Atrial natriuretic peptide in bovine corpus luteum

Atrial natriuretic peptide (ANP) has been demonstrated to exert endocrine functions, including the modulation of steroid synthesis. This prompted investigations to search for ANP receptors in the corpus luteum, a tissue that produces progesterone. The studies revealed a single binding site for [125I] ANP with similar characteristics (Kd, 122 pM; maximum binding, 18 fmol/mg protein) in all four stages of corpus luteum development. These receptors were demonstrated to stimulate cGMP production upon activation with synthetic ANP. Maximal cGMP synthesis was observed at 10(-7) M ANP, 5 min after activation of receptors. An acidic extract of corpus luteum contained immunoreactive ANP (approximately 220 fmol/g tissue), as indicated by gel chromatography, HPLC, and identification by means of a highly specific ANP antibody. The data do not permit definition of a specific endocrine role of ANP in the corpus luteum.