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

HARNICHAR AE; ZUBIRIA G; PORTALES A; REY MA; SPINEDI E; GIOVAMBATTISTA A

Orlando

Congreso; 2017 ENDO Meeting; 2017

ESO

It is well known thatandrogens modulate adipose tissue (AT) distribution and function. Testosterone (T)has been shown that inhibit white adipocyte differentiation, however, verylittle is known about the effects on beige adipocytes. The purpose of thisstudy was to evaluate the effect of androgens on the thermogenic activity of retroperitonealAT (RPAT). For this aim three experimental groups of rats (Sprague-Dawley) wereused: control (CTR), pre-pubertally orchidectomized (ppODX) and pair-fedcontrol (CTR-PF). ppODX animals showed a decrease in bodyweight and food intake compared to CTR (P<0.05) and similar to CTR-PF.At age 60 days the RPAT from the different groups were dissected, weighed and processedfor histological analysis and UCP-1 quantification (RT-PCR). In additionalexperiments, RPAT adipocyte precursor cells (APCs) from different groups wereisolated and cultured up to confluence, then cells were induced todifferentiate (3 days) with a pro-browning cocktail. On differentiation day 8,cells were processed to quantify UCP-1. In addition, APCs from adult CTR ratswere isolated and differentiated with a pro-browning cocktail in the absence orpresence of 0.1 µM T [basal (B) or T, respectively]; thereafter cells remainedin culture medium without or with T. On differentiation day 8, 10 µM forskolin(FSK) was added for 4 hs to subsets of B and T cells: B without FSK (B-B), Bwith FSK (B-FSK), T without FSK (T-B), T with FSK (T-FSK). Cells were thenprocessed to quantify UCP-1. Androgen depletion induces a decrease in RPAT massin 60 days old rats (P<0.05, ppODX vs CTR and CTR-PF). On the other hand,UCP-1 gene expression in RPAT from ppODX rats was high (p<0.05, ppODX vs CTRand CTR-PF). Histological analysis indicated the presence of small adipocytesin RPAT from ppODX rats (p<0.05, ppODX vs CTR and CTR-PF) and the appearanceof multivacuolar, beige-like adipocytes. APCs from ppODX animals, when in vitrodifferentiated, showed a higher expression of UCP-1 indicating greater predispositionto generate beige adipocytes (p<0.05, ppODX vs CTR and CTR-PF). When evaluatedthe T direct (in vitro) effect, wefound a decreased UCP-1 expression in differentiated adipocytes (p<0.01, T-Bvs B-B). As expected, FSK increased UCP-1 gene expression in RPAT adipocytes (p<0.01,B-B vs B-FSK and T-B vs T-FSK,). However, FSK-induced UCP-1 expression was lowin T-treated cells (p<0.01, T-FSK vs B-FSK). This inhibition of UCP-1expression in T-treated cells was prevented when cells were co-incubated withan androgen receptor antagonist (Flutamide, F). We conclude that T could bemodulating the thermogenic program of beige adipocytes from RPAT by regulatingUCP-1 gene expression. (PIP 0198; FPREDM052015)