Normal rats, on being repetitively stressed by being restrained in a tight container for two hours, had higher levels of plasma corticosterone compared to pre stress values. These rats also reacted to the stress by a behavioral response in which there was marked decrease in locomotor activity assessed by the open field test (pre stress: 71.3 +/- 2.6 squares crossed versus post stress: 14.3 +/- 2.5 squares crossed) by counting the number of squares entered by the rat over 5 minutes. By the 6th to 7th exposures to the repetitive stress, the rats adapted to the stress and had normal plasma corticosterone levels and locomotor activity scores comparable to the pre stress values. These responses to stress were completely blocked by the administration of 0.32 microg/100 g BW of naloxone i.p at 10 minutes prior to the stress. In rats fed with rat chow supplemented with 90 mg/kg rat chow or 150 mg/kg rat chow of vitamin E, there was significant reduction of the plasma corticosterone levels and improvement in the locomotor activity. Stress thus caused opioid mediated increase in plasma corticosterone and reduction in locomotor activity which could be blocked by naloxone. These stress responses probably also involved generation of oxygen free radicals which were scavenged by the vitamin E, thus reducing the effects of repetitive stress on locomotor activity and serum corticosterone levels.
The effects of stress and corticosterone on testicular 11beta-hydroxysteroid dehydrogenase (11beta-HSD) oxidative activity have been controversial, whilst that of adrenocorticotrophic hormone (ACTH) have not been investigated before. Hence, the aim of the present study was to determine the in vivo effects of stress due to injection and sham operation, ACTH and corticosterone on testicular and hepatic 11beta-HSD oxidative activity and plasma testosterone levels in normal and adrenalectomized (ADX) rats and their possible mechanism of actions. Adrenalectomy reduced both testicular 11beta-HSD oxidative activity and plasma testosterone levels. The effects of injection and sham operation significantly increased plasma corticosterone levels with decreased testicular 11beta-HSD oxidative activity and plasma testosterone levels in normal but not in ADX rats. Likewise. ACTH or corticosterone treatment for 7 days decreased both testicular 11beta-HSD oxidative activity in a dose dependent manner and plasma testosterone levels in normal rats; but the values in ADX rats remained unchanged. However, none of the above values were significantly lower than that of the ADX levels. Corticosterone seems to maintain testicular 11beta-HSD oxidative activity within the range between normal and ADX rats. These changes are not attributable to diurnal rhythms, as the time of sacrifice has been fixed between 8:30 and 10:30 am. In the liver, no significant change in 11beta-HSD oxidative activity was observed with sham operation, ACTH or corticosterone treatment; but adrenalectomy significantly decreased it. In conclusion, in the intact normal rats, stress, ACTH or corticosterone modulates testicular (but not hepatic) 11beta-HSD oxidative activity indirectly through the adrenal glands and the physiological level of corticosterone is ideal for normal reproductive functions.
11Beta-hydroxysteroid dehydrogenase (11beta-HSD) Type I enzyme is found in testis and liver. In Leydig cell cultures, 11beta-HSD activity is reported to be primarily oxidative while another report concluded that is primarily reductive. Hepatic 11beta-HSD preferentially catalyzes reduction and the reaction direction is unaffected by the external factors. Recent analysis of testicular 11beta-HSD revealed two kinetically distinct components. In the present study, various steroid hormones or glycyrrhizic acid (GCA), given for 1 week, or thyroxine given for 5 weeks to normal intact rats had different effects on the 11beta-HSD oxidative activity in testis and liver. Deoxycorticosterone, dexamethasone, progesterone, thyroxine, and clomiphene citrate increased testicular 11beta-HSD oxidative activity, but decreased hepatic enzyme activity except for deoxycorticosterone (unchanged). Corticosterone and testosterone decreased 11beta-HSD oxidative activity in testis but not that of liver (which was unchanged). Estradiol, GCA and adrenalectomy lowered oxidative activity of 11beta-HSD in testis and liver, but the degrees of reduction were different. The in vivo effects of glucocorticoids too were different, even in the same organ. Dexamethasone, a pure glucocorticoid, has greater affinity for glucocorticoid receptors (GR) than corticosterone. The direct effects of dexamethasone via GR in increasing testicular 11beta-HSD oxidative activity may override its indirect effects. Possibly, the reverse occurs with corticosterone treatment, as it has both glucocorticoid and mineralocorticoid effects. Because both organs have Type I isoenzyme, the difference in 11beta-HSD oxidative activities of these two organs could be attributable to the presence of an additional isozyme in testis or differences in tissue-specific regulatory mechanisms.
