The invention provides recombinant forms of piscine follicle-stimulating hormone (FSH) with characteristic intramolecular disulfide bonds and modified glycosylation patterns in the .beta.-subunit that enhance the stability and metabolic activity of the hormone. Also provided are recombinant materials to produce the FSH .beta. and glycoprotein .alpha.-subunits singly or in combination to obtain complete heterodimeric hormone of regulated glycosylation pattern. The piscine FSH agonists of the invention are therapeutically useful to expedite the onset of puberty in captive fish and to alleviate reproductive dysfunctions in fish. Likewise, the piscine FSH antagonists of the invention will be therapeutically useful to halt gonadal development, thereby contributing to body weight gain of the fish,