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S Quinn

Publications and source records attributed to S Quinn.

15 recordsLinked to original sources
PubMed1992

Growth hormone-binding proteins of human serum: developmental patterns in normal man.

The binding of GH by a low affinity binding protein (LA-BP) was measured from birth into adulthood and compared with binding of a high affinity binding protein (HA-BP) in human serum. Pooled serum samples for each year of age from birth to 16.5 yr were formed from 2500 separate samples and assayed for both binding proteins using a Sephadex chromatographic method. Individual samples in this age range and those from adults were assayed in a similar manner. Binding of [125I]GH was minimal by both binding proteins in cord blood (binding by LA-BP, 2.77 +/- 0.32%; binding by HA-BP, 2.58 +/- 0.35% mean +/- SEM). A 4-fold increase to maximal binding for LA-BP occurred by the age of 5 yr and remained relatively constant through adolescence, except for a transient decrease at puberty. From 16.5-20 yr of age, binding by LA-BP decreased to a level no greater than that seen at birth. Binding by the HA-BP, which increased 6- to 8-fold reached maximal binding between 23-25 yr of age. Binding by HA-BP did not decrease in adults between the ages of 20-30 yr. Whereas pregnancy increased LA-BP activity, GH binding by HA-BP was unaltered.

Adolescent↗
PubMed1991

The growth hormone-insulin-like growth factor I axis: studies in man during growth.

Several major differences are noted between males and females in their patterns of growth at puberty. Accelerated pubertal growth in both males and females depends upon the integrity of the GH-receptor system. In males, acceleration of growth results primarily from enhanced sensitivity of the GH-receptor-IGF I system to GH brought about by testosterone. Whether testosterone itself is responsible for this observation is still unclear. Perhaps the initial GH, IGF I peak present in males and absent in females occurs at the time when sleep-related rises of gonadotropins and testosterone begin just prior to puberty. Though the pygmy data certainly supports a relationship between testosterone and the GH-receptor-IGF I axis, the undisputed tall stature of eunuchs remains a puzzle. It is possible that the maturing male gonad secretes another growth factor and/or growth inhibitor in conjunction with testosterone and that it is this unidentified factor which modulates growth. At any rate, acceleration of growth in males results from sensitization or the GH-receptor-IGF I system while growth acceleration in females results almost solely from increased secretion of GH and not sensitization of the system.

Adolescent↗
PubMed1991

Hormone and receptor studies: relationship to linear growth in childhood and puberty.

Preliminary data suggested different patterns of hormonal control of linear growth in males and females. To better define these patterns, serum samples were collected from 75-125 boys and a similar number from girls for each year of age between 3-16 yr (n = 2416). Fewer samples were collected from 2-yr-olds, newborns, and adults (n = 151). Samples for each age were aliquoted, combined, and assayed for GH, GH-binding protein (GHBP), insulin-like growth factor-I, and testosterone. GHBP, expressed as a percentage of the [125I]GH bound, increased yearly in males and females, with no relationship to the secretion of sex hormones. The increase in binding of [125I]GH and, by inference, GH receptors occurred at a greater rate between the ages of 2-10 yr than between 10-16 yr (in terms of absolute binding, 1.2 +/- 0.11% vs. 0.38 +/- 0.04% yearly; P less than 0.001). In each age group, however, the increase in GHBP exhibited a strong positive correlation with linear height (r = 0.96-0.98 in males; r = 0.92-0.99 in females). Before puberty, GH and insulin-like growth factor-I concentrations were consistently greater in females. Between 10-16 yr of age, height velocity (centimeters of growth per yr) correlated strongly with GH in girls (r = 0.86), but did not correlate with GH in boys of a similar age (r = -0.13). The major pubertal growth spurt in males strongly correlated with a rise in serum testosterone concentration beginning at age 11 yr (r = 0.92). Small peaks of GH secretion before and after the major period of accelerated growth in males possibly prolonged the major growth phase, but did not initiate it.

Adolescent↗