The Effect of Oxandrolone on the Growth Hormone Response to Growth Hormone Releasing Hormone in Children With Constitutional Growth Delay

Abstract

The effect of treatment with oxandrolone, an anabolic steroid, on GH response to GH-releasing hormone (GHRH) has been evaluated in children with constitutional growth delay. Five subjects, four males and one female, aged 11.0-17.1 years were given oxandrolone 0.1 mg/kg p.o. daily for 2 months, and underwent acute administration of GHRH (GRF 1-40, 1 microgram/kg i.v.) before and after withdrawal of oxandrolone therapy. GHRH administration induced a much greater GH response, evaluated either as a peak plasma GH levels or plasma GH integrated area, after than it did before oxandrolone treatment. These findings indicate that in children with constitutional growth delay oxandrolone increases the sensitivity of somatotrophs to exogenous GHRH and, likely, to the endogenously-released neurohormone.

Testosterone modulates growth hormone secretion at the hypothalamic but not at the hypophyseal level in the adult male rhesus monkey

“…Furthermore, chronic administration of tamoxifen, an oestrogen receptor blocker, to normal and testosterone-treated hypogonadal men (Weissberger & Ho 1993) leads to a significant reduction in mean serum GH concentrations, GH pulse amplitude and GH burst frequency. In contrast, studies in boys with constitutional delay in growth and development treated with non-aromatizable androgens suggested that testosterone affects GH secretion by acting directly on androgen receptors: an increase in basal (Clayton et al 1988) and GHRH-stimulated (Loche et al 1986) GH secretion has been reported in boys with constitutional delay in growth and development treated with oxandrolone. Similarly, Ulloa-Aguirre et al (1990) have demonstrated that treatment of boys with delayed growth and development with oxandrolone increases mean serum GH concentrations, GH pulse amplitude and mass of GH secreted per burst.…”

Final Height in Girls with Central Idiopathic Precocious Puberty Treated with Gonadotropin-Releasing Hormone Analog and Oxandrolone

“…Studies on the effect of the steroid on the somatotropic axis have provided conflicting results, with some showing a positive effect (14) and others showing no effect at all (15)(16)(17). Those showing an increase in GH secretion included few patients with highly variable responses (14,15). In agreement with previous studies (13,32), in the present study, GnRHa therapy alone or in combination with Ox had no effect on IGF-I concentrations, further supporting a somatotropic-independent mechanism of action of the steroid.…”

“…The precise mechanism of the growth acceleration induced by Ox is still unclear. Studies on the effect of the steroid on the somatotropic axis have provided conflicting results, with some showing a positive effect (14) and others showing no effect at all (15)(16)(17). Those showing an increase in GH secretion included few patients with highly variable responses (14,15).…”

“…The exact mechanism of its growth-promoting effect has not been completely elucidated. An activating effect of Ox on the somatotropic axis via distinct neuroendocrine secretory mechanisms was reported by some authors (14,15) but not confirmed by others (16,17). In addition, IGF-I concentrations were unaffected by Ox administration (11), further supporting a somatotropic-independent mechanism of action of the steroid.…”

A Boy with "transient" Growth Hormone Deficiency in Prepubertal Stage Despite Normal Growth Hormone Secretion in Childhood and after Puberty

“…Moreover, at this time, the gonadotropins response to LHRH and serum testosterone levels were slightly elevated. In certain studies, it is recommended that GH secretion should be re-evaluated in puberty or on priming with sex steroids [15][16][17][18] in subjects with isolated GHD without any morphological abnormality in the pituitary gland. We did not perform priming with sex steroids because of the clinical course and certain limitations of this procedure (it is not physiologic or standardized, and the cut-off limits are not available) [12].…”