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Fig. 9 | Reproductive Biology and Endocrinology

Fig. 9

From: Increased testicular insulin-like growth factor 1 is associated with gonadal activation by recombinant growth hormone in immature rats

Fig. 9

Local increase in IGF1 levels in the testes might be an important mediator for gonadal activation triggered by rhGH in immature rats. Changes in kisspeptin, GnRH, LH, IGF1, and testosterone in the hypothalamus-pituitary-testis axis following daily injections of rhGH from PND 21 to 23 or PND 21 to 30 are summarized. Testicular steroidogenesis, circulating testosterone, and spermatogenesis were higher than control levels in the rhGH rats on PNDs 24 and 31. Hypothalamic Kiss1, Gnrh1, and Igf1 mRNA levels were also higher than control levels in rhGH rats on PND 24, but they became lower than the control levels by PND 31. No significant change in circulating LH levels was observed on PND 24 or 31 in the rhGH rats. In prepubertal male rats, rhGH administration increased testicular but not systemic IGF1 levels, which potentiated testosterone production in LCs and thus increased circulating testosterone, stimulating sexual maturation and spermatogenesis

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Reproductive Biology and Endocrinology

ISSN: 1477-7827

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