Regulation of the aldosterone secretion in the frog Rana esculenta L.

The concentration of aldosterone in plasma of the frog Rana esculenta L. has been measured by radioimmunoassay without chromatography. In the normal frogs, the concentration of this steroid is 0.82 ± 0.16 μg/100 ml in the plasma of blood removed by heart puncture. Using daily administration of metopirone or aminoglutethimide, the steroid is no more detectable after six injections. Hypophysectomy produces, 15 days after the operation, a small but significant diminution of the hormone concentration. On the contrary, one administration of synthetic ^1–24ACTH, or extract of frog kidney, produces an elevation of the aldosterone level, not only in the normal, but also in the hypophysectomized frogs. These results suggest that, in the amphibians, the aldosterone level depends on the renin-angiotensin system and pituitary ACTH.On the other hand, the injection of corticosterone into normal frogs produces a significant decrease of aldosterone concentration, which suggests feedback mechanisms in the control of aldosterone secretion.     

The in vitro response of the trout interrenal to various fragments of ACTH

The ability of various fragments of ACTH to stimulate cortisol secretion was tested in vitro using diced interrenal tissue from the rainbow trout Salmo gairdneri. 1–24ACTH induced maximum steroidogenesis at a concentration of 5 × 10^?8M, and a half-maximal response at 0.8 × 10^?9M. Des-acetyl-αMSH (1–13NH₂ACTH) had full intrinsic activity; its molar potency was 0.9 × 10^?2-fold less than 1–24ACTH but nearly 100-fold greater than acetylated αMSH. 1–10ACTH had an even lower potency, while 4–10ACTH was without effect at the highest concentration tested (5 × 10^?5M). The fragment 1–16ACTH was unusual in eliciting a higher maximum cortisol concentration than 1–24ACTH. These findings suggest that the increase in plasma cortisol, previously observed in trout adapted to a black background, are unlikely to be directly attributable to adrenal stimulation by the raised MSH titres.     

Corticotropic effects on isolated interrenal cells of the turtle (Chrysemys picta)

An investigation was carried out to determine whether isolated interrenal cells of the turtle could be used as a biossay for reptilian cortocotropin. The action of synthetic ACTH, ACTH analogs, and naturally occurring corticotropins of four vertebrate classes were compared. A typical sigmoid log dose response (LDR) curve was elicited with 1–10⁶ pg/ml of ACTH_1–24 and pACTH (3rd IWS), and crude extracts of homologous chelonian or avian adenohypophyses gave similar responses. Potency in ACTH_1–24 equivalents was as follows: pACTH, 10 pg/μU; chelonian pituitary, 80 pg/μg (wet wt); avian pituitary, 160 pg/μg (wet wt). Corticotropic activity was present in Rana pituitary, but the maximum response was half that obtained with the other corticotropins and relative potency could not be estimated. Molar potency of ACTH analogs tested on isolated turtle cells decreased in the following order: ACTH_1–24 > ACTH_1–16 > ACTH_1–13 ～ ACTH_7–13 > β-MSH > ACTH_4–10. The maximum response obtained with ACTH_1–16 was 80% of that with ACTH_1–24, but insufficient quantities of other analogs were available for complete LDR curves. Molar potency comparisons suggest that, in the reptile, amino acids 11–24 but not 1–6 are important for receptor binding. Further, the portion of the molecule essential for maximal receptor activation spans amino acids 1–16 and 17–24. The intrinsic activities of mammalian, avian, and reptilian corticotropin are approximately equivalent but twice that of amphibian corticotropin in a reptilian interrenal system.     

