Adiponectin and its receptors are expressed in the chicken testis: influence of sexual maturation on testicular ADIPOR1 and ADIPOR2 mRNA abundance

Abstract

Adiponectin is an adipokine hormone that influences glucose utilization, insulin sensitivity, and energy homeostasis by signaling through two distinct receptors, ADIPOR1 and ADIPOR2. While adipose tissue is the primary site of adiponectin expression in the chicken, we previously reported that adiponectin and its receptors are expressed in several other tissues. The objectives of the present study are to characterize adiponectin, ADIPOR1, and ADIPOR2 expressions in the chicken testis and to determine whether sexual maturation affects the abundance of testicular adiponectin, ADIPOR1, and ADIPOR2 mRNAs. By RT-PCR and nucleotide sequencing, testicular adiponectin, ADIPOR1, and ADIPOR2 mRNAs were found to be identical to that expressed in the abdominal fat pad. Using anti-chicken adiponectin, ADIPOR1, or ADIPOR2 antibodies and immunohistochemistry, adiponectin-immunoreactive (ir) and ADIPOR1-ir cells were found exclusively in the peritubular cells as well as in Leydig cells. However, ADIPOR2-ir cells were found in the adluminal and luminal compartments of the seminiferous tubules as well as in interstitial cells. In particular, Sertoli cell syncytia, round spermatids, elongating spermatids, spermatozoa, and Leydig cells showed strong ADIPOR2 immunoreactivity. Using quantitative real-time PCR analyses, testicular ADIPOR1 and ADIPOR2 mRNA abundance were found to be 8.3-and 9-fold higher (P!0.01) in adult chickens compared with prepubertal chickens respectively, suggesting that sexual maturation is likely to be associated with an up-regulation of testicular ADIPOR1 and ADIPOR2 gene expressions. Collectively, our results indicate that adiponectin and its receptors are expressed in the chicken testis, where they are likely to influence steroidogenesis, spermatogenesis, Sertoli cell function as well as spermatozoa motility.

Characterization of adiponectin concentrations and molecular weight forms in serum, seminal plasma, and ovarian follicular fluid from cattle

“…These results indicate that species differences may exist with regard to the specific ovarian response to AdipoQ. For male reproduction, the AdipoQ protein was localized in the peritubular cells and Leydig cells of the chicken testis [15]. The Leydig cells were also positive for AdipoQ in the rat testis [16].…”

“…Adiponectin expression is less responsive to gonadotropins than metabolic signals, suggesting a function of AdipoQ as the endocrine integrator linking metabolism and gonadal function [16]. AdipoR1 and AdipoR2 mRNA were observed in several testicular cell types and were higher in adult versus prepubertal chickens [15]. Androgens, particularly testosterone, are inversely related to the serum AdipoQ concentrations in humans [17] and mice [18], and treatment with recombinant AdipoQ inhibits testosterone secretion ex vivo [16].…”

Ghrelin affects stopover decisions and food intake in a long-distance migrant

“…The role of leptin in birds has been hotly debated in the past (71)(72)(73)(74), and the presence of this hormone in the avian circulation has not been convincingly demonstrated (71,(75)(76)(77). Adiponectin, orexin, and obestatin have been studied only at the level of gene cloning or gene expression, but few functional data are available (78)(79)(80)(81)(82). Thus, the present study represents a break-through with regard to the role of appetite-stimulating or -suppressing hormones as physiological modulators of stopover decisions during migration.…”

Obesity Associated Adipocytokines in Girls with Premature Thelarche

“…Cinsel olgunlaşmanın testiküler AdipoR1 ve R2 up-regülasyonu ile ilişkili olduğu ve steroidogenez, spermatogenez, Sertoli hücre fonksiyonu ve sperm hareketliliğini etkilediği belirtilmiştir. 33 İlk kez PT hastalarında adiponektin düzeyleri ile atropometrik parametrelerin birlikte değer-lendirildiği çalışmamızda BKİ'den bağımsız olarak PT'li hastalarda istatistiksel olarak anlamlı olmayan hafif yüksek plazma adiponektin seviyeleri saptanmıştır. Hafif artış saptanan bu adiponektin düzeylerinin azalan leptin düzeylerine karşı gelişen bir mekanizmaya bağlı olabileceği düşünülmektedir.…”