Hypophyseal-portal somatostatin (SRIH) and jugular venous growth hormone secretion in the conscious unrestrained ewe

Abstract

Somatostatin (SRIH) release into hypophyseal portal blood varies reciprocally with growth hormone (GH) pulse generation in the male rat. However, few studies have directly evaluated this relationship in the female of any species. To address this issue, we carried out intensive (5 min) and extended (240 min) simultaneous monitoring of hypophyseal portal SRIH and internal jugular GH secretion in 7 unanesthetized ewes. Bihormonal synchrony was assessed by three statistically independent but complementary analyses: (i) cross-approximate entropy (X-ApEn) analysis to appraise the conditional regularity of SRIH/GH release patterns; (ii) cross-correlation analysis of paired sample SRIH and GH releas..