In vitro study of frog (Rana ridibunda pallas) interrenal function by use of a simplified perifusion system. V. Influence of adrenocorticotropin upon progesterone production

The dynamics of progesterone production by perifused frog adrenal explants has been investigated under pituitary stimulation. Specific progesterone antibodies have been raised in rabbits and a radioimmunoassay has been developed. The sensitivity of the assay and the low cross-reactivity of the antiserum with the major corticosteroids produced by the interrenal tissue, mainly corticosterone (0.7%) and aldosterone (0.002%), made it possible to measure progesterone concentrations in 150-μl samples of effluent perifusate, without prior extraction of purification. The validity of the method was confirmed on Sephadex LH-20 gel chromatography. A direct effect of temperature variations on progesterone output was demonstrated in the temperature range 5–30°, which strongly suggested that external temperature controls progesterone synthesis by the interrenal gland in vivo. In the presence of distal lobe homogenates a linear log-dose increase in progesterone output was observed. The use of ACTH 1–24 as a reference standard made it possible to compare the biological activity of crude distal lobe homogenates from frog pituitary and synthetic ACTH. The effect of neurointermediate lobe extracts on progesterone production was also studied. At a concentration as low as 0.006 neurointermediate lobe eq/ml, a 2.1-fold increase in progesterone output was observed suggesting a very high concentration of ACTH-like material in frog pars intermedia. As far as is known the present data provide the first unequivocal evidence that, in frog, intact interrenal cells produce significant amounts of progesterone in vitro. Our results demonstrate also that synthetic ACTH and pituitary extracts stimulate progesterone output and that the dynamics of the steroidogenic response to various stimulants was virtually the same with progesterone, corticosterone, or aldosterone.     

Immunosuppressive effects of corticotropin and melanotropin and their possible significance in human immunodeficiency virus infection.

The activation of human granulocytes and invertebrate immunocytes was found to be suppressed by corticotropin (ACTH) and melanotropin (MSH). In spontaneously active granulocytes both neuropeptides caused significant conformational changes indicative of inactivity plus a reduction in their locomotion. Significant inactivation of human granulocytes by ACTH required 2 hr, that by MSH only 20 min. The addition to the incubation medium of phosphoramidon, a specific inhibitor of neutral endopeptidase 24.11, blocked inactivation of granulocytes by ACTH. Radioimmunoassay for MSH of supernatant fluids from granulocytes incubated with ACTH demonstrated a time-dependent increase in MSH. These data strongly indicate that the effect of ACTH is largely due to its conversion to MSH by granulocyte-associated neutral endopeptidase. Parallel experiments with immunocytes from the mollusc Mytilus edulis gave similar results, indicating the universality of this phenomenon. Our finding that the human immunodeficiency virus, among several viruses, induces ACTH and MSH production in H9 T-lymphoma cells suggests an important role of these neuropeptides in the immunosuppression characteristic of such infections.     

STUDIES OF CIRCULATING PARATHYROID HORMONE IN MAN USING A HOMOLOGOUS AMINO-TERMINAL SPECIFIC IMMUNORADIOMETRIC ASSAY

Circulating immunoreactive parathyroid hormone (PTH) was measured by a homologous, amino-terminal, specific, immunoradiometric assay in man. In forty-two healthy subjects the concentrations ranged between < 40 pg/ml and 120 pg/ml. No hormone could be detected in the sera of eleven patients with hypoparathyroidism, but the concentrations were clearly elevated in six patients with pseudohypoparathyroidism (range 190–1120 pg/ml). In thirty-five patients with primary hyperparathyroidism the mean (±SEM) concentration was 283·4±42·4 pg/ml (range 100–1350 pg/ml). A significant positive correlation was demonstrated between immunoassayable hormone and serum calcium concentrations in these patients. In nine patients PTH concentrations were measured before and after parathyroidectomy. In all of them they were elevated pre-operatively but fell to the normal range after parathyroidectomy. The disappearance of exogenously administered synthetic human PTH (1–34) from the circulation of two normal subjects was rapid with an apparent plasma half-disappearance time (t½) between 2 and 3 min; the metabolic clearance rate was 12·9 and 9·0 ml. kg^-1, min^-1 respectively. Similarly, the disappearance of endogenous, amino-terminal, immunoreactive PTH from the circulation of two patients with primary hyperparathyroidism after parathyroidectomy was rapid; the apparent t½ was approximately 3 min. Homologous amino-terminal specific immunoassays for PTH can thus be useful for the study of both the acute, and chronic, changes of circulating hormone in man and represent an improvement over heterologous unselected assay systems.     

