Increased circulating levels of immunoreactive beta-endorphin in polycystic ovary syndrome is not caused by increased pituitary secretion.

Abstract

Our purpose was to investigate the source and role of elevated levels of immunoreactive beta-endorphin in polycystic ovary syndrome. We wished to determine whether immunoreactive beta-endorphin secretion in patients with polycystic ovary syndrome is influenced by body weight and whether the pituitary release of immunoreactive beta-endorphin with corticotropin-releasing hormone is related to luteinizing hormone levels or adrenal androgen secretion. Eighteen patients with polycystic ovary syndrome and 10 ovulatory controls were studied. Each subject received 1 microgram/kg intravenous corticotropin-releasing hormone and an oral glucose tolerance test on alternate days. Levels of plasma immunoreactive beta-endorphin, corticotropin, luteinizing hormone, cortisol, adrenal androgens, and insulin were measured. Although immunoreactive beta-endorphin levels were elevated in patients with polycystic ovary syndrome (p < 0.01), incremental responses after corticotropin-releasing hormone were similar to controls and were not influenced by body weight. Serum luteinizing hormone levels were not affected by corticotropin-releasing hormone and did not correlate with immunoreactive beta-endorphin levels. Adrenal androgen responses after corticotropin-releasing hormone were increased in patients with polycystic ovary syndrome (p < 0.01) but were not correlated with immunoreactive beta-endorphin secretion. After oral glucose was given, elevated fasting insulin levels increased significantly in patients with polycystic ovary syndrome (p < 0.01), as did immunoreactive beta-endorphin levels (p < 0.05). The increases in insulin and immunoreactive beta-endorphin levels were correlated (p < 0.05). Pituitary secretion of immunoreactive beta-endorphin is normal in patients with polycystic ovary syndrome, and pancreatic secretion appears to be increased. Corticotropin-releasing hormone does not influence luteinizing hormone levels, and adrenal androgen sensitivity is not influenced by immunoreactive beta-endorphin secretion.