This study tested the possibility of adrenal autotransplantation in rats. Since the cortex and the medulla of the adrenal gland were from different origin embryologically, either whole adrenal glands (ADR), or capsule and cortex (CAP) or medulla (MED) were autotransplanted in the subcutaneous tissue. The functions of regenerated adrenal nodules were tested by measuring plasma corticosterone levels every fortnight. At the end of 9 weeks the rats were exposed to hypovolemic shock followed by naloxone injection to reverse the shock response. Results showed that rats transplanted with either cortex or whole adrenal started secreting corticosterone at 5 weeks post-transplantation (107.73 +/- 21.98 ng/ml, 126.04 +/- 48.41 ng/ml, respectively). Corticosterone levels increased to the value which were not significantly different from control by 9 weeks post-transplantation. However, rats transplanted with adrenal medulla showed very low corticosterone levels. Nine weeks post-transplantation, the mean blood pressure (MBP) of the CAP group was 135 +/- 13 mmHg and was not significantly different from sham-operated controls, whereas MBP of MED group was significantly lower than sham-operated animals (99 +/- 11 mmHg versus 141 +/- 9 mmHg). The MBP of the ADR group was also lower compared to sham-operated controls (112 +/- 17 mmHg P < 0.05). The MBP of the adrenal group was not statistically significant compared to the CAP group. After 1% body weight haemorrhage, the MBP decreased significantly in ADR (45 +/- 5 mmHg, P < 0.05) and MED group (36 +/- 9 mmHg, P < 0.001) compared to sham-operated rats (78 +/- 11 mmHg) but not in the CAP (56 +/- 9 mmHg). It was concluded that autotransplanted whole adrenal or adrenocortical tissues survived subcutaneously and produced sufficient corticosterone to alleviate haemorrhagic shock. Adrenal medullary tissue failed to regenerate subcutaneously and the presence of adrenal medullary tissue may suppressed the growth of transplanted adrenal gland.
An in-house radioimmunoassay (RIA) for the measurement of androstenedione levels in serum was established and validated. Levels of androstenedione were measured by RIA using serum samples from various normal population groups and patients with congenital adrenal hyperplasia (CAH). Analytical recovery and linearity results were > 95%, while intra- and inter-assay CVs were < 10% and < 22% respectively. The assay sensitivity was 0.5 nmol/l or 25 fmol/tube. In normal population groups, the highest androstenedione levels were found in preterm neonates (1.6-12.4 nmol/l), followed by adult females (1.5-10.2 nmol/l), adult males (1.6-8.0 nmol/l) and term neonates (0.8-8.8 nmol/l), while the lowest values were observed in prepubertal children (0.5-3.4 nmol/l). There were no significant differences in diurnal variation and between follicular and luteal phases. The range of androstenedione levels in untreated or poorly controlled CAH patients (7.6-355.0 nmol/l, median 42.5 nmol/l, n = 20) were significantly higher (p < 0.001) than the upper normal limit of 3.4 nmol/L for prepubertal children. The normal androstenedione reference ranges for paediatric and adult groups have thus been established.
1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.