Fine structure of the secretory activity of the pars intermedia of Rana pipiens

The partes intermedia of adult, Rana pipiens, white- and black-background adapted for 14 days (MI 1.0–1.5 and 4.5–5.0, respectively), were studied with electron microscopy. Thus, ultrastructural characteristics of nonsynthesizing/nonsecreting versus synthesizing/secreting melanophore-stimulating hormone (MSH) cells were established. Cytoplasmic granules of varying size (150–300 nm) and electron density appeared in far greater numbers in the secretory cells of white-adapted animals than those of black-adapted. The latter contained only smaller (150–200 nm), more dense granules. The rough endoplasmic reticulum (rER) of the black-adapted frogs was well developed, and the dilated rER cisternae contained a filamentous precipitate. The rER of the white-adapted frogs was reduced.The neurointermediate lobes of black-adapted frogs were transplanted into the anterior chamber of the eyes of nine black-adapted frogs, which were then maintained on a black background three additional days. The ultrastructure of 85–90% of the cells of both transplanted and in situ partes intermedia appeared similar to that of a white-adapted animal. These cells showed numerous granules and reduction in rER. Again, nine black-adapted frogs served as donors of intraocular transplants for nine black-adapted recipients. Then the hosts were placed on a white background for 3 days and showed skin darkening (MI 4.5–5.0). This experiment indicated that the transplant was not under hypothalamic control. The transplanted glands contained cells similar to those found in the black-adapted frog; the cells of the host pars intermedia were comparable to those of a white-adapted frog. Finally, six frogs were black background adapted and injected with porcine α-MSH (1 × 10^?7 g/m²) every 2.5 hr for 3 days. Glands of these animals were similar to those of black-adapted frogs containing transplants; they contained many cytoplasmic granules. It appears that exogenous MSH, either of transplanted or injected origin, inhibits the synthesis and release of granules which have been considered MSH. It appears that MSH is acting at the pituitary level rather than the hypothalamic level to produce this inhibition. The intact pituitary remained under hypothalamic control, but the transplanted one did not. These results suggest a direct feedback in which circulating MSH affects release and further synthesis of MSH. The exact role of this mechanism in normal physiological control of color change is not known.     

Homocysteine and cysteine: determinants of plasma levels in middle-aged and elderly subjects

Abstract. Objectives. Hyperhomocysteinaemia is an independent risk factor for cardiovascular disease. We explored possible determinants of plasma homocysteine and cysteine concentrations amongst middle-aged and elderly subjects. Design and subjects. Of 501 35–95-year-old randomly selected residents of Lund and Malmö, Sweden, 244 (49%; 131 men, 113 women) were investigated. Results. Total plasma homocysteine concentrations were higher in men than in women (mean ± SD: 13.9 ± 4.1 and 12.3 ± 4.1 μmol L^?1; P < 0.001), increased markedly with age (Spearman's p = 0.488; P < 0.001), and were correlated (P < 0.001) to concentrations of blood folate, serum vitamin B₁₂, and serum creatine (p = ?0.366, ?0.338, and 0.463). Users of multivitamins had lower homocysteine levels than nonusers [10.5 ± 3.3 μmol L^?1 (n = 31) and 13.5 ± 4.2 μmol L^?1 (n = 213), respectively; P < 0.001]. Total plasma cysteine concentrations also increased significantly with age and increasing serum creatinine, but were unrelated to gender, blood folate, serum vitamin B₁₂ and use of multivitamins. Conclusions. Age, gender, folate, serum vitamin B₁₂, serum creatinine and multivitamin usage are all important determinants of the plasma homocysteine concentration, whereas only age and serum creatinine are determinants of the plasma cysteine concentration. The age-related increase in homocysteine and cysteine may be linked to the age-related impairment of renal function, whereas the sex difference in plasma homocysteine may be because of the fact that more homocysteine is formed in men than in women in conjunction with creatine-creatinine synthesis.     

