Institut für Molekulare Endokrinologie und Physiologie

Prof. Dr. Annika Herwig

Research interests

The main focus of our research is to understand the mechanisms controlling seasonal adaptations in small mammals. Mammals living in seasonal environments face regular and predictable energetic bottlenecks at a particular time of year. In temperate zones, winter is the critical time when food sources are limited and at the same time ambient temperature is low. Many seasonal mammals show extreme morphological and physiological adaptations to overcome this energetic challenge. 
We mainly work on Djungarian hamsters that precisely adjust reproduction, body mass and metabolism to the time of year. These animals show a particularly remarkable annual body weight cycle that is precisely controlled by photoperiod and moreover, use daily torpor. During torpor, metabolic rate is downregulated by 80 % and body temperature drops to values between 15-25°C – a striking state for an endothermic mammal!
Combining in vivo, histological, biochemical and molecular methods, we aim to identify how the brain controls these profound adjustments of energy balance and metabolism. The underlying regulatory mechanisms are of great interest, since they are able to control body weight and metabolism very precisely in the long-term and over an extreme range. Understanding them is of great interest for basic physiology as well as for translational approaches.  
 
 

 

Djungarian hamster (Phodopus sungorus)
Djungarian hamster
Portrait Annika Herwig

Dr. Victoria Diedrich

Research

Since my Bachelor studies at the Philipps University of Marburg, I have been fascinated by Djungarian hamsters and their remarkable ability to survive the extreme winter conditions of the Siberian steppes. Especially the research on daily torpor as an important part of the hamsters' complex winter acclimatization runs through my entire scientific work at the University of Veterinary Medicine in Hannover and now at Ulm University.

In the research group of Prof. Herwig, I investigate the influence of the hamsters' energetic state with special respect to glucose availability on torpor expression as a potential proximate trigger, as we still do not know which stimulus or interplay of stimuli tells a hamster on a certain day to show a torpor bout. Therefore, I do not only focus on spontaneous daily torpor in winter acclimated hamsters, but also compare it to fasting-induced torpor in summer acclimated hamsters, as these two forms of torpor are just two sides of the same medal.

For my research, I use the following experimental paradigms and methods:

in vivo:

  • radio frequency based telemetry to continously measure body core temperature
  • respiratory gas analysis to measure metabolic rate via indirect calorimetry
  • continuous telemetry to measure blood glucose content
  • food restriction paradigms

in vitro:

  • histochemical and molecluar examination of the intestinal tract
  • immunohistochemical examination of brain tissue

  

Publications

2022
Haugg E, Borner J, Diedrich V, Herwig A (2022) Comparative transcriptomics of the Djungarian hamster hypothalamus during short photoperiod
acclimation and spontaneous torpor. FEBS Open Bio 12(2): 443-459, doi: 10.1002/2211-5463.13350.

2021
Haugg E, Herwig A, Diedrich V (2021) Body temperature and activity adaptation of short photoperiod-exposed Djungarian hamsters (Phodopus sungorus): Timing, traits, and torpor. Front Physiol 12, doi: 10.3389/fphys.2021.626779.

Piscitiello E, Herwig A, Haugg E, Schröder B, Breves G, Steinlechner S, Diedrich V (2021) Acclimation of intestinal morphology and function in Djungarian hamsters (Phodopus sungorus) related to seasonal and acute energy balance. J Exp Biol 224(4), doi: 10.1242/jeb.232876.

2020
Wardenga N, Diedrich V, Waldmann B, Lenarz T, Maier H (2020) Hearing aid treatment in patients with mixed hearing loss. Part I: expected benefit and limitations after stapes surgery. Audiol Neurotol 25(3): 125-132, doi: 10.1159/000502994.

Diedrich V, Haugg E, Dreier C, Herwig A (2020) What can seasonal models teach us about energy balance? J Endocrinol 244(2): R17-R32.  DOI: 10. 1530/JOE-19-0502.

2019
Yu H, Dilbaz S, Coßmann J, Hoang AC, Diedrich V, Herwig A, Harauma  A, Hoshi Y, Moriguchi T, Landgraf K, Körner A, Lucas C, Brodesser S, Balogh L, Thuróczy J, Karemore G, Kuefner MS, Park EA, Rapp C, Travers JB and Röszer T (2019) Breast milk alkylglyerols sustain beige adipocytes through adipose tissue macrophages. J Clin Invest 129(6); DOI 1172/JCI125646.

