Testosterone Inhibits the Thermogenic Program in Beige Adipocytes from Retroperitoneal Adipose Tissue

HARNICHAR ALEJANDRO EZEQUIEL; ZUBIRÍA, MARÍA GUILLERMINA; PORTALES, ANDREA; REY, M. AMANDA; SPINED, EDUARDO; GIOVAMBATTISTA, ANDRÉS

Orlando

Congreso; ENDO 2017; 2017

It is well known that androgens modulate adipose tissue (AT)distribution and function. Testosterone (T) has been shown that inhibit whiteadipocyte differentiation, however very little is known about the effects onbeige adipocytes. The purpose of this study was to evaluate the effect ofandrogens on the thermogenic activity of retroperitoneal AT (RPAT). For thisaim three experimental groups of male rats (Sprague-Dawley) were used: control(CTR), pre-pubertally orchidectomized (ODX) and pair-fed control (CTR-PF). ODXanimals showed a decrease in body weight and food intake compared to CTR (P<0.05)and similar to CTR-PF. At 60 days old the RPAT from the different groups weredissected, weighed and processed for histological analysis and UCP-1quantification (RT-PCR). In additional experiments, adipocyte precursor cells(APCs) APCs from different groups were isolated and cultured up to confluence,then cells were induced to differentiate (3 days) with a pro-browning cocktail.On differentiation day 8, cells were processed to quantify UCP-1. In addition,APCs from adult CTR rats were isolated and differentiated with a pro-browningcocktail in the absence or presence of 0.1 µM T (basal (B) or T, respectively);thereafter cells remained in culture medium without or with T. Ondifferentiation day 8, 10 µM forskolin (FSK) was added for 4 hs to subsets of Bor T cells: B without FSK (B-B), B with FSK (B-FSK), T without FSK (T-B), Twith FSK (T-FSK). Cells were then processed to quantify UCP-1. Androgendepletion induces a decrease in RPAT mass from 60 days old rats (p<0.05 ODXvs CTR and CTR-PF). On the other hand, UCP-1 gene expression in RPAT from ODXrats was high (p<0.05, ODX vs CTR and CTR-PF). Histological analysisindicated the presence of small adipocytes in RPAT from ODX rats (p<0.05,ODX vs CTR and CTR-PF) and the appearance of multivacuolar, beige-likeadipocytes. APCs from ODX animals, when were differentiated in vitro, showed ahigher expression of UCP-1 indicating greater predisposition to generate beigeadipocytes (p<0.05, ODX vs CTR and CTR-PF). When we evaluated the directeffect of T in vitro, we found a decrease in UCP-1 expression indifferentiated adipocytes (p<0.01, T-B vs B-B). As expected, FSK increasedUCP-1 gene expression in RPAT adipocytes (p<0.01, B-B vs B-FSK and T-B vsT-FSK). However, FSK-induced UCP-1 expression was low in T-treated cells(p<0.01, T-FSK vs B-FSK). This inhibition of UCP-1 expression in T-treatedcells was prevented when cells were co-incubated with an androgen receptorantagonist (Flutamide, F, 1 µM). We conclude that T could be modulating thethermogenic program of beige adipocytes from RPAT by regulating UCP-1 geneexpression