Nerve growth factor and expression of its receptors in patients with diabetic neuropathy

Aims Low serum nerve growth factor (NGF) levels have been reported in patients with diabetic peripheral neuropathy (DPN), but the role of NGF in the development of neuropathy is unclear. Thus, we investigated the associations of serum NGF level and NGF receptor activity with the presence and severity of DPN. Methods One hundred and thirty‐six patients with Type 2 diabetes were included in this cross‐sectional study. Serum NGF levels were measured by ELISA. Expressions of NGF receptors (TrkA and p75^NTR) were measured by immunohistochemical staining. The presence and severity of DPN were assessed by neuropathy disability score (NDS) and by corneal nerve fibre length (cNFL) and nerve branch density (cNBD) using in vivo confocal microscopy. Results Patients with DPN had higher serum NGF levels (56–451 pg/ml) than patients without DPN (4–54 pg/ml). However, in DPN patients, serum NGF was negatively associated with neuropathy severity (mild 222 ± 64 pg/ml; moderate 114 ± 17 pg/ml; severe 89 ± 20 pg/ml). This negative association was consistent in all severity indices (NDS, P < 0.001; cNFL, P < 0.001; cNBD P = 0.010) even after adjustment for age, sex, diabetes duration, insulin use, fasting glucose and glycated haemoglobin. Although NGF receptor activities had significantly (P < 0.05) negative associations with the presence and severity of neuropathy, these associations were not significant when adjusted for other factors. Conclusions Serum NGF level was positively associated with the presence of DPN but negatively associated with neuropathy severity in DPN patients. The change in serum NGF might be a consequence of, rather than a contributor to, the early development of DPN.     

Corticotropin releasing hormone and arginine vasopressin stimulation of ACTH and substance P in human mononuclear leukocytes.

Bacterial lipopolysaccharide (LPS) and corticotropin releasing hormone (CRH) plus arginine vasopressin (AVP) induce immunoassayable (1-13)ACTH (alpha MSH) from mononuclear leukocytes. We studied the ability of LPS and CRH + AVP to in vitro stimulate native ACTH (not alpha MSH) and substance P (SP) production and thymidine incorporation in human mononuclear leukocytes. Neither CRH + AVP nor LPS stimulated detectable amounts of intracellular or extracellular ACTH (less than 15 pg/8 x 10(6) cells or total medium) or SP (less than 50 pg/8 x 10(6) cells or total medium) at 1, 2, 3 or 4 days of incubation. LPS, but not CRF + AVP, increased the amount of 3H-thymidine incorporation over controls. This data questions the importance of an immunoadrenal axis and the synthesis of SP by mononuclear leukocytes.     

Elevated plasma 19-hydroxyandrostenedione levels in Cushing's disease: stimulation with ACTH and inhibition with metyrapone

OBJECTIVE The regulation of 19-hydroxyandrostenedione secretion has been suggested to be under the control of both the ACTH-adrenal axis and renin-angiotensin system. We undertook the present study to evaluate the effect of the chronic excess of ACTH, or the short-term excess of ACTH due to metyrapone, on 19-hydroxyandrostenedione secretion in patients with Cushing's disease DESIGN AND PATIENTS We measured plasma 19-hydroxyandrostenedione levels simultaneously with plasma Δ⁴-androstenedione, corticosterone, 11-deoxycorticosterone, aldosterone and Cortisol levels after HPLC separation in 13 patients with Cushing's disease under basal conditions and during a dexamethasone suppression test or metyrapone test. Seven patients with Cushing's syndrome due to adrenal adenoma were used for comparison. RESULTS The basal levels of 19-hydroxyandrostenedione in Cushing's disease were elevated (mean ± SD; 323 ± 193 pmol/l, n= 13), while those in Cushing's syndrome due to adrenal adenoma were low (92 ± 24 pmol/l, n= 7), compared to those in normal subjects (117 ± 33 pmol/l, n= 54). The basal levels of Δ⁴-androstenedione were mildly elevated In Cushing's disease (9.0 ± 6.5 vs 3.6 ± 2.6 nmol/l of normal subjects) but not in Cushing's syndrome due to adrenal adenoma (3.1 ± 3.0 nmol/l). In the overnight 8 mg dexamethasone suppression test in Cushing's disease (n= 12), plasma levels of 19-hydroxyandrostenedione and Δ⁴-androstenedlone decreased from 277 ± 172 to 156 ± 99 pmol/l and from 9.2 ± 6.8 to 4.7 ± 3.4 nmol/l, respectively, whereas the overnight 1 mg dexamethasone suppression test did not induce significant changes. Metyrapone administration in Cushing's disease (n= 9) increased plasma Δ⁴-androstenedione level from 9.5 ± 6.7 to 47.2 ± 28.1 nmol/l, but decreased plasma 19-hydroxyandrostenedione level from 301 ± 196 to 196 ± 105 pmol/l. CONCLUSIONS These data indicate that plasma levels of 19-hydroxyandrostenedione in patients with Cushing's disease are elevated due to chronic ACTH excess, and that metyrapone can inhibit 19-hydroxylation in humans.     

