Neurotrophic-hormonal interaction in the regulation of taste buds in the rat's vallate papilla.

Abstract

AbstractProlonged treatment of castrated‐male rats with testosterone causes the development of taste buds in abnormal locations in the vallate papilla (i.e., upper surface of the papilla). Since taste buds are morphologically dependent on a trophic factor delivered to them via intact gustatory nerves, investigations of the possible role of testosterone as a trophic agent were undertaken. The effects of testosterone propionate on taste buds were studied in normal male and female, castrated‐male, and male rats in which the taste buds were totally denervated. There was no apparent change in the number, distribution, or appearance of the taste buds normally found in the trench walls of testosterone treated normal or castrated rats. However, in the normal‐male and castrated‐male rats, 1–3 taste buds were found on the top surface of the papilla 6 weeks after treatment. No new buds were seen at 1 or 2 weeks, nor were any seen in hormonally treated females, or in control animals injected with sesame oil alone. Furthermore, testosterone did not maintain old or initiate new taste bud formation in the denervated papilla. Thus, testosterone in the form, doses, and times employed, could not subserve the trophic function of intact gustatory nerves. The results however indicate that new taste bud formation is the result of a nerve–hormone interaction, and not a change induced by castration and subsequent testosterone treatment. Further studies of the nerve–hormone interaction involved in taste bud formation seem indicated.