Temporal difference of thyrotropin-releasing hormone in prevention of testicular regression in golden hamsters exposed to short photoperiods: possible involvement of beta-endorphin.
Male golden hamsters were exposed to long photoperiod or short photoperiod (SP) and injected with 1 microgram TRH and/or 1 microgram LHRH at lights on (LO) or lights off (LX) for a total of 8 weeks. Both TRH and LHRH prevented testicular regression if they were injected at LO. Injected at LX, TRH did not prevent testicular regression, and LHRH was only partially effective. Plasma beta-endorphin levels were significantly higher in groups with atrophic testes. These results indicate that TRH like LHRH can prevent SP-induced testicular regression in hamsters by some unknown mechanism and that beta-endorphin may be involved in the control of testicular function in hamsters.
Chen
H J
HJ
Targovnik
J
J
McMillan
L
L
Randall
S
S
D000818:Animals; D006224:Cricetinae; D004723:Endorphins / Q000502:physiology*; D005640:Follicle Stimulating Hormone / Q000097:blood; D005837:Genitalia, Male / Q000033:anatomy & histology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D008027:Light; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008647:Mesocricetus; D009929:Organ Size / Q000187:drug effects / Q000528:radiation effects; D010507:Periodicity; D011388:Prolactin / Q000097:blood; D013737:Testis / Q000033:anatomy & histology* / Q000187:drug effects / Q000528:radiation effects; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D001615:beta-Endorphin
D004723:Endorphins; D007987:Gonadotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone; D001615:beta-Endorphin; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone