Strain specific analysis of Gpr75 gene expression in B-Gpr75 KO mice by RT-qPCR. Brain was collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-Gpr75 KO mice (-/-) (n=1). B-Gpr75 KO mice showed no detectable expression of mGpr75 mRNA.

Weight gain during high-fat diet and metabolic phenotype in male B-Gpr75 KO mice. (A) Biweekly body weight gain during a 10-week high-fat diet (HFD) challenge. (B) Changes in fasting blood glucose after the high-fat diet challenge. (C) Results of a glucose tolerance test at the end of the 10-week high-fat diet challenge. (D) Area under the curve (AUC) for the IPGTT. (E) Results of an insulin tolerance test at the end of the 10-week high-fat diet challenge. (F) Area under the curve (AUC) for the ITT. Results are presented as mean ±SEM. Abbreviations: ns, not statistically significant; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

B-Gpr75 KO mice on a high-fat diet showed no significant difference in body weight compared to the normal diet group.

Blood biochemistry tests of B-Gpr75 KO mice. Serum from the male C57BL/6 and homozygous B-Gpr75 KO mice (n=8) was collected and analyzed for levels of blood biochemistry. There were no significant differences in ALT and AST levels between groups. After a high-fat diet, the level of TC significantly increased. The TG levels did not change significantly in the other groups, except in the B-Gpr75 KO mice. Values are expressed as mean ± SEM. Abbreviations: ns, not statistically significant; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

Body fat content and liver coefficient of high-fat diet in B-Gpr75 KO mice. After 10 weeks of high-fat induction in male C57BL/6 and B-Gpr75 KO mice (n=8), the epididymal adipose tissue, inguinal adipose tissue, and liver were weighed. The weight of fat in C57BL/6 mice after high-fat induction was significantly higher than that in the Chow group. In the B-Gpr75 KO mice, there were no significant differences in these indicators following high-fat diet induction, except for liver weight. Values are expressed as mean ± SEM. Abbreviations: ns, not statistically significant; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.