Bhagavatapurana 3.12.45

3.12.45

tasyoṣṇig āsīl lomabhyo gāyatrī ca tvaco vibhoḥ /
triṣṭum māṃsāt snuto 'nuṣṭub jagaty asthnaḥ prajāpateḥ //

45 & 46. The Ushnik metre issued from His hair, Gayatri from his skin, Trishtup from His flesh, Anushtup from His tendons, Jagati from the bones of Prajapathi, Pankti from his marrow, Brihati from His prana (the vital breath); the five clases of consonants were formed out of his Jiva (Life) and swaras (vowels) formed His body.