The purpose of this study is to explore the types of problem students that clinical teachers encounter in clinical settings. A questionnaire developed by the Association of American Medical Colleges that lists a variety of types of problem students was completed by 466 clinicians at the University of Washington School of Medicine (UWSOM) and 98 Malaysian clinicians from Universiti Kebangsaan Malaysia (UKM) and Universiti Sains Malaysia (USM). In addition, 120 medical students from UKM completed a slightly modified version of this questionnaire. Both the faculty and student questionnaires asked the respondent to identify the frequency of a given problem type. The faculty was also asked to estimate how difficult it was to evaluate a specific problem. In general, there was strong agreement among the North American and Malaysian faculty on the frequency and difficulty of the 24 types of problem students listed. There were some notable differences, such as Malaysian teachers perceiving the "shy" student more frequently than their North American counterparts who rated the student with deficits in knowledge more frequently. However, the overall similarity in the rankings suggest that clinical teachers face similar types of problems, independent of cultural differences and institutional differences.
A supersensitive ELISA was developed for measurement of thyroid-stimulating hormone (TSH) concentrations in serum using in-house rabbit polyclonal antisera and a commercial monoclonal antibody. The assay was optimised and validated by recovery, linearity and cross-reactivity experiments and further compared to other available assays and EQAS samples. Good precision was obtained with a working assay range of 0.2 to 100 mIU/L with < 10% coefficient of variation (CV) for both intra and interassay. The assay is highly sensitive and specific with a minimum detectable limit of 0.07 mIU/L and negligible cross-reactivities against LH, FSH, HCG and other pituitary peptides. Good correlations were obtained when compared to Abbott hTSH EIA (r = 0.993; p < 0.001; n = 85) and NETRIA IRMA (r + 0.995; p < 0.001; n = 76). The normal reference range established was 0.4 to 4.0 mIU/L (n = 76). TSH levels in serum of thyrotoxic patients (n = 83) were significantly lower (0.07 to 0.20 mIU/L, p < 0.0001) and completely distinct from normal values thereby obviating the requirement of a TRH-stimulation test. Stability studies showed that coated wells can be stored at 4 degrees C for at least 2 months. This highly sensitive in-house hTSH ELISA which is cheap, stable and readily available is useful for diagnosis and management of patients with various thyroid disorders.
The effect of ovariectomy and sex hormone/s replacement in female rats was investigated by the determination of the tumour marker enzymes gamma-glutamyltranspeptidase (GGT) and alkaline phosphatase (ALP). This was compared to ovariectomized rats receiving sex hormone replacement and treated with carcinogen. Ovariectomy significantly increased the activity of plasma GGT. Plasma and microsomal ALP and microsomal GGT were unchanged. When replacements of estrogen (E), or progesterone (Prog), or combinations of both estrogen and progesterone were given to ovariectomized rats, the activity of plasma GGT was brought to the level of normal intact females. Treatment with carcinogen increased the PGGT activities in intact rats. In ovariectomized rats receiving carcinogen, the PGGT activities were significantly lower than in intact females and rats receiving both hormone replacement and carcinogen (p < 0.01). Carcinogen treatment in case of estrogen or progesterone replacement, either individually or in combination, showed GGT activities comparable to intact females receiving carcinogen. Both plasma and microsomal ALP were not affected by carcinogen administration. These results showed that ovariectomy reduced the severity of hepatocarcinogenesis while sex hormone replacement worsened the process.
Growth hormone (GH) levels were measured after a 75g oral glucose load (OGTT) in normal adults, patients with impaired glucose tolerance (IGT), insulin-dependent diabetes mellitus (IDDM) and acromegaly. Nadir GH levels at 2-hour post-OGTT in normal subjects ranged from 0.4 to 8.4 mIU/L, the 95% confidence interval being 0.4-4.4 mIU/L. In IGT and IDDM subjects basal fasting GH levels were not significantly different from normal and did not alter during OGTT. The high fasting GH level measured in one each of the IGT and IDDM patients was suppressible at 1-hour after glucose intake. In contrast, acromegalic patients had elevated fasting GH levels (11.8-178 mIU/L) although in 3 patients, the levels were mildly elevated and overlapped with normal. OGTT failed or only partially suppressed GH secretion in all acromegalics. Therefore, elevated fasting GH levels are not diagnostic and OGTT is required for accurate diagnosis and assessment of treatment of acromegalic patients.