Immunohistochemistry and Tinctorial Affinity of Adenohypophysial Cells of the Rat SnakePtyas mucosus(Colubridae)

Immunocharacteristics of the adenohypophysial cells of the rat snakePtyas mucosus(Colubridae) were studied with an unlabeled antibody enzyme technique (PAP method) using rabbit antisera against mammalian/synthetic hypophysial hormones. Adenohypophysial cells were identified on the basis of their specific immunoreactivity with various heterologous antisera. As in other reptiles, there was regional localization of pars distalis (PD) cell types in this snake. The gonadotropic (GTH) cells were identified by their specific immunoreactivity with anti-porcine (p)LHβ serum and were distributed uniformly throughout the PD. The thyrotropic (TSH) cells, recognized by their specific immunoreactivity with anti-human (h)TSHβ serum, were found in the medial PD. The prolactin (PRL) and growth hormone (GH) cells were revealed by their specific immunoreactivity with anti-ovine (o)PRL and anti-hGH sera, respectively; the former were confined to the anterior two-thirds of the PD, and the latter were restricted to the posterior third of the PD. The corticotropic (ACTH) cells, identified by their specific immunoreactivity with the anti-ACTH^1–24serum, were localized in the anterior two-thirds of the PD. Though both ACTH and PRL cells were confined to the same area of the PD, they could be distinguished by their distinctive morphology and distribution pattern. Cells of the pars intermedia were revealed by their immunoreactivity to anti-αMSH (melanophore-stimulating hormone) and anti-ACTH^1–24sera. Among each adenohypophysial cell type, there was variation in the intensity of immunoreactivity and morphological features, which may be due to their heterogeneity, reflecting various stages of cellular activity. Unlike most other snake species, the occurrence of a rudimentary pars tuberalis inP. mucosuscontaining a few immunoreactive GTH and TSH cells appeared to be a novel finding. The occurrence of the PRL-like and TSH-like immunoreactivity seen in certain neuronal perikarya and fibers of the hypothalamus and median eminence conforms with earlier observations in other tetrapods. To resolve certain discrepancies in the literature, the tinctorial affinities of immunohistochemically identified adenohypophysial cell types ofP. mucosuswere studied using various conventional staining methods and were compared with those of other reptilian species studied earlier, including snakes of the family Colubridae.     

Post-therapeutic recovery of serum interleukin-35 level might predict positive response to immunosuppressive therapy in pediatric aplastic anemia

Background: The predictive value of interleukin-35 (IL-35) on efficacy of immunosuppressive therapy (IST) in aplastic anemia (AA) has not been well investigated. The aim of the study was to evaluate the association between serum IL-35 level and response to IST in pediatric AA.

Methods: A total of 154 children with AA and 154 controls were included between January 2012 and December 2013. Blood and bone marrow fluid specimens were collected. Serum level of IL-35 was determined by enzyme-linked immunosorbent assay. Patients were treated with IST, and response to therapy was evaluated during 180-day follow-up period after starting therapy.

Results: Serum levels of IL-35 at admission decreased significantly in patients compared with that in controls (10.9?±?5.5?pg ml^?1 and 45.3?±?8.8?pg ml^?1, p??1 in the first 28 days (p??1 in the first 28 days was associated with effective response to therapy (odds ratio 7.97, 95% confidence interval 3.82–16.79). In addition, Fas/FasL protein expression in bone marrow mononuclear cells dropped significantly in the same group of patients in the first 28 days (p?Conclusion: The study revealed that post-therapeutic recovery of circulating IL-35 concentration might be an independent predictor for effective response to IST in pediatric AA. Moreover, apoptosis might be involved in such a forecasting process.     

