Abstract
To determine whether changes in gonadotropin-releasing hormone (GnRH) neurons are early indicators of photostimulation, Siberian hamsters were placed in short days (6:18-h light-dark) at 3 (experiment 1) or 6 (experiment 2) wk of age where they were held for 3 (experiment 1) or 4 (experiment 2) wk. Hamsters were then moved to long photoperiod (16:8-h light-dark). In experiment 1, brains were collected 1-21 days after transfer from short to long days. In experiment 2, brains were collected only on the second morning of long day exposure. Long and short day controls were included in both experiments. Cells containing GnRH mRNA, as visualized by in situ hybridization, were counted. As expected, there were no differences in the number of detectable GnRH mRNA-containing cells among animals chronically exposed to long or short photoperiods. However, on the second morning after transfer from short to long photoperiod, a positive shift in the distribution of GnRH mRNA-containing cells occurred relative to the respective controls in the two experiments. Increases in follicle-stimulating hormone secretion and gonadal growth occurred days later. In conclusion, a rapid but transient increase in the distribution of detectable GnRH mRNA-cont...Continue Reading
References
Sep 1, 1977·The Journal of Endocrinology·B K FollettB Gledhill
Dec 1, 1979·The Journal of Endocrinology·G E Pickard, A J Silverman
Sep 1, 1978·Journal of Reproduction and Fertility·K Hoffmann
Feb 1, 1992·Neuroendocrinology·E RonchiD W Pfaff
Feb 1, 1992·Neuroendocrinology·E RonchiD W Pfaff
Aug 1, 1991·Neuroendocrinology·K L Buchanan, S M Yellon
Sep 1, 1991·Biology of Reproduction·S M Yellon, S W Newman
Oct 1, 1991·Endocrinology·J M MeredithJ E Levine
Apr 1, 1991·Biology of Reproduction·H F UrbanskiM Pierce
Nov 1, 1990·Endocrinology·H F Urbanski
Jan 1, 1986·Proceedings of the National Academy of Sciences of the United States of America·J P AdelmanP H Seeburg
Jan 1, 1985·Neuroscience and Biobehavioral Reviews·R W StegerA Bartke
May 1, 1987·Journal of Reproduction and Fertility·S M Yellon, B D Goldman
Jul 1, 1985·Endocrinology·A C RobertsJ Herbert
May 1, 1986·Endocrinology·R J ReiterF Nürnberger
Apr 1, 1982·Biology of Reproduction·R W StegerB D Goldman
Mar 1, 1984·The Journal of Experimental Zoology·R W StegerF Talamantes
Feb 1, 1984·Endocrinology·S M Yellon, B D Goldman
Oct 1, 1984·Biology of Reproduction·F L JacksonA S Berkowitz
Jul 1, 1982·Endocrinology·F W Turek
Sep 1, 1982·Journal of Reproduction and Fertility·S M SimpsonD H Ellis
Jul 1, 1995·Journal of Neuroendocrinology·F J EblingM H Hastings
Sep 1, 1995·Biology of Reproduction·A M WolfeJ E Levine
Feb 1, 1994·Biology of Reproduction·S M Yellon
Sep 1, 1993·Biology of Reproduction·C S WhalingI Zucker
Jun 7, 1996·Neuroscience Letters·M R Gorman, S M Yellon
Apr 1, 1996·Biology of Reproduction·K M Stanfield, T H Horton