1. Glucocorticosteroid may relieve bronchospasm by mediating changes in the muscarinic receptor concentration and/or its affinity. 2. Cholinergic muscarinic receptors were determined by using Scatchard's plots from radioligand binding assays of 0.13-3.2 nM [3H]quinuclidinyl benzylate binding to the membrane fraction of bronchial smooth muscle (BSM). 3. The concentration of muscarinic receptor in BSM of normal rat was 57 +/- 3 fmol mg protein and the dissociation constant was 0.07 +/- 0.02 nM. Dexamethasone and corticosterone reduced muscarinic receptor concentration to 50-60% of basal with no changes in receptor affinity. No changes were found in rat treated with deoxycorticosterone. 4. These findings suggest that glucocorticoids but not mineralocorticoid relieve bronchospasm at least partly by reducing the cholinergic hypersensitivity.
Twelve cases of primary hyperparathyroidism operated by the Universiti Kebangsaan Malaysia Surgical Team from 1978 to 1989 were reviewed. There was a preponderance of Indian females in this series. The majority of the cases presented late and with complications. Renal calculi and bone disease were the commonest complications noted. Of the 12 patients, 9 had single parathyroid adenoma of which 4 were ectopically located, and 2 had hyperplasia of the parathyroids. These were all successfully operated. The remaining patient had 2 failed neck explorations. Failure at initial exploration was due to ectopic location of the glands. Meticulous surgical technique, knowledge of the anatomical variations of location of the parathyroid glands and availability of frozen section facility are essential for successful outcome.
62 cases of polycystic ovary syndrome (PCO) were reviewed with regards to their clinical and endocrine features. The subgroup of patients with acanthosis nigricans (AN) was further studied in detail. The prevalence of the syndrome was significantly higher in the Indian (35.5% of cases). Obesity, AN, hirsutism, non-insulin dependent diabetes mellitus (NIDDM) and raised level of serum testosterone were present in 77.1%, 74%, 79%, 21% and 48% of the cases respectively. Patients with AN was associated with higher body mass index, serum testosterone level, and prevalence of hirsutism and NIDDM than patients without AN. These observations are in keeping with the hypothesis that hyperinsulinemia may be of importance in the pathogenesis of a sub-group of PCO associated with insulin resistant states.
A 44 year old lady with primary hypothyroidism presented with massive pericardial effusion without cardiac tamponade. Pericardial tap was done twice and the effusion resolved as the hypothyroid state improved. She remained hypertensive despite the euthyroid state. She was discharged well with L-thyroxine and anti-hypertensive therapy.
One hundred and six prostatic tissue samples obtained from transurethral resection were analysed for androgen and estrogen receptors. In 62 of these, progesterone and glucocorticoid receptors were also assayed. Steroid receptors were assayed using single saturation dose 3H-labelled ligand assays. Ninety percent of the 97 prostatic hyperplasia tissues and six of the nine prostatic carcinoma tissues were positive for androgen receptors. Estrogen receptors were only present in 19% and 33% respectively. Progesterone receptors were present in 70% of the tissues, but glucocorticoid receptors were present in only 16% of prostatic hyperplasia and none in prostatic carcinoma.
Adrenal histoplasmosis in Cushing's syndrome of adrenal origin is rare. A patient with Cushing's disease with bilateral nodular hyperplasia and histoplasmosis of both the adrenal glands is described. The diagnosis of histoplasmosis was only made post operatively as the constitutional manifestations, besides being partially masked by hypercortisolism also resemble those of tuberculosis.
1. Steroid hormones have been shown to regulate the concentration of adrenergic and muscarinic receptors in many tissues. 2. The cyclic adenosine 3',5'-monophosphate (cAMP) content in rat lung tissues in response to either dexamethasone, corticosterone, deoxycorticosterone or progesterone for 7 days were measured following intraperitoneal injection of isoprenaline just before sacrificed. 3. There was a significant increase in cAMP level (P less than 0.001) in dexamethasone and corticosterone-treated rats compared to controls that received isoprenaline alone. 4. Pretreatment with deoxycorticosterone and progesterone suppressed the increase in cAMP in response to isoprenaline. 5. The effect of glucocorticoids in causing bronchodilatation in asthmatic patients is partly due to the restoration of adenyl cyclase responsiveness to beta-agonist.
