Dependence of calcium on thyroid hormone for the regulation of cellular functions

  • AM Kemalkolam University of Jos, Jos, PMB 2084, Jos Nigeria
  • Sabo University of Jos, Jos, PMB 2084, Jos Nigeria
  • ABA Adelaiye University of Jos, Jos, PMB 2084, Jos Nigeria
  • AS Sagay University of Jos, Jos, PMB 2084, Jos Nigeria

Abstract

Recently, the thyroid hormone has been shown to cause increase in Ca2+concentration by mobilizing intracellular Ca2+. The mobilization of intracellular Ca2+in the absence of transmembrane Ca2+influx has been accepted as evidence for a cell-surface Ca2+ - receptor. The possible role of thyroid hormone in the regulation of cellular functions by Ca2+-channel was investigated using parameters proven to indispensably involve Ca2+: Bleeding and clotting times and rat uterine muscle activity in Ca2+-free Tyrode's solution. Adult female Wistar rats divided into four groups, namely; (i) Control, (ii) Thyroidectomized, (iii) Throidectomized-treated with thyroxine and (iv) Thyroxinetreated; were fed on rat chow. While groups i and ii were allowed access to tap water ad libitum for 60 days, groups iii and iv received tyroxine (10mg/kg body weight) every alternate day and tap water ad libitum for 60 days. All groups were kept in an air-conditioned room till they were euthanized. The results showed that thyroxine elicited biphasic contraction in Ca2+- depletion and potentiated uterine contraction during Ca2+ - loading (P<0.001). Inhibition of contractions in thyroidectomy, showed dependency of Ca2+on thyroid hormones for the regulation of cellular functions.

Keywords: thyroid hormones, calcium receptor, cellular functions

Nigerian Journal of Physiological Sciences Vol. 20(1&2) 2005: 95-100
Published
2006-07-13
Section
Articles

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eISSN: 0794-859X