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15:44 - 15:47
S2-4
(PP)
COMBINATION OF GROWTH HORMONE WITH TESTOSTERONE IS HELPFUL TO
NORMALIZE PENILE SIZE IN HYPOGONADAL RATS WITH MICROPENIS
Kwanjin PARK
1
, Jung Keun LEE
1
and Dong IL KANG
2
1) Seoul National University Children's Hospital, Department of Urology, Seoul, KOREA (REPUBLIC OF) - 2) Inje
University, College of Medicine, Department of Urology, Busan, KOREA (REPUBLIC OF)
PURPOSE
Testosterone treatment of micropenis is often refuted by the concern that it may result in premature termination of
penile growth caused by downregulation of penile androgen receptors (ARs). This study was designed to test the
assumption that combination treatment with growth hormone (GH) is preferable to conventional testosterone treatment
by suppressing downregulation of ARs.
MATERIAL AND METHODS
Fifty Sprague-Dawley rats were equally grouped into control (C), micropenis (MP), testosterone monotherapy (T),
growth hormone monotherapy (G) and growth hormone plus testosterone (GT). Apart from C, micropenis secondary to
hypogonadotropic hypogonadism was induced in the remained 40 using leuprolide acetate. Prepubertal administration of
testosterone or GH began 7 days after birth and continued up to 12 weeks of age. Comparison of penile length, weight,
mean testicular weight and volumetric comparison of collagen
Ⅰ
,
Ⅲ
and smooth muscle was used to evaluate the effect
of each treatment. The expression of androgen receptor was evaluated to understand potential mechanism of action.
RESULTS
Although mean penile length or weight of T was larger than G or MP, it was shorter than C. Conversely, GT was
comparable to C in mean penile length as well as weight. All investigated components, especially smooth muscle actin,
were increased in GT. Higher androgen receptor expression than C was only seen in combination arm.
CONCLUSIONS
Growth hormone can supplement androgen action and help to increase penile size. It maintained higher androgen
receptor expression which could explain the result.