Muon Capture and the Hypothesis of Partially Conserved Axial-Vector Current

We present the results of a new calculation of the muon-capture rates in hydrogen and He³, with special emphasis on the estimate of the induced pseudoscalar form factor FP. Two values of FP based on the Nambu and the Gell-Mann-L\'evy versions of the PCAC hypothesis are given, and the corresponding capture rates are compared with experimental data.