Age-related change in plasma concentration of 7B2 (a novel pituitary polypeptide) in normal humans

Life Sciences ◽  
1987 ◽  
Vol 41 (8) ◽  
pp. 977-981 ◽  
Author(s):  
Shoichi Natori ◽  
Haruo Iguchi ◽  
Hajime Nawata ◽  
Ken-ichi Kato ◽  
Hiroshi Ibayashi ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Age Related ◽  
Normal Humans

In vivo acute testicular testosterone response to injection of luteinizing hormone in the rat fetus

1993 ◽  
Vol 128 (3) ◽  
pp. 268-273 ◽  
Author(s):  
René Habert
Keyword(s):  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Leydig Cells ◽  
Time Dependent ◽  
Fetal Life ◽  
Dependent Manner ◽  
Adult Rats ◽  
Rat Fetus ◽  
Age Related

The acute in vivo testosterone response to LH stimulation and its change during late fetal life were determined in the rat. In 18.5-day-old fetuses, testicular testosterone content was increased in a dose-and time-dependent manner after fetal subcutaneous LH injection. The maximum response was small: the testicular content and plasma concentration were increased by 200% and 2 50% over basal values respectively, while they were increased 1100% and 1200% in adult rats. Similarly, comparable low responses were obtained after subcutaneously injecting the fetuses with human chorionic gonadotropin (hCG) and after injecting LH into the vitelline vein. Between days 18.5 and 21.5 of fetal life, the testosterone levels in the testis and plasma of uninjected or PBS-injected fetuses decreased and were comparable in both groups. In maximally LH-stimulated fetuses, the testicular content did not change with age, and plasma concentration was lower on day 21.5 than on day 18.5. Since the number of Leydig cells increases 1.5 to 2-fold between days 18.5 and 21.5, these results show an age-related decrease in basal and maximally LH-stimulated in vivo testosterone secretions per Leydig cell during late fetal life.

Relationship between vasopressin and renal concentrating ability in aging rats

1992 ◽  
Vol 262 (5) ◽  
pp. R826-R833 ◽  
Author(s):  
G. Geelen ◽  
B. Corman
Keyword(s):  
Plasma Concentration ◽  
Urinary Excretion ◽  
Arginine Vasopressin ◽  
Age Groups ◽  
Urine Osmolality ◽  
Similar Increase ◽  
Aging Rats ◽  
Inappropriate Secretion ◽  
Age Related ◽  
The Relationship

The relationship between arginine vasopressin (AVP) secretion and the age-related change in renal concentrating ability was studied in 10-, 20-, and 30-mo-old conscious rats. In control condition, urine osmolality (Uosmol) was 2,358 +/- 99, 1,919 +/- 87, and 1,135 +/- 173 mosmol/kgH2O (mean +/- SE) and the corresponding plasma AVP concentration 3.1 +/- 1.2, 2.8 +/- 0.7, and 3.3 +/- 0.7 pg/ml at 10, 20, and 30 mo. Urinary AVP excretion and AVP content in the hypothalamus were comparable in the 3 age groups, while the basal AVP pituitary content was significantly higher at 10 than at 20 or 30 mo. Three days of dehydration induced 1) a similar increase in plasma concentration and urinary excretion of AVP in the 3 groups, even though the maximal Uosmol reached by the oldest animals was significantly reduced (3,988 +/- 218, 3,652 +/- 273, and 2,826 +/- 197 mosmol/kgH2O at 10, 20, and 30 mo, respectively) and 2) a similar AVP depletion of the pituitary at 10, 20, and 30 mo and an increase of the AVP content in the hypothalamus at 10 mo but not at 20 and 30 mo. These results suggest that the decrease in renal concentrating ability reported in aging rats is not due to an inappropriate secretion of AVP along the hypothalamo-neurohypophysial axis but is rather related to an impaired responsiveness of the kidney to the antidiuretic hormone.

Opioid pharmacodynamics in neonatal dogs: differences between morphine and fentanyl

1995 ◽  
Vol 79 (5) ◽  
pp. 1519-1524 ◽  
Author(s):  
P. Bragg ◽  
M. S. Zwass ◽  
M. Lau ◽  
D. M. Fisher
Keyword(s):  
Steady State ◽  
Plasma Concentration ◽  
Minute Ventilation ◽  
Pharmacodynamic Model ◽  
Effect Compartment ◽  
Laboratory Studies ◽  
Age Related ◽  
Ventilatory Effects ◽  
Arterial Plasma ◽  
Related Increase

