Regulation of pituitary cell function by adiponectin.
Adiponectin is a member of the family of adipose tissue-related hormones known as adipokines, which exerts antidiabetic, antiatherogenic, antiinflammatory, and antiangiogenic properties. Adiponectin actions are primarily mediated through binding to two receptors expressed in several tissues, AdipoR1 and AdipoR2. Likewise, adiponectin expression has been detected in adipocytes as well as in a variety of extra-adipose tissues, including the chicken pituitary. Interestingly, adiponectin secretion and adiponectin receptor expression in adipocytes have been shown to be regulated by pituitary hormones. These observations led us to investigate whether adiponectin, like the adipokine leptin, regulates pituitary hormone production. Specifically, we focused our analysis on somatotrophs and gonadotrophs because of the relationship between the control of energy metabolism, growth and reproduction. To this end, the effects of adiponectin on both GH and LH secretion as well as its interaction with major stimulatory regulators of somatotrophs (ghrelin and GHRH) and gonadotrophs (GnRH) and with their corresponding receptors (GHS-R, GHRH-R, and GnRH-R), were evaluated in rat pituitary cell cultures. Results show that adiponectin inhibits GH and LH release as well as both ghrelin-induced GH release and GnRH-stimulated LH secretion in short-term (4 h) treated cell cultures, wherein the adipokine also increases GHRH-R and GHS-R mRNA content while decreasing that of GnRH-R. Additionally, we demonstrate that the pituitary expresses both adiponectin and adiponectin receptors under the regulation of the adipokine. In sum, our data indicate that adiponectin, either locally produced or from other sources, may play a neuroendocrine role in the control of both somatotrophs and gonadotrophs.
Rodriguez-Pacheco
Francisca
F
Department of Cell Biology, Physiology and Immunology, University of Córdoba, E-14014 Córdoba, Spain.
Martinez-Fuentes
Antonio J
AJ
Tovar
Sulay
S
Pinilla
Leonor
L
Tena-Sempere
Manuel
M
Dieguez
Carlos
C
Castaño
Justo P
JP
Malagon
María M
MM
D052242:Adiponectin / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects; D013006:Growth Hormone / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology* / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D054440:Receptors, Ghrelin; D018013:Receptors, Neuropeptide / Q000235:genetics; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics
D052242:Adiponectin; D012333:RNA, Messenger; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; C504339:adiponectin receptor 1, rat; C506573:adiponectin receptor 2, rat; D007986:Luteinizing Hormone; D013006:Growth Hormone; C048250:somatotropin releasing hormone receptor