Modification of testicular and thyroid function by chronic exposure to short photoperiod: a comparison in four rodent species.
Exposure of male Syrian hamsters (Mesocricetus auratus) for 10 weeks to short photoperiod (SP) providing 10 hr light: 14 hr darkness (10:14 LD) produced a significant reduction in the weights of the reproductive organs, plasma thyroxine (T4) levels and free T4 index (FT4I) compared to the values of animals exposed to long photoperiod (LP, 14:10 LD). C57bl male house mice (Mus musculus) kept in SP (10:14 LD) had reproductive organ weights equivalent to those of mice kept in long days (14:10 LD) and lower T3 uptake (T3U) values. Male gerbils (Meriones unguiculatus) exposed to 13 weeks of SP (10:14 LD) had lower body weights, testes and seminal vesicle weights and higher T3U values compared to LP (14:10 LD) controls. However, no effect was seen on plasma T4 and triiodothyronine (T3) values nor the FT4I and free T3 index (FT3I). White-footed male mice (Peromyscus leucopus) exposed to SP (8:16 LD) had significantly lower testes and seminal vesicle weights while plasma T4 and T3 levels were unaffected. Snell strain house mice (Mus musculus) exposed to SP (8:16 LD) had normal reproductive organ weights compared to the values of LP-exposed (16:8 LD) control animals. However, there was a significant depression in T3 and in the FT3I in the SP animals.
D000818:Animals; D006224:Cricetinae; D005837:Genitalia, Male / Q000033:anatomy & histology; D005849:Gerbillinae; D008027:Light; D008297:Male; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009929:Organ Size; D010507:Periodicity; D010542:Peromyscus; D013737:Testis / Q000502:physiology*; D013961:Thyroid Gland / Q000502:physiology*; D013963:Thyroid Hormones / Q000097:blood
D013963:Thyroid Hormones