Gonadal steroid regulation of hamster facial nerve regeneration

Effects of dihydrotestosterone and estradiol

Lisa Tanzer, Kathryn Jones

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

We have demonstrated, in a series of experiments, the therapeutic potential of androgens in facial motoneuron regeneration in the adult hamster. Initial work utilized testosterene propionate (TP) as the form of androgen given to adult hamster at the time of facial nerve crush axotomy at its exit from the stylomastoid foramen. TP is capable of being enzymatically converted to estrogen. Thus, the effects of TP on the regenerative properties of facial motoneurons could be due to androgens, estrogens, or both. Recent studies of androgen receptor (AR) mRNA levels suggest that androgens and estrogens work synergistically to regulate AR expression in these motoneurens. In this study, we examined the ability of dihydrotestosterone propionate (DHTP), a nonaromatizable androgen which cannot be converted to estrogen, and estradiol (E2) to alter facial nerve regeneration, using fast axonal transport of radioactively labeled proteins to assess facial nerve regeneration. Adult gonadectomized male hamsters were subjected to right facial nerve crush axotomy, with the left side serving as control, and divided into three groups. One-third of the animals received 1 subcutaneous implant of DHTP, one-third received 1 subcutaneous implant of E2, and the remaining third was sham implanted. Postoperative survival times were 4 and 7 days. As expected, DHTP treatment resulted in an approximately 40% increase in the rate of regeneration, with an associated prolongation in the delay time before sprouting occured. These effects were slightly greater than previously observed with TP, as might be predicted given the more potent physiological effects observed with DHTP compared to TP. Surprisingly, E2 treatment also resulted in an increase in the rate of regeneration (30%), with minimal effects on the delay time before sprout formation occured. The results argue for a synergistic role for androgens and estrogens in augmenting peripheral nerve regeneration in the model system used in this study.

Original languageEnglish (US)
Pages (from-to)258-264
Number of pages7
JournalExperimental Neurology
Volume146
Issue number1
DOIs
StatePublished - Jul 1997
Externally publishedYes

Fingerprint

Nerve Regeneration
Dihydrotestosterone
Facial Nerve
Cricetinae
Propionates
Androgens
Estradiol
Steroids
Estrogens
Nerve Crush
Axotomy
Regeneration
Androgen Receptors
Motor Neurons
Axonal Transport
Peripheral Nerves
Messenger RNA
dihydrotestosterone propionate
Proteins

ASJC Scopus subject areas

  • Neurology
  • Neuroscience(all)

Cite this

Gonadal steroid regulation of hamster facial nerve regeneration : Effects of dihydrotestosterone and estradiol. / Tanzer, Lisa; Jones, Kathryn.

In: Experimental Neurology, Vol. 146, No. 1, 07.1997, p. 258-264.

Research output: Contribution to journalArticle

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