Neonatal hypothyroidism permanently alters follicle-stimulating hormone and luteinizing hormone production in the male rat

John D. Kirby, Niromi Arambepola, Tarja Porkka-Heiskanen, Yvonne K. Kirby, Marsha L. Rhoads, Hiroaki Nitta, Amy E. Jetton, Gary Iwamoto, Gary L. Jackson, Fred W. Turek, Paul S. Cooke

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Transient neonatal hypothyroidism, induced with the goitrogen 6-n- propyl-2-thiouracil (PTU), results in dramatic increases in both testis size and sperm production in the adult rat. The observed increases in testis size and function occur in the presence of normal circulating testosterone levels. However, circulating gonadotropin levels are chronically reduced by 30-50% at all times in treated males. To better understand the permanent reduction in serum gonadotropin levels following transient neonatal hypothyroidism, we conducted a series of experiments to evaluate pituitary and hypothalamic function in the adult male PTU-treated rat. PTU treatment led to a significant reduction in GnRH-stimulated LH production. Castration resulted in 3.9- to 8.5-fold increases in circulating gonadotropin levels in both treated and control males; however, the absolute increases were significantly reduced in treated males. In contrast to circulating levels, pituitary gonadotropin contents did not increase in treated males after castration. PTU treatment did not lead to a reduction in the density of either luteotropes or folliculotropes, and both cell types increased in size and density after castration. The relative concentrations of both gonadotropin β-subunit messenger RNAs increased more slowly in treated males than in controls after castration. Thus, although treated rats have the intrinsic ability to produce normal circulating levels of LH and FSH, gonadal feedback and an overall reduction in gonadotrope synthetic ability combine to produce the chronically reduced circulating levels of these hormones.

Original languageEnglish (US)
Pages (from-to)2713-2721
Number of pages9
JournalEndocrinology
Volume138
Issue number7
DOIs
StatePublished - 1997

Fingerprint

Follicle Stimulating Hormone
Luteinizing Hormone
Hypothyroidism
Thiouracil
Gonadotropins
Castration
Testis
Pituitary Gonadotropins
Antithyroid Agents
Propylthiouracil
Orchiectomy
Gonadotropin-Releasing Hormone
Testosterone
Spermatozoa
Hormones
Messenger RNA
Serum

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Kirby, J. D., Arambepola, N., Porkka-Heiskanen, T., Kirby, Y. K., Rhoads, M. L., Nitta, H., ... Cooke, P. S. (1997). Neonatal hypothyroidism permanently alters follicle-stimulating hormone and luteinizing hormone production in the male rat. Endocrinology, 138(7), 2713-2721. https://doi.org/10.1210/en.138.7.2713

Neonatal hypothyroidism permanently alters follicle-stimulating hormone and luteinizing hormone production in the male rat. / Kirby, John D.; Arambepola, Niromi; Porkka-Heiskanen, Tarja; Kirby, Yvonne K.; Rhoads, Marsha L.; Nitta, Hiroaki; Jetton, Amy E.; Iwamoto, Gary; Jackson, Gary L.; Turek, Fred W.; Cooke, Paul S.

In: Endocrinology, Vol. 138, No. 7, 1997, p. 2713-2721.

Research output: Contribution to journalArticle

Kirby, JD, Arambepola, N, Porkka-Heiskanen, T, Kirby, YK, Rhoads, ML, Nitta, H, Jetton, AE, Iwamoto, G, Jackson, GL, Turek, FW & Cooke, PS 1997, 'Neonatal hypothyroidism permanently alters follicle-stimulating hormone and luteinizing hormone production in the male rat', Endocrinology, vol. 138, no. 7, pp. 2713-2721. https://doi.org/10.1210/en.138.7.2713
Kirby, John D. ; Arambepola, Niromi ; Porkka-Heiskanen, Tarja ; Kirby, Yvonne K. ; Rhoads, Marsha L. ; Nitta, Hiroaki ; Jetton, Amy E. ; Iwamoto, Gary ; Jackson, Gary L. ; Turek, Fred W. ; Cooke, Paul S. / Neonatal hypothyroidism permanently alters follicle-stimulating hormone and luteinizing hormone production in the male rat. In: Endocrinology. 1997 ; Vol. 138, No. 7. pp. 2713-2721.
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