Involvement of inhibin in the regulation of FSH secretion in prepubertal bulls

1993 ◽  
Vol 137 (1) ◽  
pp. 15-19 ◽  
Author(s):  
H. Kaneko ◽  
M. Yoshida ◽  
Y. Hara ◽  
K. Taya ◽  
K. Araki ◽  
...  
Keyword(s):  
Strong Evidence ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Physiological Importance ◽  
Control Serum ◽  
Inhibitory Regulation

ABSTRACT To investigate the physiological importance of inhibin in the regulation of FSH secretion in prepubertal bulls, animals (6-month-old) were passively immunized against inhibin. Five animals were given an i.v. bolus injection of 50 ml inhibin antiserum raised against bovine 32 kDa inhibin in a castrated male goat, and four bulls were given the same amount of castrated male goat serum (control serum) as controls. Treatment with the inhibin antiserum resulted in a marked increase (P < 0·01) in plasma concentrations of FSH within 12 h compared with control animals, and FSH levels in immunized animals remained high until 168 h after the injection. Concentrations of plasma LH and testosterone in the immunized animals were not different from those in the control animals. The present findings provide strong evidence that inhibin plays an important role in the inhibitory regulation of FSH secretion in prepubertal bulls. Journal of Endocrinology (1993) 137, 15–19

Evidence that inhibin is an important factor in the regulation of FSH secretion during the mid-luteal phase in cows

1993 ◽  
Vol 136 (1) ◽  
pp. 35-41 ◽  
Author(s):  
H. Kaneko ◽  
Y. Nakanishi ◽  
K. Taya ◽  
H. Kishi ◽  
G. Watanabe ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Plasma Concentrations ◽  
Control Level ◽  
Follicular Development ◽  
Abrupt Decrease ◽  
Control Value ◽  
Physiological Importance ◽  
Control Serum ◽  
High Concentrations ◽  
Inhibitory Regulation

ABSTRACT To investigate the physiological importance of inhibin in the regulation of FSH secretion in cows, seven cyclic cows were treated with an inhibin antiserum raised against bovine 32 kDa inhibin in a castrated goat. The same animals treated with a castrated goat serum (control serum) served as controls. On day 12 of the oestrous cycle (day 0 = day of oestrus), four of seven cows were injected with 100 ml inhibin antiserum first, and the remaining three cows with 100 ml control serum first. Twelve days after the second oestrus following the first serum injection (42–46 days after the first serum injection), the former four cows were injected with control serum and the latter three with inhibin antiserum. Follicular development after the injections of control serum or inhibin antiserum was assessed by daily ultrasonographic examination. Treatment with inhibin antiserum resulted in a marked increase (P < 0·01) in plasma concentrations of FSH and oestradiol-17β but not LH or progesterone, compared with those after treatment with control serum. Plasma concentrations of FSH increased significantly (P < 0·01) at 8 h after injection of antiinhibin serum when compared with the control value. Concentrations of FSH in the plasma remained high for 72 h, then declined to the control level by 84 h, concomitant with an abrupt decrease in the titre of free inhibin antibody in the plasma. High concentrations of oestradiol-17β were observed between 36 and 96 h after treatment. Treatment with inhibin antiserum markedly increased the number of small (≥ 4 < 7 mm in diameter), medium (≥ 7 < 10 mm) and large (≥ 10 mm) follicles by 48, 72 and 96 h after treatment when compared with the value before treatment. The number of large follicles returned to the pretreatment value at 168 h, whereas the number of small and medium follicles remained increased. The present results provide strong evidence that inhibin is an important factor in the inhibitory regulation of FSH secretion during the mid-luteal phase of cows, and demonstrate that an increase in endogenous FSH secretion after immunoneutralization of circulating inhibin stimulates the rapid growth of a large number of follicles. Journal of Endocrinology (1993) 136, 35–41

Hepatic removal of two fractions of indocyanine green after bolus injection in anesthetized pigs

1994 ◽  
Vol 266 (6) ◽  
pp. G1108-G1122 ◽  
Author(s):  
P. Ott ◽  
S. Keiding ◽  
A. H. Johnsen ◽  
L. Bass
Keyword(s):  
Indocyanine Green ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Hepatic Uptake ◽  
Hepatic Extraction ◽  
First Order ◽  
Extraction Fraction ◽  
Disappearance Curve ◽  
Detailed Mathematical Analysis ◽  
Plasma Disappearance Curve

