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This paper describes the time course of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in two patients with the complete androgen insensitivity syndrome (AIS) during puberty and adolescence prior to gonadectomy. In early puberty, LH values were comparable to normal male as well as female standards. At the age of 17 and 18.7 years, respectively, a sudden rise in LH occurred just after the start of estradiol supplementation. These high LH concentrations in the late puberty of our patients are comparable to the values found during early puberty in castrated individuals and children with gonadal dysgenesis. In contrast, FSH concentrations continuously showed levels in the normal male or female range with no rise during adolescence. The sudden increase of LH in late puberty is most probably due to defective testosterone receptors in the pituitary/hypothalamus which apparently can no longer be suppressed by rising testosterone levels and an escape from the negative estradiol feedback. The role of estradiol supplementation might be incidental and further investigation into its role is needed. In contrast to the elevated levels of FSH in patients with defective spermatogenesis, FSH is normal in our patients with AIS and testes in situ. This indicates that FSH secretion is regulated by a combined action of estradiol and gonadal hormones like inhibin.

FSH and LH were functionally examined in 5 women with feminizing testis and compared with the peripheral sex steroid hormones. The oestradiol levels were found decreased, while those of testosteron were elevated. FSH disclosed no significant differences while the basal levels of LH and its stimulatory response to LH-RH were increased in the patients.

The effect of exogenous estrogens on luteinizing hormone release was studied in three siblings with complete testicular feminization syndrome. Two subjects, 21 and 20 years old, were postpubertal. The third, 15 years old, was in the early pubertal stage. An estrogen provocation test was performed in which 20 mg of conjugated estrogens were administered intravenously and serum follicle-stimulating hormone and luteinizing hormone levels were assessed every 12 hours for 96 hours under basal conditions, on day 5 of an eight-day treatment with 0.2 mg/day ethinyl estradiol orally, and on day 5 of a subsequent eight-day treatment with 0.2 mg/day ethinyl estradiol and 120 mg/day cyproterone acetate orally. The first two tests were repeated one month after gonadectomy. During pregonadectomy treatments there was an overall luteinizing hormone fall. After gonadectomy, the two postpubertal subjects exhibited luteinizing hormone surges during ethinyl estradiol treatment -in one as a single peak and in the other as multiple peaks. A positive feedback effect was not induced in the youngest patient either before or after gonadectomy as in normal prepubertal and early pubertal females. The data suggest that testosterone or some other testicular factor inhibits estrogen induced positive feedback for luteinizing hormone. This inhibition mechanism acts independently of the testosterone cytosol receptor.

Response of serum levels of gonadotropins and prolactin to doses of estrogen and progesterone was measured in a patient with the complete form of androgen insensitivity, ie, testicular feminization. Before gonadectomy a single 2.5-mg dose of estradiol benzoate (E2B) produced a decrease in gonadotropin levels. Gonadectomy resulted in a rise of serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) but had no effect on levels of prolactin. The following results were obtained after gonadectomy: During low-dosage therapy with ethinyl estradiol (EE) a single 2.5-mg dose of E2B produced a decrease in FSH and LH levels, no LH surge, and a small rise in prolactin levels. With a tenfold higher EE priming, the same dose of E2B provoked an LH surge; progesterone administration produced FSH, LH, and prolactin release. However, progesterone priming blocked the positive feedback of estradiol and enhanced its negative feedback. Pituitary sensitivity ot nonandrogenic steroids appears to be normal in cases of testicular feminization. Under this condition, after gonadectomy, the dynamics of gonadotropins and prolactin in response to estrogens or progesterone administration are similar to those in normal women and suggest that aromatization products of testosterone do not produce any irreversible effects on neuroendocrine differentiation of androgen-insensitive patients

Administration of opiate receptor antagonists augmented pulsatile LH release in six estrogen-treated, orchidectomized individuals with testicular feminization. In response to an opiate antagonist, LH pulse frequency increased from 3.0 +/- 0.55 (+/- SE) to 5.0 +/- 0.45 pulses/8 h (P = 0.034). Since these patients have inborn target tissue resistance to androgens, we infer that sustained androgen action is not obligatory to the emergence of endogenous inhibitory opiate tone in man. Rather, these observations document that the suppressive effects of opiates on gonadotropin secretion can be unmasked in the presence of an unopposed estrogen milieu.

The response of LH to exogenously administered estrogens was evaluated in a 63-year-old patient affected by complete testicular feminization syndrome (CTFS) with very low testosterone (T) levels, before and after gonadectomy. Prior to gonadectomy a durative fall in gonadotropin levels was observed after estrogen administration, without observing of an estrogenic positive feed-back (EPF) from LH. After gonadectomy, following an initial decrement in both gonadotropins, the characteristic. LH peak was seen, 48 h after E2B (Estradiol Benzoate) administration. This observation, together with the very low T levels that we found in this patient, prompted us to construe that absence of EPF in males is not due, as previously believed, to a direct inhibitory action of T or E2, deriving from T aromatization, on the hypothalamus, but by a still unknown gonadal factor. The hypothesis that this factor has a tubular origin is formulated and discussed.

Two siblings are presented, both with classic androgen-insensitivity syndrome (AIS). Endocrine testing was carried out and then gonadectomy was performed. Studies in these patients with AIS revealed low control serum FSH. In these patients serum FSH was not significantly suppressed by intravenous estrogen nor adequately stimulated by FSH-LH-releasing hormone but rose normally after castration. The various studies are interpreted in the light of the known kinetics of pituitary gonadotorpins and their modulation by gonadal steroids. A third sibling is also presented.

Gonadotropin control mechanisms were examined in 12 subjects with the complete syndrome of androgen insensitivity (testicular feminization). This study confirmed the presence of elevated luteinizing hormone (LH) and normal follicle-stimulating hormone (FSH) values in these subjects and suggests an intact feedback mechanism for FSH but not LH. This gives further credence to the opinion that estrogens and a nonsteroidal inhibin are important in FSH control. Because of an exaggerated pulsatile pattern of gonadotropins in intact and gonadectomized subjects, there were dramatic variations in gonadotropin levels. After gonadectomy, there was a marked rise in FSH and a further rise in LH. Administered estradiol benzoate and, to a lesser degree, testosterone propionate were capable of lowering LH levels. The effect of testosterone could be via conversion to estrogen(s) in the testes or elsewhere.