Hormonal regulation of epidermal growth factor and insulin-like growth factor-I in adult male hypophysectomized rats treated with ethane dimethane sulphonate.
There is increasing evidence implicating growth factors in the regulation of spermatogenesis and in-vitro studies have shown that epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) interact with the gonadotrophins in regulating testicular function. In the present study, the effect of FSH, testosterone and GH treatment on serum IGF-I and intratesticular EGF and IGF-I concentrations in adult male hypophysectomized rats treated with ethane dimethane sulphonate (EDS) to destroy Leydig cells has been investigated. Hypophysectomy alone or followed by EDS treatment was associated with a significant increase in intratesticular EGF concentrations compared with normal controls (P less than 0.05). Treatment of hypophysectomized animals with a combination of GH, FSH and testosterone resulted in a return of intratesticular EGF concentrations to normal control levels. In a second group of animals treated with a 5 cm silicone elastomer implant of testosterone and FSH, intratesticular EGF concentrations were also not significantly different from those of normal controls. Following hypophysectomy alone or hypophysectomy and EDS treatment, a significant increase in circulating IGF-I concentrations occurred, which was only reversed following the administration of GH. In addition, increases in testicular IGF-I concentrations were evident in all treated animals compared with controls, an effect which was only partially reversed in animals treated with a combination of FSH and testosterone (1.5 or 5 cm implant). Similar results were obtained with a combination of GH and FSH or GH and testosterone, although GH alone had no effect on testicular IGF-I concentrations. A combination of GH, FSH and testosterone restored testicular IGF-I to concentrations not significantly different from controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Spiteri-Grech
J
J
Max Planck Clinical Research Unit for Reproductive Medicine, The University, Münster, Federal Republic of Germany.
Bartlett
J M
JM
Nieschlag
E
E
D000818:Animals; D004815:Epidermal Growth Factor / Q000378:metabolism; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D013006:Growth Hormone / Q000494:pharmacology; D006133:Growth Substances / Q000378:metabolism*; D007016:Hypophysectomy; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008698:Mesylates / Q000494:pharmacology*; D010908:Pituitary Hormones, Anterior / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000187:drug effects / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*
D006133:Growth Substances; D008698:Mesylates; D010908:Pituitary Hormones, Anterior; D013739:Testosterone; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone; C002994:ethylene dimethanesulfonate