of the menstrual cycle. More IL6 was produced by the cells prepared from the endometrium in the proliferative phase (10.9 +/- 0.56 ng/24 h) compared with that produced by cells from early and late secretory endometrium (2.5 +/- 0.19 and 1.45 +/- 0.09 ng/24 h respectively). Addition of steroids to the media stimulated the production of IL6 by cells from proliferative and early secretory endometrium but decreased IL6 production from cells in the late secretory phase. IL6 was also produced by stromal cells but could only be detected in supernatants of cells prepared from late secretory endometrium, and the amounts produced (0.8 +/- 0.09 ng/24 h) were less than that produced by epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effects of chronic corticotrophin treatment on aldosterone metabolism in the rat.

Chronic treatment with high doses of ACTH leads to marked reduction in aldosterone biosynthesis and secretion both in vivo and in vitro. In contrast, it has been reported that peripheral plasma aldosterone levels may be elevated following prolonged ACTH treatment. The present study attempts to determine the reason(s) for this apparently paradoxical finding. ACTH treatment (40 micrograms/100 g body weight) of male Sprague-Dawley rats for 7 days caused a decrease of more than 90% in aldosterone secretion into the adrenal vein in vivo and aldosterone production by intact adrenal capsules incubated in vitro. In contrast, peripheral plasma aldosterone levels appeared to be increased when measured by radioimmunoassay using two different polyclonal antibodies (antibody 1 (AB1) raised against aldosterone-3-carboxymethyloxime-bovine serum albumin (BSA) and antibody 2 (AB2) raised against aldosterone-21-hemisuccinate-BSA). However, when a highly specific monoclonal antibody (raised against aldosterone-3-carboxymethyloxime-BSA and showing low cross-reactivity to aldosterone metabolites) was used, peripheral plasma aldosterone levels appeared to be reduced in ACTH-treated rats. Following chromatographic fractionation of peripheral plasma, significantly more material with aldosterone-like immuno-reactivity, but which was less polar than authentic aldosterone in chromatographic mobility, was detected in the fractions using antibodies AB1 and AB2. The absence of this material from fractions of adrenal vein plasma leads us to infer that this material is generated in the peripheral circulation, probably as a result of hepatic metabolism. In addition, the overall metabolic clearance rate (MCR) of [3H] aldosterone was found to be significantly decreased following prolonged ACTH treatment. We conclude that the seemingly discrepant findings with regard to the effects of chronic ACTH treatment on peripheral plasma aldosterone levels and the secretion of aldosterone in vivo can be reconciled by (1) the changes in the overall MCR of aldosterone and (2) the generation of increased quantities of aldosterone metabolites such as 5 alpha-dihydroaldosterone and 3 alpha, 5 beta-tetrahydroaldosterone which show significant cross-reactivity with some aldosterone antibodies.

Adrenal Glands↗
PubMed1992

Characterization of a rat adrenocortical inner zone-specific antigen and identification of its putative precursor.

We have previously reported the production of a monoclonal antibody (IZAb) which interacts with an antigen, found predominantly in rat adrenal inner zone tissue, which may have a role in steroidogenesis. Here we describe initial studies on its characterization. Immunoblot analysis of rat adrenocortical proteins obtained from fresh tissue and separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, showed that the IZAb interacted with a protein with a molecular mass of approximately 30,000 Da (IZAg1). This protein was found predominantly in rat adrenal inner zone tissue. Small amounts were seen in the zona glomerulosa, while no corresponding protein was seen in rat ovary, heart, liver, testis or kidney tissue. Subcellular fractionation of rat adrenocortical inner zone tissue and immunoblot analysis showed that the IZAg1 was present in the microsomal and mitochondrial fractions of the cell, but was absent from the cytosol. In-vivo treatment with ACTH (100 micrograms/day) for more than 5 days also increased the expression of this protein by rat adrenal inner zone tissue, and this was coincident with increased corticosterone and 18-hydroxydeoxycorticosterone (18-OH-DOC) production in incubations of inner zone tissue in vitro. In experiments involving the short-term culture of rat adrenal inner zone cells, IZAb interacted with two protein bands. IZAg1 was detected as a minor band in untreated control cells, while another protein with a molecular mass of approximately 60,000 Da, designated IZAg2, was present in greater amounts. Treatment of cells for 48 h with either ACTH (1 mumol/l) or dibutyryl-cAMP (100 mumol/l) resulted in apparent increased expression of IZAg1 and diminished levels of IZAg2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed1992

Origin of aldosterone in trypsin-stimulated rat adrenal zona glomerulosa incubations.

The time-course for the in-vitro secretion of aldosterone and 18-hydroxycorticosterone (18-OH-B) by rat adrenal whole capsular tissue (largely zona glomerulosa) was studied under control and stimulated conditions. The stimulatory effect of trypsin was relatively delayed, and the steroids were significantly enhanced only after 1 h, in contrast to the actions of ACTH, which produced effects after 15 or 30 min. Tissue-sequestered 18-hydroxydeoxycorticosterone (t-18-OH-DOC), which is not affected by ACTH, was significantly depleted by trypsin, but secreted 18-OH-DOC was not consistently affected by either stimulant. In contrast to the apparent mobilization of t-18-OH-DOC, the conversion of exogenously added [3H]18-OH-DOC to [3H]18-OH-B was inhibited by trypsin, and aldosterone was unaffected. When trilostane was added to inhibit de-novo steroidogenesis, under conditions in which the steroid secretory response to ACTH is completely inhibited, aldosterone and 18-OH-B secretion was still stimulated by trypsin although yields were lower. Compared with controls, trilostane reduced t-18-OH-DOC concentrations, and trypsin caused a further depletion. In other studies, glomerulosa plasma membrane enriched preparations were homogenized and centrifuged, and the supernatants were dialysed and added to incubations of dispersed zona glomerulosa cells in the presence or absence of stimulators of aldosterone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

18-Hydroxycorticosterone↗