The clinical, biochemical and immunological features of 180 patients with hyperthyroid Graves' disease managed at the Universiti Kebangsaan Malaysia (UKM) Endocrine Clinic from 1983 to 1987 were examined. The prevalence of the disease is highest in Chinese and lowest in Indians. The female: male ratio is 2.8:1. Hypokalaemic periodic paralysis and hypercalcaemia were present in 5.0% and 1.7% of the cases respectively. Pretibial myxoedema was extremely rare. Thyrotropin - binding inhibitory immunoglobulins, anti-thyroglobulin and anti-microsome antibodies were positive in 61.5%, 25.8% and 42.3% of the patients respectively. A eumetabolic state could be achieved in the majority of patients with antithyroid drugs alone. Definitive therapy with subtotal thyroidectomy or radioiodine were needed in 31.3% of cases.
1. The effects of corticosteroid pretreatment on acetylcholine (ACH)-induced contraction of bronchial smooth muscle (BSM) were studied. 2. ACH dose-response curves for dexamethasone (DM)- and corticosterone (B)-treated but not deoxycorticosterone (DOC)-treated BSM were significantly shifted to the right; this provides evidence that glucocorticoid treatment reduced the sensitivity of BSM to ACH. 3. Morphine enhanced BSM contraction in response to ACH by 20%. DM suppressed this enhancement. 4. These findings correlated well with the reduction of muscarinic receptor numbers in BSM by glucocorticoids in our previous study. In addition, glucocorticoids reduced the sensitivity of BSM to opioids.
1. Free radicals generated by ferric nitrilotriacetate (FeNTA) can activate osteoclastic activity and this is associated with elevation of the bone resorbing cytokines interleukin (IL)-1 and IL-6. In the present study, we investigated the effects of 2 mg/kg FeNTA (2 mg iron/kg) on the levels of serum IL-1 and IL-6 with or without supplementation with a palm oil tocotrienol mixture or alpha-tocopherol acetate in Wistar rats. 2. The FeNTA was found to elevate levels of IL-1 and IL-6. Only the palm oil tocotrienol mixture at doses of 60 and 100 mg/kg was able to prevent FeNTA-induced increases in IL-1 (P < 0.01). Both the palm oil tocotrienol mixture and alpha-tocopherol acetate, at doses of 30, 60 and 100 mg/kg, were able to reduce FeNTA-induced increases in IL-6 (P < 0.05). Therefore, the palm oil tocotrienol mixture was better than pure alpha-tocopherol acetate in protecting bone against FeNTA (free radical)-induced elevation of bone-resorbing cytokines. 3. Supplementation with the palm oil tocotrienol mixture or alpha-tocopherol acetate at 100 mg/kg restored the reduction in serum osteocalcin levels due to ageing, as seen in the saline (control) group (P < 0.05). All doses of the palm oil tocotrienol mixture decreased urine deoxypyridinoline cross-link (DPD) significantly compared with the control group, whereas a trend for decreased urine DPD was only seen for doses of 60 mg/kg onwards of alpha-tocopherol acetate (P < 0.05). 4. Bone histomorphometric analyses have shown that FeNTA injections significantly lowered mean osteoblast number (P < 0.001) and the bone formation rate (P < 0.001), but raised osteoclast number (P < 0.05) and the ratio of eroded surface/bone surface (P < 0.001) compared with the saline (control) group. Supplementation with 100 mg/kg palm oil tocotrienol mixture was able to prevent all these FeNTA-induced changes, but a similar dose of alpha-tocopherol acetate was found to be effective only for mean osteoclast number. Injections of FeNTA were also shown to reduce trabecular bone volume (P < 0.001) and trabecular thickness (P < 0.05), whereas only supplementation with 100 mg/kg palm oil tocotrienol mixture was able to prevent these FeNTA-induced changes.