Effects of FSH and testosterone on intratesticular insulin-like growth factor-I and specific germ cell populations in rats treated with gonadotrophin-releasing hormone antagonist.
Evidence derived predominantly from a series of in-vitro studies indicates that insulin-like growth factor-I (IGF-I) plays an important role as a paracrine and autocrine regulator within the testis. We investigated the effects of FSH substitution on spermatogenesis and testicular IGF-I content in rats treated with gonadotrophin-releasing hormone (GnRH) antagonist (ANT) and injected with ethane dimethane sulphonate (EDS), a Leydig cell toxin. FSH treatment partially prevented the marked decrease in intratesticular IGF-I in rats treated with only GnRH antagonist but not in GnRH antagonist+EDS-treated animals (controls, 191.0 +/- 4.5; ANT, 80.1 +/- 5.6; ANT+EDS, 81.6 +/- 3.4; ANT+EDS+FSH, 86.3 +/- 1.4; ANT+FSH, 137.7 + 7.3 (S.E.M.) ng/testis). Correlation analysis of testicular IGF-I content with the number of pachytene spermatocytes and round spermatids per cross-section revealed r values of 0.77 and 0.74 respectively (P < 0.001). We then analysed the same parameters in GnRH antagonist-treated rats which, in addition, received daily injections of the anti-androgen flutamide, in order to investigate the potential role of testosterone, as opposed to other Leydig cell products, in the regulation of spermatogenesis and testicular IGF-I. FSH treatment prevented regression of spermatogenesis in rats treated with GnRH antagonist alone but not in GnRH antagonist- and flutamide-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Institute of Reproductive Medicine, University of Münster, Germany.
J
J
Spiteri-Grech
G F
GF
Weinbauer
P
P
Bolze
R K
RK
Chandolia
J M
JM
Bartlett
E
E
Nieschlag
D000818:Animals; D005485:Flutamide / Q000494:pharmacology; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008698:Mesylates / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012671:Seminiferous Tubules / Q000033:anatomy & histology; D013076:Sperm Count; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000166:cytology*; D013737:Testis / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*
D008698:Mesylates; C043699:detirelix; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D005485:Flutamide; D005640:Follicle Stimulating Hormone; C002994:ethylene dimethanesulfonate