Consequences of tissue-specific lack of seipin in mouse male reproductive organs. (A) Distribution of adipose tissue in mouse models with ubiquitous-, germ cell-, or adipocyte-specific loss of seipin. Absence of the epididymal fat pad (arrowheads) near the testes (arrows) in S-KO and aS-KO but not gS-KO mice. (B and C) S-WT and aS-KO males express comparable levels of seipin in testis, whereas S-KO testis and seminiferous tubules of gS-KO males lack detectable seipin. (D) Percentage of sperm with abnormal morphology in controls and mice with tissue-specific deletion of seipin. **P ≤ 0.01; ***P ≤ 0.001. (E) Representative examples of abnormal morphology of sperm from S-KO and gS-KO males. (a) Normal sperm. (b–f) Head defects include lack of the (b) usual hook, (c) banana shape, or (d) apparent cavities. Tail defects include (b) folded sperm and (e) sheath defects (e). (f) Bundle-like masses of connected sperm. Arrows indicate morphological abnormalities.