Clinical experience and laboratory studies suggest that neonates are more sensitive than adults to the ventilatory depressant effects of morphine. Similar sensitivity has been cited, but not demonstrated, for fentanyl. To examine this issue, we determined ventilatory pharmacodynamics of morphine and fentanyl in 28 dogs aged 2–35 days. During isohypercapnia, morphine or fentanyl was infused to depress minute ventilation by > 50% and arterial plasma opioid concentrations were measured. For each drug, an effect compartment pharmacodynamic model was fit to the values for minute ventilation to determine the steady-state opioid plasma concentration depressing ventilation by 50% (C50) and the rate constant for equilibration between plasma concentration and effect (keo). For morphine, there was a marked age-related increase in C50 but no change in keo. For fentanyl, there was a small maturational increase in C50 and no change in keo. We conclude that there are marked maturational changes in the ventilatory depressant effects of morphine resulting from maturational changes in sensitivity rather than in equilibration. Maturational changes in the ventilatory effects of fentanyl are much smaller in magnitude than those for morphine.

Thyroxine concentration in maternal and foetal plasma during pregnancy in Australian feral goats

1988 ◽  
Vol 110 (1) ◽  
pp. 25-30 ◽  
Author(s):  
B. J. McDonald ◽  
D. C. Stocks ◽  
J. A. Connell ◽  
W. A. Hoey
Keyword(s):  
Plasma Concentration ◽  
Thyroid Function ◽  
Gestational Age ◽  
Free Thyroxine ◽  
Foetal Circulation ◽  
Age Related ◽  
Maternal Thyroid ◽  
Age Related Changes

SummaryGestational age-related changes in plasma free thyroxine (FT4) concentration in maternal and foetal goats were determined for 65–140 days of pregnancy. The placental permeability to maternal thyroxine (T4) and iodine (I) during the last trimester of pregnancy was evaluated.The presence of T4 in foetal circulation at 65 days' gestation, the absence of a significant correlation between maternal and foetal levels and the absence of any transplacental diffusion of 125I–T4 showed autonomous foetal thyroid function during pregnancy in goats. Significantly low maternal FT4 was measured at 95 and 110 days' gestation (32·7 and 31·5 pmol/1 respectively). Plasma concentration increased to 48·6 pmol/1 at day 125 then fell before parturition to a level similar to that of non-pregnant goats (41·9 pmol/1). In contrast, foetal FT4 increased with gestational age to 110 and 125 days when levels of 64·0 and 59·1 pmol/1 respectively were greater than those at all other ages, suggesting that the foetal hypothalamic-pituitary-thyroid is functioning at a higher rate than the maternal system around this time. This was supported by increased foetal thyroid affinity for I when compared with the maternal thyroid at 110–140 days' gestation.A significant cubic relationship between foetal FT4 and gestational age was established.

scholarly journals P85 Prediction of raltegravir plasma concentration in HIV paediatric patients using physiologically-based pharmacokinetic model

2019 ◽  
Vol 104 (6) ◽  
pp. e52.2-e53
Author(s):  
F Salem ◽  
K Abduljalil ◽  
T Johnson
Keyword(s):  
Plasma Concentration ◽  
Geometric Mean ◽  
Time Profile ◽  
Metabolic Enzyme ◽  
List Type ◽  
Physiologically Based Pharmacokinetic ◽  
Concentration Time ◽  
Paediatric Patients ◽  
Age Related ◽  
Rate Of Absorption

BackgroundRaltegravir is a drug used to treat patients with HIV infection. Understanding the disposition kinetics including the ontogeny of the major metabolic enzyme (UGT1A1) is important in prediction of raltaeravir pharmacokinetics in paediatric patients.MethodsSim-Raltegravir compound file in Simcyp simulator version 18 was used to predict pharmacokinetics in paediatric subjects aged 4 weeks to 6 months, 0.5 to 2, 2 to 6 and 6 to 12 years. Details of trial design were matched as closely as possible with a clinical study.1 Rate of absorption and variability in first order absorption model within Simcyp were set to the reported values. Predicted plasma concentration time profiles with 5th and 95th percentile were compared with observations.ResultsThe predicted vs. observed geometric mean area under plasma concentration-time profile of raltegravir was 18.4 vs. 22.3 µM.h in subjects 4 weeks to 6 months and 16.5 vs. 19.8 µM.h in those 0.5 to 2 years old. In 2 to 6 and 6 to 12 year olds around 80% and 85% of observed data were within 5th and 95th percentile of the predictions.ConclusionThe results show that the UGT1A1 ontogeny profile in the Simcyp version 18 adequately addressed age-related differences in pharmacokinetics of raltegravir.ReferenceRizk, M., et al, J Clin Pharmacol 2015; 55(7):748–56Disclosure(s)Nothing to disclose

scholarly journals Pharmacokinetics and Safety of a New Parenteral Carbapenem Antibiotic, Biapenem (L-627), in Elderly Subjects

