Novel expression of resistin in rat testis: functional role and regulation by nutritional status and hormonal factors.
Resistin, a recently cloned adipose-secreted factor, is primarily involved in the modulation of insulin sensitivity and adipocyte differentiation. However, additional metabolic or endocrine functions of this molecule remain largely unexplored. In this study, a series of experiments were undertaken to explore the potential expression, regulation and functional role of this novel adipocytokine in rat testis. Resistin gene expression was demonstrated in rat testis throughout postnatal development, with maximum mRNA levels in adult specimens. At this age, resistin peptide was immunodetected in interstitial Leydig cells and Sertoli cells within seminiferous tubules. Testicular expression of resistin was under hormonal regulation of pituitary gonadotropins and showed stage-specificity, with peak expression values at stages II-VI of the seminiferous epithelial cycle. In addition, testicular resistin mRNA was down-regulated by the selective agonist of PPARgamma, rosiglitazone, in vivo and in vitro. Similarly, fasting and central administration of the adipocyte-derived factor, leptin, evoked a significant reduction in testicular resistin mRNA levels, whereas they remained unaltered in a model of diet-induced obesity. From a functional standpoint, resistin, in a dose-dependent manner, significantly increased both basal and choriogonadotropin-stimulated testosterone secretion in vitro. Overall, our present results provide the first evidence for the expression, regulation and functional role of resistin in rat testis. These data underscore a reproductive facet of this recently cloned molecule, which may operate as a novel endocrine integrator linking energy homeostasis and reproduction.
Nogueiras
Ruben
R
Department of Physiology, University of Santiago de Compostela, c/San Francisco s/n, 15705, Spain.
Barreiro
M Luz
ML
Caminos
Jorge E
JE
Gaytán
Francisco
F
Suominen
Janne S
JS
Navarro
Victor M
VM
Casanueva
Felipe F
FF
Aguilar
Enrique
E
Toppari
Jorma
J
Diéguez
Carlos
C
Tena-Sempere
Manuel
M
D017667:Adipocytes / Q000166:cytology; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D015139:Blotting, Southern; D001835:Body Weight; D002454:Cell Differentiation; D015536:Down-Regulation; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D005508:Food Deprivation; D005786:Gene Expression Regulation; D006062:Gonadotropins / Q000378:metabolism; D006729:Hormones, Ectopic / Q000096:biosynthesis*; D007016:Hypophysectomy; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism; D007985:Leydig Cells / Q000378:metabolism; D008297:Male; D051379:Mice; D008820:Mice, Obese; D047495:PPAR gamma / Q000378:metabolism / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D052243:Resistin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077154:Rosiglitazone; D012708:Sertoli Cells / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D045162:Thiazolidinediones / Q000494:pharmacology; D013997:Time Factors; D014665:Vasodilator Agents / Q000494:pharmacology
D006062:Gonadotropins; D006729:Hormones, Ectopic; D007328:Insulin; D047495:PPAR gamma; D012333:RNA, Messenger; D052243:Resistin; C499623:Retn protein, mouse; C499622:Retn protein, rat; D045162:Thiazolidinediones; D014665:Vasodilator Agents; D000077154:Rosiglitazone; D005640:Follicle Stimulating Hormone