Reduced Plasma Aldosterone Concentrations in Randomly Selected Patients with Insulin-dependent Diabetes Mellitus

Abnormalities of the renin-angiotensin system have been reported in patients with diabetes mellitus and with diabetic complications. In this study, plasma concentrations of prorenin, renin, and aldosterone were measured in a stratified random sample of 110 insulin-dependent (Type 1) diabetic patients attending our outpatient clinic. Fifty-four age- and sex-matched control subjects were also examined. Plasma prorenin concentration was higher in patients without complications than in control subjects when upright (geometric mean (95 % confidence intervals (CI): 75.9 (55.0–105.6) vs 45.1 (31.6–64.3) mU I^-1, p < 0.05). There was no difference in plasma prorenin concentration between patients without and with microalbuminuria and between patients without and with background retinopathy. Plasma renin concentration, both when supine and upright, was similar in control subjects, in patients without complications, and in patients with varying degrees of diabetic microangiopathy. Plasma aldosterone was suppressed in patients without complications in comparison to control subjects (74 (58–95) vs 167 (140–199) ng I^-1, p < 0.001) and was also suppressed in patients with microvascular disease. Plasma potassium was significantly higher in patients than in control subjects (mean ± standard deviation: 4.10±0.36 vs 3.89±0.26 mmol I^-1; p < 0.001) and plasma sodium was significantly lower (138 ± 4 vs 140 ± 2 mmol I^-1; p < 0.001). We conclude that plasma prorenin is not a useful early marker for diabetic microvascular disease. Despite apparently normal plasma renin concentrations, plasma aldosterone is suppressed in insulin-dependent diabetic patients.     

Role of plasma and urinary endothelin-1 in early diabetic and hypertensive nephropathy

To evaluate the role of circulating and renal endothelin-1 (ET-1) in early diabetic nephropathy, plasma ET-1 levels and urinary ET-1 excretion were evaluated in lean, normotensive patients affected by non–insulin-dependent diabetes (NIDDM) either with (n = 9, NIDDM+) or without microalbuminuria (n = 18, NIDDM−); in never-treated, lean, essential hypertensive patients with (n = 12, EH+) or without microalbuminuria (n = 10, EH−); and in healthy volunteers (n = 12). Results showed higher plasma ET-1 levels in NIDDM+ (1.97 ± 0.58 pg/mL) than in NIDDM− (1.59 ± 0.14 pg/mL, P = .013), EH+ (1.40 ± 0.21 pg/mL, P = .005), EH− (0.91 ± 0.19 pg/mL, P < .0001), and controls (0.60 ± 0.10 pg/mL, P < .0001). The circulating ET-1 concentration was also higher in EH+ than EH− and controls (P < .0001).Urinary ET-1 excretion did not differ (P = .387, NS) between NIDDM+ (48.5 ± 20.1 pg/min) and NIDDM− (40.9 ± 21.6 pg/min), but was significantly reduced (P < .0001) in both groups compared with controls (70.0 ± 15.5 pg/min). Similar findings were observed in hypertensive subgroups. No correlations were found between urinary ET-1 and other variables, including plasma ET-1 levels, in all groups.In conclusion, NIDDM+ is accompanied by a significant increase in plasma ET-1 levels. A significant elevation of circulating ET-1 concentration was evident also in NIDDM−, suggesting that early abnormalities of ET-1 production might precede the microalbuminuric phase of diabetes-related renal damage.     