1998 ◽  
Vol 42 (6) ◽  
pp. 1433-1436 ◽  
Author(s):  
Osamu Kozawa ◽  
Toshihiko Uematsu ◽  
Hiroyuki Matsuno ◽  
Masayuki Niwa ◽  
Yoshiharu Takiguchi ◽  
...  
Keyword(s):  
Renal Function ◽  
Plasma Concentration ◽  
Elderly Subjects ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Healthy Elderly ◽  
Age Related ◽  
Group A ◽  
Group B ◽  
Carbapenem Antibiotic

ABSTRACT The pharmacokinetics and tolerability of a new parenteral carbapenem antibiotic, biapenem (L-627), were studied in healthy elderly volunteers aged 65 to 74 years (71.6 ± 2.7 years [mean ± standard deviation], n = 5; group B) and ≥75 years (77.8 ± 1.9 years, n = 5; group C), following single intravenous doses (300 and 600 mg), and compared with those of healthy young male volunteers aged 20 to 29 years (23.0 ± 3.5 years, n = 5; group A). The agent was well tolerated in all three age groups. Serial blood and urine samples were analyzed for biapenem to obtain key pharmacokinetic parameters by both two-compartment model-dependent and -independent methods. The maximum plasma concentration and area under plasma concentration-versus-time curve (AUC) increased in proportion to the dose in all three groups. Statistically significant age-related effects for AUC, total body clearance, and renal clearance (CLR) were found, while elimination half-life (t 1/2β) and percent cumulative recovery from urine of unchanged drug (% UR) remained unaltered (t 1/2β, 1.51 ± 0.42 [300 mg] and 2.19 ± 0.64 [600 mg] h [group A], 1.82 ± 1.14 and 1.45 ± 0.36 h [group B], and 1.75 ± 0.23 and 1.59 ± 0.18 h [group C]; %UR, 52.6% ± 3.0% [300 mg] and 53.1% ± 5.1% [600 mg] [group A], 46.7% ± 7.4% and 53.0% ± 4.8% [group B], and 50.1% ± 5.2% and 47.1% ± 7.6% [group C]). A significant linear correlation was observed between the CLR of biapenem and creatinine clearance at the dose of 300 mg but not at 600 mg. The steady-state volume of distribution tended to be decreased with age, although not significantly. Therefore, the age-related changes in parameters of biapenem described above were attributable to the combination of decreased lean body mass and lowered renal function of the elderly subjects. However, the magnitude of those changes does not necessitate dosage adjustment in elderly patients with normal renal function for their age.

Epinephrine and Norepinephrine Concentrations in Plasma of Humans and Rats

1957 ◽  
Vol 3 (4) ◽  
pp. 239-248 ◽  
Author(s):  
Irving Gray ◽  
James G Young
Keyword(s):  
Plasma Concentration ◽  
Men And Women ◽  
Average Value ◽  
Normal Humans

Abstract The Weil-Malherbe and Bone method for the analysis of the plasma concentration of epinephrine and norepinephrine has been modified and used to determine the plasma concentration in normal humans. The average value for epinephrine in the plasma of men in this series was less than 0.11 µg./L.; for women it was 0.47 µg./L. The average value for norepinephrine in men was 3.4 µg./L. and in women it was 4.9 µg./L. The differences between the concentrations in men and women are significant, P<0.001 and P<0.01 for epinephrine and norepinephrine, respectively. Evidence has been presented to indicate the specificity of the method. Reproducibility and recovery data have been given.

Age-related reduction in 99Tcm-DTPA alveolar-capillary clearance in normal humans

1996 ◽  
Vol 17 (11) ◽  
pp. 971-974 ◽  
Author(s):  
F. J.H.N. BRAGA ◽  
J. C. MANÇO ◽  
J. F. SOUZA ◽  
E. FERRIOLI ◽  
J. DE ANDRADE ◽  
...  
Keyword(s):  
Age Related ◽  
Normal Humans ◽  
Capillary Clearance ◽  
Alveolar Capillary

Spindle shaped bodies in foveolar cones of the baboon retina

1989 ◽  
Vol 47 ◽  
pp. 960-961
Author(s):  
W. Krebs ◽  
I. Krebs
Keyword(s):  
Cross Sections ◽  
Inclusion Bodies ◽  
Photoreceptor Cells ◽  
Papio Anubis ◽  
Retinal Photoreceptor ◽  
Age Related ◽  
Cone Cells ◽  
Membrane Bound ◽  
Oriented Parallel ◽  
Shaped Inclusion

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).

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