17 research outputs found
Current concepts on amphetamine abuse : proceedings of a workshop, Duke University Medical Center, June 5-6, 1970 /
Includes bibliographical references.Mode of access: Internet
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Pharmacokinetics of growth hormone secretion in humans induced by growth hormone releasing hormone
This investigation compares the age- and sex-related changes in growth hormone (GH) response to growth hormone releasing hormone (GHRH) in normal subjects using an appropriate pharmacokinetic model. Twenty-five subjects (14 males and 11 females) aged 23–89 yr received a single intravenous bolus dose (1 μg/kg) of GHRH-40 solution. Plasma GH concentration-time profiles are best characterized by a biexponential equation (or one-compartment model) with first-order release and disappearance rates and an equilibration lag time. The harmonic mean release rate half-life is similar for both sexes (males: 12.6 min vs. females: 11.4 min) but significantly different across age groups (23–35 yr: 7.2 min vs. 50–89 yr: 16.8 min). The mean disappearance rate half-life and GHRH-equilibration time lag for females (33.6 and 20.4 min, respectively) and the higher age group subjects (32.4 and 21.6 min, respectively) are significantly longer than those of males (22.8 and 9 min, respectively) and the lower age-group subjects (21.6 and 8.4 min, respectively). The mean metabolic clearance rate of GH is significantly lower (p<0.02) for females than for males (3.1 vs. 4.83 ml/hr·m
2). However, the production rate and the amount of GH released by the pituitary for our subjects appear to be very similar for both males (8.7 μg/hr·m
2 and 4.65 μg/m
2) and females (9.33 μg/hr·m
2 and 5.11 μg/m
2)
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