2018
Voigt H, Diedrich V, Lenarz T, Haverich H (2018) Survery of the translation situation in the Lower Saxony Center for Biomedical Engineering Implant Research and Development (NIFE) and involved clinics. Laryngo Rhino Otol 97 (S02): 10576, doi: 10.1055/s-0038-1639895.

2017
Dumbell RA, Petri I, Scherbath F, Diedrich V, Schmid HA, Steinlechner S, Barrett P (2017) Stomatostatin agonist pasireotide inhibits exercise-stimulated growth in male Siberian hamster (Phodopus sungorus). J Neuroendocrinol, 11/2017,29(1); Doi: 10.1111/jne.12448. 

Petri I, Diedrich V, Wilson D, Calleja-Fernández J, Herwig A, Steinlechner S, Barrett P (2016) Orchestration of gene expression across the seasons: Hypothalamic gene expression in natural photoperiod troughout the year in the Siberian hamster. Scientific Reports, 07/2016, 6(29689); DOI: 10.1038/srep29689. 

2015
Diedrich V (2015) Daily torpor in Djungarian Hamsters (Phodopus sungorus): energetics and environmental challenges. Inaugural-Dissertation, University of Veterinary Medicine, Hannover, pp. 94.

Diedrich V, Bank JH, Scherbarth F, Steinlechner S (2015) Torpor expression in juvenile and adult Djungarian hamsters (Phodopus sungorus) differs in frequncy, duration and onset in reponse to a daily cylce in ambient temperature. Journal of Thermal Biology, 08/2015, 53; DOI: 10.1016/jtherbio.2015.08.006. 

Scherbarth F, Diedrich V, Dumbell RA, Schmid HA, Steinlechner S, Barrett P (2015) Somatostatin receptor activation is involved in the control of daily torpor in a seasonal mammal. American Journal of Physiology - Endocrinology and Metabolism, 07/2015, 309(6); DOI: 10.1152/ajpregu.00191.2015. 

Dumbell RA, Scherbarth F, Diedrich V, Schmid H, Steinlechner S, Barrett P (2015) Somatostatin agonists promote a physiological state resembling short-day acclimatization in the photoperiodic male Siberian hamster (Phodopus sungorus). Journal of Neuroendocrinology, 05/2015, 27(7); DOI: 10.1111/jne.12289. .

2014
Diedrich, V, Kumstel S, Steinlechner S (2014) Spontaneous daily torpor and fasting-induced torpor in Djungarian hamsters are characterized by distinct patterns of metabolic rate. Journal of Comparative Physiology B, 12/2014, 185(3); DOI: 10.1007/s00360-014-0882-4. 

Diedrich V, Steinlechner S, Scherbarth F (2014) Effects of unsaturated fatty acids on torpor frequency and diet selection in Djungarian hamsters (Phodopus sungorus). Journal of Experimental Biology, 10/2014, 217(24); DOI: 10.1242/jeb.113217.

Diedrich V, Scherbarth F, Jähnig S, Kastens S, Steinlechner S (2014) Djungarian hamsters (Phodopus sungorus) are not susceptible to stimulating effects of 6-methoxy-2-benzoxazolinone on reproductive organs. Science of Nature, 01/2014, 101(2); DOI: 10.1007/s00114-013-1138-y.

2012
Diedrich V, Steinlechner S (2012) Spontaneous daily torpor versus fasting-induced torpor in the Djungarian hamster (Phodopus sungorus): two sides of a medal or distinct phenomena? In: Ruf T, Bieber C, Arnold W, Millesi E (eds). Living in a seasonal world: thermoregulatory and metabolic adaptations. Springer, Berlin, Heidelberg, pp 231-242. 

Conference contributions

2021
Diedrich V, Haugg E, Herwig A (2021) In vivo blood glucose measurements during daily torpor in Djungarian hamsters (Phodopus sungorus). 16th International Hibernation Symposium, Groningen, 01.08.-05.08.2021, oral presentation.

