Ghrelin, an endogenous ligand for the growth hormone-secretagogue receptor, is expressed in the human adrenal cortex.
Ghrelin is an endogenous ligand of the growth hormone secretagogue receptor (GHS-R), which was originally isolated from rat stomach. Ghrelin and GHS-R are also expressed in several peripheral tissues, including adrenal glands, and this prompted us to study ghrelin expression and ghrelin-binding site localization in the human adrenal cortex, and the possible effect of this peptide on corticosteroid-hormone secretion. Reverse transcription-polymerase chain reaction (RT-PCR) and radioimmune assay (RIA) showed sizeable expression of ghrelin mRNA and protein in six human adrenal cortexes. Autoradiography evidenced abundant [125I]ghrelin binding sites in the adrenal zona glomerulosa and outer zona fasciculata. However, ghrelin (10(-6) M) did not significantly affect either basal or agonist (ACTH and angiotensin-II)-stimulated early and late steps of steroid-hormone synthesis from adrenocortical slices (as measured by quantitative high pressure liquid chromatography). Since zona glomerulosa is the cambium layer involved in the growth maintenance of adrenal cortex, the present coupled RT-PCR, RIA and autoradiographic findings could suggest the involvement of ghrelin in the autocrine-paracrine regulation of human adrenal growth.
Tortorella
Cinzia
C
Department of Human Anatomy and Physiology, Section of Anatomy, University of Padua, I-35121 Padua, Italy.
Macchi
Carlo
C
Spinazzi
Raffaella
R
Malendowicz
Ludwik K
LK
Trejter
Marcin
M
Nussdorfer
Gastone G
GG
D015069:18-Hydroxycorticosterone / Q000378:metabolism; D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D001345:Autoradiography / Q000379:methods; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D003345:Corticosterone / Q000378:metabolism; D003350:Cortodoxone / Q000378:metabolism; D003900:Desoxycorticosterone / Q000378:metabolism; D054439:Ghrelin; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D066298:In Vitro Techniques; D008024:Ligands; D008875:Middle Aged; D036361:Peptide Hormones / Q000235:genetics / Q000378:metabolism*; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D020133:Reverse Transcriptase Polymerase Chain Reaction
D054439:Ghrelin; D008024:Ligands; D036361:Peptide Hormones; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D000804:Angiotensin II; D003900:Desoxycorticosterone; D011374:Progesterone; D015069:18-Hydroxycorticosterone; D011284:Pregnenolone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone; D003350:Cortodoxone; D006854:Hydrocortisone