Does Chronic Hyperglycemia Affect Female Rat Sexual Behavior? Differences in Paced and Non-Paced Mating

Introduction: Diabetes mellitus has been associated with sexual dysfunction; however, in women this relationship is controversial. A study using a model of type 2 diabetes mellitus (DM2) failed to find a reduced receptivity in the non-paced mating (NPM), but the appetitive aspects of female sexual behavior have not been evaluated, for example, in the paced mating (PM) paradigm. Aim: To evaluate all components of female sexual behavior (in NPM and PM) in a model of DM2 using ovariectomized (OVX) (treated with steroids) or intact female rats (non-OVX) in natural proestrus. Methods: Neonatal females (3e4 days) were administered streptozotocin (STZ, 70 mg/kg, intraperitoneally) or citrate buffer. At week 8, a glucose tolerance test was performed. At week 10, half of the females were OVX, and in the other half (non-OVX) the estrous cycle was monitored. At the twelfth week, the sexual behavior tests were conducted; OVX females were treated with estradiol benzoate (10 mu g, -24 hours) and progesterone (3 mg, -4 hours), whereas the non-OVX were evaluated on vaginal proestrus. Main Outcome Measures: We registered in NPM and PM receptivity (lordosis quotient and intensity), as well as the number of proceptive and aggressive behaviors. Additionally, in PM we calculated the percentage of exits and the return latencies after receiving stimulation and the time the female remained in the male's compartment. Results: The STZ-treated females presented glucose intolerance and were hyperglycemic. Neonatal STZ treatment provoked changes in the females' sexual behavior depending on the paradigm and the hormonal condition. In the NPM, STZ-OVX females had decreased lordosis quotient and intensity and increased aggression, whereas, in the STZ-non-OVX females, there was a decrease in proceptivity; such changes were not observed in PM. Regardless of whether the STZ-treated females were OVX, they failed to perform the pacing behavior. Clinical Implication: These data support the idea that chronic mild hyperglycemia, like that observed in DM2 (which represents 90% of the clinical cases), provokes marginal changes in most aspects of female sexual behavior. Strengths & Limitations: The main strength of this work is the evaluation of consummatory and motivational aspects of female sexual behavior in a model of DM2. The main limitation is the duration of the experimental design that does not resemble the course of the disease in humans. No histologic or biochemical analyses were performed. Conclusion: These results suggest that chronic hyperglycemia produces decreases in sexual behavior. Copyright (C) 2019, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.