Effectiveness of Weekly Percutaneous Maxacalcitol Injection Therapy in Patients With Secondary Hyperparathyroidism

Percutaneous injection therapy with vitamin D has been applied in the treatment of hyperparathyroidism (HPT); however, the application of percutaneous injection therapy with vitamin D lacks established guidelines regarding the volume of injected solution and the frequency of injection. We have developed an outpatient treatment regimen using percutaneous maxacalcitol injection therapy (PMIT) on a weekly basis for 4–6 weeks following dialysis without major complications. Intact parathyroid hormone decreased from 797 ± 178 pg/mL to 253 ± 25 pg/mL, and the parathyroid gland volume initially increased during the first week, but thereafter, it gradually decreased with weekly PMIT (wPMIT). Finally, the parathyroid gland volume decreased from 1.27 ± 1.06 cm³ to 0.24 ± 0.15 cm³ after wPMIT. The benefits of our method were confirmed on weekly ultrasonographic examinations, which detailed the gradual reduction in gland size following an initial increase after the first injection. Therefore, we conclude that our carefully implemented PMIT method would be an effective treatment against refractory secondary HPT.     

COMPARISON OF THE PHARMACOKINETICS IN MAN OF TWO SYNTHETIC ACTH ANALOGES: a1–24 AND SUBSTITUTED β1–18 ACTH.

The synthetic substituted corticotrophin analogue, a^1–18 ACTH, was given intravenously or subcutaneously to thirteen human volunteers in whom endogenous secretion of ACTH had been suppressed with dexamethasone. Plasma levels of a^1–18 ACTH over the succeeding 12–24 h were determined by radioimmunoassay and bioassy, together with the fluorometric corticosteroid responses. The plasma disappearance rate of a^1–18 ACTH was compared with that of the corticotrophin fragment, a^1–24 ACTH (tetracosactrin, Synacthen), in both unmodified and depot forms. Plasma levels of a^1–18 ACTH were higher and were detectable for longer after intravenous rather than subcutaneous administration. The higher levels were associated with greater and more prologed corticosteroid responses. In addition, the corticosteroid response to the intravenous injection of 1 mg of a^1–18 was greater and more prolonged than the response to the intravenous injection of the same dose of a^1–24 ACTH. The plasma levels of immunoreactive a^1–24 ACTH were not detectable for more than 4 h after this dose. After the intramuscular administration of 1 mg of the depot preparation, however, detectable plasma levels persisted for 12 h. It is concluded that the brief corticotrophic activity of unmodified a^1–24 ACTH is due mainly to its rapid clearance from the circulation. There was no significant dissociation between the disappearance rates of immuno- and bio-active a^1–18 ACTH. This contrasted with a^1–24 ACTH whose bioactivity disappeared from plasma significantly faster than immunoreactivity. This difference probably reflects the greater stability of a^1-18 ACTH In the circulation and this in turn accounts, in part at least, for its prolonged corticotrophic activity. In a separate study the peptides were given intranasally through special applicators to eleven dexamethasone suppressed volunteers. The plasma levels of a^1–18 ACTH after a 1 mg dose were lower than when given by other routes but the corteroid response was unaltered. The corticosteroid response to a 1 mg dose of intranasal a^1–24 ACTH was brief and similar to that which followed an intavenous or subcutaneous injection; it was not significantly prolonged if 5 mg was given. It is concluded that intranasal a^1–24 ACTH is unlikely to be of value but itranasal a^1–18ACTH may be therapeutically useful.     

Plasma melatonin in the trout: day-night change demonstrated by radioimmunoassay

A melatonin radioimmunoassay technique, using a ¹²⁵I-labelled melatonin analog as the radiolabel, has been validated for rainbow trout (Salmo gairdneri). It was demonstrated that a dilution series of extracted trout plasma melatonin and a melatonin/PBS gel standard were parallel along a logit-transformed curve. Melatonin extracted from trout plasma was shown to comigrate with [³H]melatonin. The RIA procedure did not differentiate between endogenous trout melatonin and [³H]melatonin added to the same sample. Melatonin levels in plasma from trout anesthetized with MS-222 were not different from those found in plasma from trout killed by decapitation without anesthesia. Melatonin levels were high during the night (152.6 ± 15.8 pg of melatonin/ml of plasma) and low during the day (81.2 ± 19.3 pg of melatonin/ml of plasma).     

