Reduced levels of GH during GnRH analogue treatment in pubertal short girls born small for gestational age (SGA)

Efficacy and safety of a 4-year combination therapy of growth hormone and gonadotropin-releasing hormone analogue in pubertal girls with short predicted adult height

OBJECTIVES

To improve adult height in pubertal girls with a poor height prediction, treatment with growth hormone (GH) can be used in combination with a gonadotropin releasing hormone agonist (GnRHa), to delay closure of the growth plates. However, there are few studies to support this practice, and they show conflicting results. The objective of this trial is to assess the safety and efficacy of this combination treatment in early pubertal girls with a short predicted height, in comparison with matched controls.

DESIGN PATIENTS AND METHODS

We designed an open-label, multicenter, interventional case-control study. Early pubertal girls with predicted adult height (PAH) below -2.5 SDS, were recruited in tertiary care centers in Belgium. They were treated for four years with GH and GnRHa. The girls were followed until adult height (AH) was reached. AH vs PAH, AH vs Height at start, and AH vs Target Height (TH) were evaluated, as well as safety parameters. Control data were assembled from historical patient files or from patients who preferred not to participate in the study.

RESULTS

Sixteen girls with mean age ( ± SD) at start of 11.0 years (± 1.3) completed the study protocol and follow-up. Their mean height ( ± SD) increased from 131.3 ± 4.1 cm (-2.3 ± 0.7 SDS) at start of treatment to 159.8 ± 4.7 cm (-1.1 ± 0.7 SDS) at AH. In matched controls, height increased from 132.3 ± 4.2 cm (-2.4 ± 0.5 SDS) to 153.2 ± 3.4 cm (-2.1 ± 0.6 SDS) (p<0.001). AH surpassed initial PAH by 12.0 ± 2.6 cm in treated girls; and by 4.2 ± 3.6 cm in the controls (p<0.001). Most treated girls reached normal adult height (>-2SD) (87.5%) and 68.7% reached or superseded the target height (TH), which was the case in only a minority of the controls (37.5% and 6.2%, respectively) (p= 0.003 and 0.001). A serious adverse event possibly related to the treatment, was a fracture of the metatarsals.

CONCLUSION

A four-year GH/GnRHa treatment in early pubertal girls with a poor PAH seems safe and results in a clinically relevant and statistically significant increase in AH compared with matched historical controls.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT00840944.

Intracerebroventricular injection of RFRP-3 delays puberty onset and stimulates growth hormone secretion in female rats

BACKGROUND

Puberty onset is a complex, organized biological process with multilevel regulation, and its physiopathological mechanisms are yet to be elucidated. RFRP-3, the mammalian ortholog to gonadotropin-inhibitory hormone, is implicated in inhibiting the synthesis and release of gonadotropin in mammals. However, it is unclear whether RFRP-3 participates in regulating pubertal development.

METHODS

This study investigated the functional significance and regulatory mechanism of hypothalamic RFRP-3 neuropeptide in the onset of puberty in young female rats. On postnatal day 22, we implanted cannulas into the lateral ventricles of female rat pups. From postnatal day 28 to postnatal day 36, the intracerebroventricular injection of RFRP-3, or vehicle, was conducted twice a day. To investigate whether puberty onset was affected, we examined the body weight, age of vaginal opening, serum hormone levels, uterus and ovary development, and hypothalamic Kiss-1 mRNA expression.

RESULTS

Intracerebroventricular injection of RFRP-3 significantly decreased the serum concentrations of luteinizing hormone and estradiol, delayed uterine maturation, and postponed the time of vaginal opening. This study suggests that RFRP-3 can delay the onset of puberty in young female rats; the expression of Kiss-1 mRNA is potently inhibited in the RFRP-3 group. Moreover, our data show that RFRP-3 elevates serum growth hormone levels.

CONCLUSIONS

These data suggest that intracerebroventricular injection of RFRP-3 significantly delays the onset of puberty in female rats. Additionally, RFRP-3 may be associated with prepubertal rise in the secretion of growth hormone.

Randomized GH trial with two different dosages in combination with a GnRH analogue in short small for gestational age children: effects on metabolic profile and serum GH, IGF1, and IGFBP3 levels

BACKGROUND

GnRH analogue (GnRHa) combined with GH treatment has been proposed to increase adult height. Effect on metabolic profile and GH, IGF1, and IGFBP3 levels in short small for gestational age (SGA) children is unknown.

OBJECTIVE

To assess fat mass and lean body mass SDS, percentage trunk fat, blood pressure (BP), insulin sensitivity (Si), beta-cell function (disposition index, DI), lipid profile, and GH, IGF1, and IGFBP3 levels during 2 years of combined treatment.

SUBJECTS

Forty-one pubertal short SGA children with a mean (+/-S.D.) age of 12.1 (+/-1.0) years.

DESIGN

Children received 3.75 mg of leuprolide acetate depot subcutaneously every 4 weeks, and they were randomly assigned to receive 1 mg (group A) or 2 mg (group B) of GH/m(2) per day.

RESULTS

Percentage trunk fat increased in both groups, but to a lower extent in group B. Lean body mass SDS increased only in group B. Changes in BP, Si, DI, and lipids were similar in both groups. Si significantly decreased, but DI remained unchanged. Lipids remained normal. GH and IGF1 levels were significantly higher in group B.

CONCLUSION

Our study is the first to report that 2 years of combined treatment with a GnRHa and either 1 or 2 mg GH/m(2) per day does not adversely affect body composition and metabolic profile of short SGA children who come under medical attention at the onset of puberty. There was a dose-dependent effect on fat mass SDS(height), percentage trunk fat, lean body mass SDS(height), and GH and IGF1 levels in favor of treatment with GnRHa and the higher GH dose of 2 mg/m(2) per day.