In the anesthetized pig, we studied the kinetics after intravenous bolus injection of two fractions of indocyanine green (ICG): the genuine ICGg (95-99% of total) and a degradation product, ICGdp (1-5%). Plasma concentrations were followed in the carotid artery and a hepatic vein. ICGg disappearance curves (n = 7) were biexponential with rate constants alpha = 0.189 +/- 0.021 min-1 and beta = 0.0356 +/- 0.0061 min-1. The hepatic extraction fraction was constant with time. A detailed mathematical analysis showed this to be in disagreement with the conventional assumption that the biexponential plasma disappearance curve is a result of backflux from the liver storage to plasma. In contrast, our observations were predicted by an alternative model assuming temporary extrahepatic, extravasal redistribution during first-order, one-way hepatic uptake. Nevertheless, when a large bolus of sulfobromophthalein (BSP) was injected 20 min after ICG, a net backflux of ICG could be demonstrated, presumably due to countertransport. Thus a sufficient description of ICGg kinetics must include the complex kinetic behavior of the hepatic membrane carrier involved. Mass spectrometry suggested that ICGdp is formed by two ICGg molecules. Plasma elimination of ICGdp was slower (alpha = 0.0094 +/- 0.0007 min-1). Analysis of the bile after bolus injection (n = 2) of ICGdp revealed two possible metabolites of ICGdp that were not found in urine. Since BSP injection did not alter the ICGdp disappearance curve, ICGdp is probably not taken up by the same hepatic membrane carrier as ICGg.

Cardiovascular effects and cardiopulmonary plasma gradients following intravenous infusion of neuropeptide Y in humans: negative dromotropic effect on atrioventricular node conduction

2002 ◽  
Vol 103 (6) ◽  
pp. 535-542 ◽  
Author(s):  
Bengt ULLMAN ◽  
John PERNOW ◽  
Jan M. LUNDBERG ◽  
Hans ÅSTRÖM ◽  
Lennart BERGFELDT
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Neuropeptide Y ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Systemic Blood Pressure ◽  
Cardiac Conduction ◽  
Systemic Blood ◽  
Av Node

Neuropeptide Y (NPY) is co-released with noradrenaline from sympathetic nerves, has a strong vasoconstrictive action, and causes an attenuation of parasympathetic action in animal experiments. The plasma level of NPY is greatly elevated in patients with congestive heart failure, but the clinical relevance of this finding is unclear. Central haemodynamic effects, cardiac conduction system electrophysiology and coronary sinus blood flow were therefore studied in two sets of experiments, each carried out on seven healthy men. In the first series, NPY was given intravenously at doses of 3, 10 and 30pmolμmin-1μkg-1, and in the second it was given as a bolus injection of 90, 200 or 900pmol/kg, which resulted in plasma concentrations similar to those seen in heart failure patients. During continuous infusion of NPY, systemic blood pressure increased slightly, but myocardial perfusion, cardiac output, pulmonary arterial pressure, cardiac conduction intervals and atrioventricular (AV) node functional measures remained unchanged. In contrast, the bolus injection of NPY evoked prolongation and block (in four out of seven subjects) of AV node conduction, but did not affect haemodynamic variables, apart from a minor increase in systemic blood pressure. Impaired AV node conduction is a novel observation, which might reflect a baroreceptor-mediated vagal reflex, or–more likely–an NPY-induced direct negative dromotropic effect, caused by a reduction of the L-type calcium current as observed in vitro, or a combination of the two.

Induction of superovulation by immunoneutralization of endogenous inhibin through the increase in the secretion of follicle-stimulating hormone in the cyclic golden hamster

1996 ◽  
Vol 151 (1) ◽  
pp. 65-75 ◽  
Author(s):  
H Kishi ◽  
T Okada ◽  
M Otsuka ◽  
G Watanabe ◽  
K Taya ◽  
...  
Keyword(s):  
Plasma Levels ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Daily Injection ◽  
Important Indicator ◽  
The Third ◽  
Progesterone Secretion ◽  
Control Serum ◽  
Species Specific ◽  
Specific Number

