Impact of neonatal hypothyroidism on reproduction in the male hamster, Mesocricetus auratus

Heiko T. Jansen, John D. Kirby, Paul S. Cooke, Niromi Arambepola, Gary A. Iwamoto

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Thyroid hormones play an important role in brain development. In the present study, we examined the influence of transient postnatal hypothyroidism on reproductive neuroendocrine and behavioral outcomes in the male Syrian (golden) hamster. Hamster pups were rendered hypothyroid following exposure to the goitrogen, 6-n-propyl-2-thiouracil (PTU), between postnatal (PN) day 0 (birth) and PN25 (weaning). By 15 days after cessation of PTU, exposure (PN40) serum thyroxine levels had returned to control levels. The testes of treated males were approximately 30% heavier than controls and daily sperm production was increased by 73%. Immunocytochemistry for GnRH revealed that the total number of GnRH neurons did not vary between groups; however, a shift in the distribution of GnRH neurons was observed in treated males such that more GnRH immunoreactive neurons were found in the caudal portion of their normal distribution. The shift in GnRH distribution was associated with a significant reduction (40-50%) in pituitary gonadotropin secretion. Behaviorally, treated males took significantly longer to investigate the anogenital region and then mount a receptive female. A corresponding reduction in the total number of anogenital investigations and mounts was observed. This difference between treated males and controls was reduced, but not eliminated, over successive trials and by the third trial the number of intromission was similar between treated and control males. We conclude that the full complement of adult reproductive functions observed in the male golden hamster requires thyroid hormones during the early postnatal period. The severity of the effects induced by early hypothyroidism in this species varies from transient to permanent, depending on the endpoint.

Original languageEnglish (US)
Pages (from-to)771-781
Number of pages11
JournalPhysiology and Behavior
Volume90
Issue number5
DOIs
StatePublished - Apr 23 2007

Fingerprint

Mesocricetus
Hypothyroidism
Cricetinae
Reproduction
Gonadotropin-Releasing Hormone
Propylthiouracil
Thyroid Hormones
Neurons
Pituitary Gonadotropins
Antithyroid Agents
Normal Distribution
Weaning
Thyroxine
Spermatozoa
Testis
Immunohistochemistry
Parturition
Brain
Serum

Keywords

  • GnRH
  • Gonadotropins
  • Hamster
  • Sex behavior
  • Spermatozoa
  • Testis
  • Thyroid
  • Thyroxine

ASJC Scopus subject areas

  • Behavioral Neuroscience
  • Physiology (medical)

Cite this

Impact of neonatal hypothyroidism on reproduction in the male hamster, Mesocricetus auratus. / Jansen, Heiko T.; Kirby, John D.; Cooke, Paul S.; Arambepola, Niromi; Iwamoto, Gary A.

In: Physiology and Behavior, Vol. 90, No. 5, 23.04.2007, p. 771-781.

Research output: Contribution to journalArticle

Jansen, Heiko T. ; Kirby, John D. ; Cooke, Paul S. ; Arambepola, Niromi ; Iwamoto, Gary A. / Impact of neonatal hypothyroidism on reproduction in the male hamster, Mesocricetus auratus. In: Physiology and Behavior. 2007 ; Vol. 90, No. 5. pp. 771-781.
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