Patterns of pulsatile pituitary glycoprotein secretion in central hypothyroidism and hypogonadism

Mary Samuels, K. Lillehei, B. K. Kleinschmidt-Demasters, J. Stears, E. C. Ridgway

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Abstract

Five patients with central hypothyroidism and hypogonadism due to mass or infiltrative lesions of the pituitary and hypothalamus were studied to determine pulsatile pituitary glycoprotein secretion patterns. Blood samples were obtained every 15 min over 24 h, and TSH, LH, and FSH were measured by immunoradiometric assays. Hormone pulses were located by cluster analysis, and pulse patterns were compared to those in normal subjects. Three patients had unmeasurable LH levels, while two had a normal number of low amplitude pulses. In contrast, all patients had normal FSH pulse frequency, and only one had low pulse amplitude. Three patients had normal 24-h TSH pulse frequency and amplitude, while two had slightly decreased pulse parameters. However, all failed to show normal nocturnal increases in TSH pulse amplitude. Thus, anatomical hypothalamic-pituitary lesions disrupt pulsatile glycoprotein secretion in a discordant fashion. LH is most severely affected, with abnormal pulse patterns similar to those in idiopathic central hypogonadism. FSH and TSH pulses are relatively preserved, but loss of the usual nocturnal increase in TSH pulse amplitude is sufficient to cause clinical hypothyroidism. Whether these defects reflect intrinsic pituitary disease or impaired hypothalamic releasing factor function remains to be determined.

Original languageEnglish (US)
Pages (from-to)391-395
Number of pages5
JournalJournal of Clinical Endocrinology and Metabolism
Volume70
Issue number2
Publication statusPublished - 1990
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

Cite this

Samuels, M., Lillehei, K., Kleinschmidt-Demasters, B. K., Stears, J., & Ridgway, E. C. (1990). Patterns of pulsatile pituitary glycoprotein secretion in central hypothyroidism and hypogonadism. Journal of Clinical Endocrinology and Metabolism, 70(2), 391-395.