Abstract The present study was conducted to study the effect of immunoneutralization against endogenous inhibin on FSH, LH, oestradiol-17β and progesterone secretion and to investigate the effect of removal of endogenous inhibin on subsequent follicular development in the hamster. After treatment with anti-inhibin serum (inhibin-AS) at 1100 h on day 2 of the oestrous cycle (day 1=day of ovulation), a marked increase in plasma levels of FSH and a slight increase in plasma levels of LH were noted and pituitary contents of FSH, but not LH, were also increased. In the group treated with inhibin-AS, superovulation occurred on day 1 of the following cycle. Plasma levels of oestradiol-17β markedly increased with the increase in the number of ovulations induced by human chorionic gonadotrophin (hCG) as compared with those in control animals. In the second cycle, plasma concentrations and pituitary contents of FSH in the animals given 200 μl inhibin-AS still showed high values as compared with those in the animals treated with control serum, although superovulation did not occur on day 1 of the third cycle. Plasma concentrations and pituitary contents of LH in the hamster given 200 μl inhibin-AS tended to decrease as compared with those in control animals during the second cycle. Plasma concentrations of oestradiol-17β in the animals treated with 200 μl inhibin-AS changed in a similar way to controls. A marked increase in plasma concentrations of progesterone was noted on days 1 and 2 of the second cycle in the group receiving inhibin-AS. The twice daily injection of 1 IU hCG during the second cycle to the animals given 200 μl inhibin-AS induced superovulation on day 1 of the third cycle. These results indicate that circulating inhibin may be an important indicator of the number of developing follicles and may maintain the species-specific number of developing follicles through suppression of FSH secretion in the cyclic hamster. They also suggest that high levels of inhibin slightly suppress plasma levels of LH, indicating that plasma LH may also regulate follicular development in the cyclic hamster. Journal of Endocrinology (1996) 151, 65–75

Metabolic clearance rate in sheep of a met-enkephalin analogue estimated by radioimmunoassay

1982 ◽  
Vol 93 (3) ◽  
pp. 427-433 ◽  
Author(s):  
J. E. Bolton ◽  
J. H. Livesey ◽  
R. A. Donald
Keyword(s):  
Clearance Rate ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Volume Of Distribution ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Time Intervals ◽  
Naturally Occurring ◽  
Specific Radioimmunoassay ◽  
The Mean

A sensitive and specific radioimmunoassay developed for measuring the met-enkephalin analogue d-ala2-met(0)5-ol-enkephalin (DAMME) was used to study the pharmacokinetics of DAMME in the circulation of sheep. Plasma concentrations of DAMME were measured at varying time-intervals after an intravenous bolus injection or following a constant intravenous infusion of the analogue. The mean metabolic clearance rate of DAMME was 2·8 ml/min per kg, the mean circulating half-life was 52 min and the mean volume of distribution was 190 ml/kg. The longer circulating time of the analogue when compared with that of naturally occurring met-enkephalin would appear to explain its prolonged analgesic effect.

Regulation of plasma calcium and phosphate in calcitonin-infused rats.

1990 ◽  
Vol 259 (3) ◽  
pp. E370
Author(s):  
S Lausson ◽  
P Tracqui ◽  
L Toubiana ◽  
G Milhaud ◽  
A M Perault-Staub ◽  
...  
Keyword(s):  
Bolus Injection ◽  
Spontaneous Recovery ◽  
Plasma Concentrations ◽  
Constant Infusion ◽  
Daily Variations ◽  
Mineral Data ◽  
The Mean ◽  
Mean Differences ◽  
Mineral Concentrations

The effects of long-term constant infusion of moderate doses (2-32 ng/h) of salmon calcitonin (sCT) on plasma Ca (and its radionuclide 45Ca), Pi, Mg, and on endogenous rat CT (rCT) metabolism were investigated in the rat. Daily variations were included. 1) The plasma concentrations of Ca and Pi fell and that of Mg increased transiently during infusion, with the duration of responses (1-3 days) depending on the sCT dose. Rats infused with 8 ng/h sCT remained sensitive to CT after 7 and 14 days, as indicated by the effects of minipump removal and of a bolus injection of exogenous sCT on plasma mineral concentrations. 2) In contrast to control rats, the well-established daily variations in plasma Ca and Pi levels were no longer observed after 7 and 14 days of sCT infusion (8 ng/h), but normal variations persisted for plasma Mg, circulating rCT, rCT mRNA, and rCT thyroid content. 3) Statistical analysis of plasma mineral data, collected at five sequential times during days 7 and 14, showed that the means were not significantly different and that the daily variations were essentially identical on days 7 and 14 in control rats. In contrast, the variability of measurements for plasma Ca and Pi, but not for Mg, increased significantly between days 7 and 14 in infused rats, and the mean differences were significantly lower in infused rats on day 7 than in control rats. These results are consistent with a transitory loss of the daily variations for Ca and Pi (day 7) and the later (day 14) spontaneous recovery of some variations in these parameters, although the individuals remain unsynchronized.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Clinical Pharmacokinetics of Long-Term Infusion of Midazolam in Critically Ill Patients — Preliminary Results

