Hyperthecosis

Abstract: Summary OBJECTIVE Recent studies have suggested that androgen secretion by ovarian virllizing tumours may be gonadotrophin dependent. The aim of this study was to investigate the suppressive effect of GnRH agonist administration on androgen secretion. In women with such tumours. DESIGN AND PATIENTS A single 1.m. Injection Of D-Trp-6-GnRH (GnRHa), 3·75 mg, was given to five unrelated patients referred for clinical symptoms of virilization with plasma testosterone (T) levels greater than 7 nmol/l but with normal dehydroeplandrosterone sulphate (DHEAS) levels. Diagnoses of adrenal tumour or a non-classical 21-hydroxylase deficiency were screened for by the dexamethasone suppression test, ACTH stimulation test and adrenal CT scanning, and were ruled out in all patients. The one premenopausal patient received cyproterone acetate in a dose of 50 mg twice dally for 3 weeks, starting 1 week before GnRHa administration. MEASUREMENT Testosterone, androstenedione (A), DHEAS, 17-hydroxyprogesterone (OHP), LH and FSH plasma concentrations were measured by radioimmunoassay of blood samples taken before and 3 weeks after GnRHa. RESULTS In each patient, GnRHa suppressed gonadotrophin levels and reduced T and A to the range for normal control women. With these results, and because accurate localization of an ovarian androgen secreting tumour could not be achieved by pelvic ultrasonography and CT scanning, exploratory laparotomy was undertaken. A Sertoll-Leydig cell tumour was found in the premenopausal patient, and granulosa cell tumour, hllus cell tumour and two hyperthecoses in the four post-menopausal patients. After bilateral ovarlectomy and hysterectomy in the post-menopausal woman and after unilateral ovarlectomy in the premenopausal women, androgen levels were normalized. CONCLUSIONS In virllized women, the findings of Increased serum testosterone with normal gonadotrophin levels and GnRHa suppression of gonadotrophins leading to normalization of testosterone levels, suggest that various ovarlan androgen-secreting tumours, as well as hyperthecosis, are not autonomous but apparently depend upon continuous gonadotrophin stimulation.

Abstract: Ovarian theca cells are the predominant source of gonadotropin-stimulated androgen biosynthesis in vivo. Troglitazone (TG), a synthetic agonist of the peroxisome proliferator-activated receptor g (PPARg) and a thiazolidinedione used to treat insulin resistance, decreases serum androgen concentrations in women with hyperthecosis and/or polycystic ovary syndrome. Using reverse transcription-polymerase chain reaction (RT-PCR), we demonstrated the presence of PPARg mRNA in the porcine ovary. Since activation of ovarian PPARg may alter hormonestimulated steroidogenesis in vitro, we cultured porcine theca cells for 48 h in the presence of two different PPARg ligands, TG and 15-deoxy-D12,14-prostaglandin J2 (15d-PGJ2). Putative TGmediated activation of PPARg resulted in a 53%‐69% decrease in LH- and/or insulin-stimulated androstenedione and testosterone accumulation. Although TG reduced 3-isobutylmethylxanthine-enhanced LH-stimulated cAMP accumulation by 74%‐ 78%, it did not alter basal cAMP concentrations. Exposure to 8Br-cAMP did not overcome the TG-induced inhibition of androgen accumulation. In contrast, TG administration amplified basal and hormone-stimulated progesterone accumulation, particularly in the presence of insulin, without altering levels of 17a-hydroxyprogesterone. The putative natural PPARg ligand, 15d-PGJ2, inhibited androgen biosynthesis and stimulated progesterone production. RT-PCR-based amplification of cytochrome P450 cholesterol side-chain cleavage (CYP11A) and cytochrome P450 17a-hydroxylase/C-17,20-lyase (CYP17) transcripts indicated that TG moderately enhanced expression of these genes. However, TG did not affect CYP17 protein expression. We conclude that putative ligand-mediated activation of PPARg decreases LH- and/or insulin-driven theca cell androgen production by impairing the ability of CYP17 to synthesize androstenedione from available progestins. The corresponding augmentation of progesterone production could suggest that PPARg activation induces theca cell differentiation toward a progestinsynthesizing phenotype. gene regulation, mechanisms of hormone action, ovary, steroid hormones, theca cells