RF36 | PMON301 The Local Androgen-Estrogen Environment Differentially Regulates Adipocyte Lipid Metabolism by Fat Depot and Sex
Authors: Faulkner Patricia , Ahmad Irshad , Kothmann Kadden , Laffitte Emily , Chau Laura , Grizzaffi Matthew , Acebo Sarah , Hernandez Daniel , Skenandore Cassandra , Browning Luke , Newell-Fugate Annie 
Published: November 2022

Obese men often have low blood testosterone (Test) levels yet may have high or low blood 17β-estradiol (E2) levels while showing an increased risk of type 2 diabetes. In contrast, women with polycystic ovary syndrome (PCOS) experience increased risk of visceral white adipose tissue (vWAT) deposition, insulin resistance, and cardiovascular disease. Overall, insulin resistance is correlated with hypoandrogenemia in males and hyperandrogenemia in females. The aim of the present study was to elucidate the sexually dimorphic role androgens play in regulating the adipocyte insulin signaling pathway. We hypothesized that androgens would upregulate insulin signaling pathway components in female vWAT adipocytes irrespective of E2 levels. We further hypothesized that androgens would downregulate insulin signaling pathway components in male vWAT adipocytes dependent on E2 levels. vWAT and subcutaneous white adipose tissue (scWAT) were collected from male and female rats, digested in sterile-filtered collagenase, and the resulting preadipocytes were proliferated to 80% confluence. After cell cultures were induced to a minimum of 60% adipocyte cells, cells were exposed to the following treatments: no steroid, 5a-dihydrotestosterone (DHT), E2, Test, fulvestrant, Test + letrozole, and Test + fulvestrant for 48 hours. Adipocyte protein was western blotted for Total AKT and p-AKTSer473 and normalized to GAPDH. qPCR was performed to quantify insulin receptor (Insr), insulin receptor substrate 1 (Irs1), protein kinase B isoform 2 (Akt2), fork head box protein 1 (Foxo1) using the housekeeping gene Gapdh. 48-hour steroid treatments of E2 reduced pAKTSer473: AKT compared with that of controls in male vWAT. Interestingly, pAKTSer473: AKT of E2-treated male scWAT was unchanged compared with control levels. Yet, for both male scWAT and vWAT, Test and fulvestrant treatments had greater pAKTSer473: AKT than in E2-treated cells, while T + letrozole-treated male scWAT also showed higher pAKTSer473: AKT than in E2 treatments. In contrast, T + fulvestrant increased pAKTSer473: AKT in female vWAT. Protein data for females and Foxo1 protein are still being generated. At the RNA level female scWAT had upregulated Insr in response to Test + fulvestrant and Akt2 and Foxo1 to Test+ fulvestrant. In both male and female vWAT fulvestrant upregulates the Insr. As we see differences in the Test, fulvestrant and letrozole treatments, the control of local androgens over insulin signaling in WAT may vary by local ERa and ERβ expression and/or steroidogenesis. Furthermore, estrogenic effects on insulin signaling seem to vary by fat depot in males. Thus, sex-specific pharmaceuticals targeting the intersection of androgens, estrogens, and AKT in WAT can be an important tool in the treatment of insulin resistance in obese patients.

Presentation: Monday, June 13, 2022 12:30 p.m. - 12:35 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.