PROTEIN HORMONES AS LOCAL REGULATORS IN H UMAN OVARIES

Protein Hormones as Local Regulators in Human Ovaries: The classical c oncept of ovarian function regarding the ovary as the source of ova an d of steroid hormones that is controlled by hypophyseal hormones has r ecently been expanded by a system of local factors involved in ovarian regulation. Based on increasing evidence that ovarian regulation invo lves a complex system of putative para/autocrine factors, we investiga ted the local expression of protein hormones, with emphasis on differe nces between pre-and post-menopause. Using the molecular biology techn iques of reverse transcription-polymerase chain reaction (RT-PCR) and restriction endonuclease analyses of the generated PCR-products, we de tected transcripts of the prolactin (PRL) gene as well as of the place ntal lactogen (PL-A/ B)>growth hormone (GH-N) genes, all of which are members of the human GH/PL gene cluster. This expression patern of GH/ PL genes, found in both pre-and post-menopausal human ovaries, sets i t apart from those of the pituitary and placenta. In the human immune system it has been convincingly demonstrated that prolactin (PRL) and growth hormone (GH), in addition to exerting endocrine effects, regula te the lymphocyte response by paracrine and autocrine mechanisms. In e xtension of this concept we found, apart from well known endocrine con trol of ovarian reproductive function by these hormones, a local expre ssion of genes coding for protein hormones and their receptors in huma n ovaries. Particularly ovarian-derived GH-N and PL-A/B could be the m issing link in a well estabilshed local cascade of GHRH, GHRH-receptor , GH-receptor, IGF-I and IGF-I receptor as a putative para/autocrine r egulator of ovarian reproductive function.