1987 ◽  
Vol 15 (4) ◽  
pp. 440-444 ◽  
Author(s):  
M. S. C. Dirksen ◽  
T. B. Vree ◽  
J. J. Driessen
Keyword(s):  
Intensive Care ◽  
Status Epilepticus ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Prolonged Infusion ◽  
Main Metabolite ◽  
Clinical Pharmacokinetics ◽  
Intensive Care Patients ◽  
Elimination Half

Seven intensive care patients were sedated with prolonged infusion of midazolam. One patient received a continuous infusion of midazolam for the treatment of status epilepticus. A bolus injection of 5 mg was administered, followed by infusion of 4–14 mg/hour depending on the required level of sedation. The length of infusion varied between 80 and 360 hours. The plasma concentrations of the midazolam during infusion were between 500–1000 ng/ml. All the patients were adequately sedated. The plasma elimination half-life of midazolam and its main metabolite, 1-OH-midazolam glucuronide, after stopping the infusion varied from 4–12 hours.

scholarly journals Effects of Bolus Injection of 5-Fluorouracil on Steady-State Plasma Concentrations of 5-Fluorouracil in Japanese Patients with Advanced Colorectal Cancer

2011 ◽  
Vol 8 (5) ◽  
pp. 406-412 ◽  
Author(s):  
Takao Tamura ◽  
Akiko Kuwahara ◽  
Kaori Kadoyama ◽  
Motohiro Yamamori ◽  
Kohshi Nishiguchi ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Steady State ◽  
Bolus Injection ◽  
Advanced Colorectal Cancer ◽  
Plasma Concentrations ◽  
Japanese Patients ◽  
State Plasma

Serum half-life and in-vivo actions of recombinant bovine placental lactogen in the dairy cow

1992 ◽  
Vol 132 (2) ◽  
pp. 185-193 ◽  
Author(s):  
J. C. Byatt ◽  
P. J. Eppard ◽  
J. J. Veenhuizen ◽  
R. H. Sorbet ◽  
F. C. Buonomo ◽  
...  
Keyword(s):  
Half Life ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
Metabolic Effects ◽  
Placental Lactogen ◽  
Blood Samples ◽  
Igf I ◽  
Single Compartment Model

ABSTRACT The clearance rate of recombinant bovine placental lactogen (rbPL) from the blood serum of four lactating dairy cows was measured using a specific radioimmunoassay. Two animals were non-pregnant, while the other two were at approximately 120 days of gestation. The rbPL was administered as an i.v. bolus injection (4 mg total) via an indwelling jugular catheter. Blood samples were taken periodically for 180 min and assayed for rbPL. Analysis of the clearance curves for the bolus injection suggested a single-compartment model and a serum half-life of 7·25 min. In a second experiment with the same animals, following cessation of lactation, rbPL or bovine GH (bGH) were administered by s.c. injection (50 mg/day) for 5 consecutive days. Blood samples were taken twice per day during the treatment period and a 3-day pretreatment period. Samples were analysed for glucose, blood urea nitrogen (BUN), non-esterified fatty acids (NEFA), creatinine, insulin, insulin-like growth factor-I (IGF-I) and IGF-II, tri-iodothyronine (T3), progesterone and IGF-binding protein-2 (IGFBP-2) to determine whether rbPL mediates similar metabolic effects to those of bGH. Administration of bGH stimulated an increase in NEFA, glucose, T3 and insulin, whereas none of these variables was affected by rbPL. The plasma concentrations of IGF-I and IGF-II were both increased by treatment with rbPL but, to a lesser extent than occurred with bGH. Interestingly, BUN and IGFBP-2 concentrations were reduced equally by bGH and rbPL. These results suggest that rbPL does not necessarily act as a GH agonist but, rather, may have distinct effects on intermediary metabolism that could be mediated through another specific receptor. Journal of Endocrinology (1992) 132, 185–193

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