Increased Gh Response to GHRH in Normal Tall Men

Abstract

The importance of growth hormone secretion to the growth of an individual raises the question of the role that the secretory capacity of this hormone may play in defining the variations of height within the population. To investigate this problem we studied the response of GH to GHRH in 20 normal tall (mean +/- SD height 190.8 +/- 2.4 cm, range 187-196 cm) adult males of the third decade and in 17 age-matched controls of average height (mean +/- SD height 173.8 +/- 1.6 cm, range 171-177 cm). Synthetic GHRH (1-29) NH2 (Kabi, Vitrum, Sweden) was administered at 0800 h after an overnight fast and blood was drawn for GH assay. In the tall subjects basal GH concentrations at -15 and 0 min were not significantly different from those of the controls. However, the tendency to higher basal GH levels and spontaneous peaks was evident in tall individuals. Only three basal GH values were below 1 micrograms/l (0.8-0.9 micrograms/l; 1 microgram/l = 2mU/l) in the tall individuals while 24 of 33 basal GH values in the controls ranged between 0.25 and 0.87 micrograms/l. At +15 and +30 min after GHRH the rise in GH was significantly greater in the tall subjects. Moreover, the integrated area under the response curves was significantly greater in the tall subjects than the controls (P less than 0.01). No differences in the mean serum testosterone and prolactin levels were found in the two groups. It is postulated that if this enhanced pituitary responsiveness is constant and chronic in tall individuals a definite relation of their stature to the GH secretion is to be anticipated.

Overnight Urinary Growth Hormone Measurement in the Diagnosis of Acromegaly

“…This finding is consistent with our observation that other variables related to body size, such as surface area, creatinine excretion rate, and sex, showed a weak but significant correlation with urinary GH on unilinear analysis. It is unclear from the present study whether the association between urinary GH and height is related to a tendency towards higher serum GH concentrations in taller subjects (Batrinos et al, 1989), or whether there is another association between body size and urinary GH excretion, the cause of which has yet to be determined. Correcting results for height produced minimal improvement in discrimination between controls and acromegalic subjects and we did not consider this correction aided our clinical interpretation of results.…”

“…If GH production occurs predominantly during the first few hours of sleep, an untimed overnight urine collection measuring total (sleeping) G H excretion will reflect this surge in GH production and timed estimations of GH excretion may not be required. Clinical factors which influence serum GH concentration include age (Zadik et al, 1985), particularly in females where pre and post-menopausal oestrogen status is important (Dawson-Hughes et al, 1986;Finkelstein et al, 1972;Ho et al, 1987), sex (Ho et al, 1987), obesity (Rudman et at., 1981) and possibly height, (Batrinos et al, 1989). If these factors play an important predictive role in between-subject variability of urinary growth hormone estimation, it may be possible to improve discrimination between a healthy control population and patients with active pituitary pathology such as acromegaly, by correcting for significant predictive variables.…”

Quantitative growth hormone secretion and final adult height

“…None of the patients met the adult criteria for GH therapy (GH response < 9 mU/l), but four of the eight had peak GH responses lower than in any of the 40 subjects studied here, indicative that they cannot automatically be regarded as normal (Thorner et al, 1995;Wacharasindhu et al, 1996). Batrinos et al (1989) documented a greater GH response to GHRH in a group of 20 tall (> 187 cm) members of the Greek Presidential Guard compared to 17 civilians of normal stature (range 171-177 cm), a result at variance with the findings presented here. Diet, body fat and physical fitness are known to influence GH secretion and may account for the difference documented (Hagberg et al, 1988;Weltman et al, 1994).…”

“…Batrinos et al . (1989) documented a greater GH response to GHRH in a group of 20 tall (> 187 cm) members of the Greek Presidential Guard compared to 17 civilians of normal stature (range 171–177 cm), a result at variance with the findings presented here.…”

Constitutionally Tall Stature with Morphological Abnormality of the Pituitary Gland

“…Recent reports have suggested that some children and adolescents with constitutionally tall stature (CTS) have a disorder of the hypothalamo-pituitary regulation of GH secretion that is seen in acromegaly [1][2][3][4][5]. Therefore, it is important to investigate whether these patients are preacromegalic.…”