Höfer DG, Dreier C, Diedrich V, Herwig A (2021) Differential expression of GLUT1,3,4 in the hypothalamus of torpid and non-torpid  Djugarian hamsters (Phodopus sungorus). 16th International Hibernation Symposium, Groningen, 01.08.-05.08.2021, oral presentation.

2019
Piscitiello E, Herwig A, Schröder B, Breves G, Steinlechner S, Diedrich V (2019) Acclimation of intestinal morphology and function in Djungarian hamsters (Phodopus sungorus) related to seasonal and accute energy balance. 112. Jahrestagung der Deutschen Zoologischen Gesellschaft, Jena, 10.09. - 13.09.2019, 41, oral presentation.

Haugg E, Diedrich V, Herwig A (2019) Neuroanatomical mapping of hypythalamic core areas involved in the regulation of spontaneous daily torpor in the Djungarian hamster (Phodopus sungorus). 13th Göttingen Meeting of the German Neuroscience Society, Göttingen, 20.03.-23.03.2019, poster.

Haugg E, Diedrich V, Herwig A (2019) Continuous telemetric monitoring of body core temperature to assess hypothermia resulting from metabolic depression during spontaneous daily torpor in Djungarian hamsters ( Phodopus sungorus). DSI European User Group Meeting, Berlin, 28.03. - 29.03.2019, Berlin, poster.

2018
Haugg E, Diedrich V, Herwig A (2018) Nail down torpor-related genes in the brain. 11th Student Symposium on Molecular Medicine, Ulm, 05.05.2018, poster.

2014
Diedrich V, Steinlechner S (2014) Influence of an environmental stressor on torpor expression in Djungarian hamsters (Phodopus sungorus). Satelliten-Symposium "Epigenetics in animal physiology" im Rahmen der 107. Jahrestagung der Deutschen Zoologischen Gesellschaft, Göttingen, 10.9.-11.9.2014. oral presentation.

Diedrich V, Steinlechner S, Scherbarth F (2014) Dietary composition of unsaturated fatty acids is of minor importance for the occrrence of daily torpor in the seasonal dwarf hamster Phodopus sungorus. 107. Jahrestagung der Deutschen Zoologischen Gesellschaft, Göttingen, 11.9.-11.9.2014, 119.  oral presentation. 

2013
Bank J, Diedrich V, Steinlechner S (2013) Daily ambient temperatur cycles influence the expression of spontaneous daily torpor in juvenile Djungarian hamsters (Phodopus sungorus). 106. Jahrestagung der Deutschen Zoologischen Gesellschaft, München, 13.9.-16.9.2013, 398, poster. 

Diedrich V, Steinlechner S (2013) Spontaneous daily torpor versus fasting-induced torpor: Further repirometric characterizatioin in Djungarian hamsters (Phodopus sungorus). 106. Jahrestagung der Deutschen Zoologischen Gesellschaft, München, 13.9.-16.9.2013, 401, poster.

2012
Diedrich V, Scherbarth F, Jähnig S, Kastens S, Steinlechner S (2012) Spring fever in Djungarian hamsters is not triggered by the uptake of 6-Methoxy-2-benzoxazolinone. 105. Jahrestagung der Deutschen Zoologischen Gesellschaft, Konstanz, 21.9.-24.9.2012, 199-200, poster.

Morisset R, Scherbarth F, Diedrich V, Steinlechner S (2012) Even a locked running wheel affects short-day acclimation in Djungarian hamsters. 105. Jahrestagung der Deutschen Zoologischen Gesellschaft, Konstanz, 21.9.-24.9.2012, 206-207, poster.

Diedrich V, Steinlechner S (2012) Spontaneous daily torpor versus fasting-induced torpor in the Djungarian hamster (Phodopus sungorus). 14th International Hibernation Symposium, Semmering, 8.8.-14.08.2012, oral presentation.

Djungarian hamster during the seasonal moult from the white, well-insulating winter fur to the gray-brown summer fur. In contrast to the moult from summer to winter transition, this fur change from winter to summer is very unstructured and leaves the hamsters look like motley cows
Djungarian hamster during the seasonal moult from the white, well-insulating winter fur to the gray-brown summer fur

Contact

  • Dr. Victoria Diedrich
  • Room: M25/5212
  • Phone: +49 (0) 731-50- 22685
  • Fax: +49 (0) 731-50-22629