An isolated stage one oocyte from sturgeon. The stage one germ cell is isolated from stage II ovaries and incubated with trypsin and collagenase and either PBS, Hank’s balanced salt solution or Leibovitz medium. The suspension was then filtered and centrifuged to obtain early previtellogenic oocytes. The primary stage previtellogenic oocytes may be used in a cosmetic composition, nutritional composition or a nutraceutical composition. The early previtellogenic oocytes may be produced by the induction of differentiation of primordial germ cells. Also disclosed are immortalised sturgeon primordial germ cells, and immortalised sturgeon germ cells, such as stage 1 oocytes, stage 2 oocytes, stage 3 oocytes, stage 4 oocytes, stage 5 oocytes, and spermatozoa. Extracts, cosmetics, nutritional products and nutraceutical products are disclosed comprising any of these cell types. Also disclosed is production of sturgeon sperm by the induction of differentiation of primordial germ cells.