TY - JOUR
T1 - Modification of testicular and thyroid function by chronic exposure to short photoperiod
T2 - A comparison in four rodent species
AU - Petterborg, L. J.
AU - Vaughan, M. K.
AU - Johnson, L. Y.
AU - Champney, T. H.
AU - Reiter, R. J.
N1 - Funding Information:
Photoperiod, the duration of light available during each 24 hr period, provides a reliable cue which can be utilized by an organism to elicit physiological adjustments necessary to its survival. The role of daylength in the regulation of reproductive function in rodents has received considerable attention (Reiter, 1978; Christian, 1980; Zucker et ul., 1980). The Syrian hamster (Mesocricetus aurcltus) has been extensively studied in this regard and provides a significant source of information with which the results of investigations on other species may be compared (Reiter, 1980; Stetson and Tate-Ostroff, 1981). While much is known concerning the reproductive consequences of photoperiodic manipulations, far less is known about how daylength may simultaneously affect other endocrine processes in rodents. Short photoperiod has been shown to cause a decrease in thyroid weight in female woodrats (Neotomcz micropus) maintained at 20°C (Capeheart and Burns, 1976). lower thyroxine (T,) levels in young male voles (Microfus montunus, Petterborg, 1978) and plasma levels of thyroid stimulating hormone (TSH), T,, and tri-iodothyronine (T,) in female hamsters (Vaughan et al., 1982). The thyroid inhibitory action of short photoperiod appears to be mediated by the *This work supported by NSF grant # PCM 8003441. i-Present address: Department of Anatomy, University of Missouri-Columbia, School of Medicine, Columbia, Missouri 65212. USA. $To whom correspondence should be addressed.
PY - 1984
Y1 - 1984
N2 - 1. 1. Exposure of male Syrian hamsters (Mesocricetus auratus) for 10 weeks to short photoperiod (SP) providing 10hr light:14hr 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). 2. 2. 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. 3. 3. Male gerbils (Meriones unguiculatus) exposed to 13 weeks of SP (10:14 LD) had lower body weights, testes and seminal vesicle weights and higher T,U 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 (FT3,I). 4. 4. 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. 5. 5. 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.
AB - 1. 1. Exposure of male Syrian hamsters (Mesocricetus auratus) for 10 weeks to short photoperiod (SP) providing 10hr light:14hr 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). 2. 2. 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. 3. 3. Male gerbils (Meriones unguiculatus) exposed to 13 weeks of SP (10:14 LD) had lower body weights, testes and seminal vesicle weights and higher T,U 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 (FT3,I). 4. 4. 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. 5. 5. 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.
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U2 - 10.1016/0300-9629(84)90087-2
DO - 10.1016/0300-9629(84)90087-2
M3 - Article
C2 - 6146435
AN - SCOPUS:0021267046
VL - 78
SP - 31
EP - 34
JO - Comparative Biochemistry and Physiology -- Part A: Physiology
JF - Comparative Biochemistry and Physiology -- Part A: Physiology
SN - 0300-9629
IS - 1
ER -