TY - JOUR
T1 - Differential orderliness of the GH release process in castrate male and female rats
AU - Gevers, Evelien
AU - Pincus, Steve M.
AU - Robinson, Iain C.A.F.
AU - Veldhuis, Johannes D.
PY - 1998/2
Y1 - 1998/2
N2 - Male- and female-specific modes of episodic growth hormone (GH) release are presumptively imposed by sex steroid hormones, and, although typically evident visually, are vividly distinguished quantitatively via a regularity statistic, approximate entropy (ApEn), in both the rat and human. GH secretory patterns may determine GH-stimulated growth and specific hepatic and muscle gene expression in the rat. Consequently, it is important to discern mechanisms that underlie their regulation. Here we have examined the impact of prepubertal gonadal suppression (at 4 wk of age) via surgical or pharmacological [gonadotropin-releasing hormone (GnRH) agonist] intervention on the regularity (ApEn) of GH release in male and female rats (at 10-11 wk of age) sampled at 10-min intervals for 10 h (n = 60 points) during a lights- out (dark) period. We observed a graded hierarchy of mean disorderliness of GH release that was quantifiable by ApEn measures, with maximal to minimal disorderliness in the following rank order: intact female, GnRH agonist- treated female, ovariectomized female, orchidectomized male, GnRH agonist- treated male, and intact male. These observations suggest a continuum of sex steroid actions on the regularity of GH secretion and, by inference, on the interplay among GH-releasing hormone, somatostatin, and GH/insulin-like growth factor I negative feedback.
AB - Male- and female-specific modes of episodic growth hormone (GH) release are presumptively imposed by sex steroid hormones, and, although typically evident visually, are vividly distinguished quantitatively via a regularity statistic, approximate entropy (ApEn), in both the rat and human. GH secretory patterns may determine GH-stimulated growth and specific hepatic and muscle gene expression in the rat. Consequently, it is important to discern mechanisms that underlie their regulation. Here we have examined the impact of prepubertal gonadal suppression (at 4 wk of age) via surgical or pharmacological [gonadotropin-releasing hormone (GnRH) agonist] intervention on the regularity (ApEn) of GH release in male and female rats (at 10-11 wk of age) sampled at 10-min intervals for 10 h (n = 60 points) during a lights- out (dark) period. We observed a graded hierarchy of mean disorderliness of GH release that was quantifiable by ApEn measures, with maximal to minimal disorderliness in the following rank order: intact female, GnRH agonist- treated female, ovariectomized female, orchidectomized male, GnRH agonist- treated male, and intact male. These observations suggest a continuum of sex steroid actions on the regularity of GH secretion and, by inference, on the interplay among GH-releasing hormone, somatostatin, and GH/insulin-like growth factor I negative feedback.
KW - Entropy
KW - Growth hormone
KW - Pituitary
KW - Rodent
KW - Sex
UR - http://www.scopus.com/inward/record.url?scp=0031990840&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031990840&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.1998.274.2.r437
DO - 10.1152/ajpregu.1998.274.2.r437
M3 - Article
C2 - 9486302
AN - SCOPUS:0031990840
SN - 0363-6119
VL - 274
SP - R437-R444
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 2 43-2
ER -