Serum neutrophil gelatinase-associated lipocalin concentration reflects severity of coronary artery disease in patients without heart failure and chronic kidney disease

Serum neutrophil gelatinase-associated lipocalin (NGAL) is recognized as a useful biomarker for acute kidney injury. Recently, elevated NGAL levels were reported in patients with heart failure and cardiac events, but the association between serum NGAL and severity of coronary artery disease (CAD) has not been investigated adequately. This study aimed to evaluate the association between serum NGAL concentration and CAD severity in patients without heart failure and chronic kidney disease. Two-hundred thirteen patients [mean age: 66.2 ± 9.2 (SD)] without heart failure and chronic kidney disease (estimated glomerular filtration rate >60 mL/min/1.73 m²) who underwent coronary angiography were retrospectively analyzed using the SYNTAX score. The mean concentration of serum NGAL was 134.3 ± 111.3 ng/mL. A statistically significant correlation was observed between serum NGAL levels and the SYNTAX score (R = 0.18, P = 0.0091). Multivariable analysis also showed elevated serum NGAL as an independent risk factor for a high SYNTAX score (P < 0.01). Moreover, we evaluated the association of serum NGAL and brain natriuretic peptide (BNP) with the SYNTAX score. Patients with high levels of serum NGAL (>100 ng/mL) and high levels of BNP (>25 pg/mL) had a higher SYNTAX score (low–low vs. high–high: 13.8 ± 13.4 vs. 20.8 ± 18.9, P < 0.05). Serum NGAL levels were positively and significantly associated with CAD severity, and the evaluation of both serum NGAL and BNP was useful for predicting CAD in patients without renal dysfunction and heart failure. Serum NGAL might be a biomarker for CAD severity.     

Adrenocortical (interrenal) responses to hypophysectomy and adenohypophysial hormones in the teleost Poecilia latipinna.

This work investigates the effects of hypophysectomy and replacement treatment with mammalian pituitary preparations (ACTH, TSH, prolactin, growth hormone, alpha-MSH) and cortisol and thyroxine, on the structure and function of the interrenal in the teleost Poecilia latipinna.In long-term (3–4 weeks) experiments, histological studies showed that hypophysectomy induced involution of the interrenal, which was prevented by treatment with ACTH. TSH also opposed this interrenal involution, but it was not as strongly mitogenic as ACTH. MSH, prolactin, growth hormone, and thyroxine had no effect on the involuted interrenal of hypophysectomized fish. Hypophysectomy also resulted in hypertrophy of the liver, elevated hepatic glycogen concentrations, and a reduced number of circulating leucocytes. All these changes were prevented by ACTH and cortisol, both of which also exacerbated the weight loss that followed pituitary ablation. MSH was not tested on leucocyte count, but it had no effect on liver weight, liver glycogen, and body weight loss. Both TSH and thyroxine increased the leucocyte count, and in addition thyroxine reduced liver weight and exacerbated body weight loss. Prolactin at high dose reduced liver weight, but did not affect liver glycogen and the leucocyte count, while at the highest dose it ameliorated body weight loss. Growth hormone at high dose reduced liver weight, but had no action on liver glycogen, leucocyte count, and body weight loss. Thus, only TSH seems able to mimic the effects of ACTH on interrenal structure. Its stimulatory effect on circulating leucocytes could be thyroid-mediated, since thyroxine has the same effect in the absence of any action on interrenal morphology. The actions of growth hormone and prolactin on liver weight would appear to be direct.In short-term (30 min) tests on hypophysectomized fish, ACTH, prolactin, TSH, growth hormone (porcine and human), and alpha-MSH all elevated plasma cortisol levels, reduced to near-zero by hypophysectomy 48 hr previously. Bovine serum albumin did not elevate plasma cortisol levels.The data are discussed bearing in mind the possibility of other pituitary hormones mimicking the actions of teleostean ACTH, on the one hand, and, on the other hand, the possibility of minute contamination of the hormone preparations with ACTH. This second possibility cannot be discounted in considering the cortisol-elevating properties of all the hormone preparations used in the short-term tests, but there are no compelling reasons for accepting it as explanation of the ability of TSH preparations to maintain interrenal morphology.The findings emphasize the difficulties inherent in using mammalian hormone preparations to deputise for fish pituitary hormones.